Merge branch 'release/0.13.0'

.travis.yml

@@ -14,7 +14,7 @@ cache:
 branches:
   only:
     - develop
-    - 0.12.0
+    - 0.13.0
 
 android:
  licenses:

app/build.gradle

@@ -17,8 +17,8 @@ android {
         testApplicationId "io.github.tests.wulkanowy"
         minSdkVersion 16
         targetSdkVersion 29
-        versionCode 47
+        versionCode 48
-        versionName "0.12.0"
+        versionName "0.13.0"
         multiDexEnabled true
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables.useSupportLibrary = true
@@ -110,8 +110,8 @@ play {
 }
 
 ext {
-    work_manager = "2.3.0-alpha03"
+    work_manager = "2.3.0-beta01"
-    room = "2.2.1"
+    room = "2.2.2"
     dagger = "2.25.2"
     chucker = "2.0.4"
     mockk = "1.9.2"
@@ -119,28 +119,27 @@ ext {
 
 configurations.all {
     resolutionStrategy.force "androidx.constraintlayout:constraintlayout:1.1.3"
-    resolutionStrategy.force "com.google.android.material:material:1.1.0-alpha07"
 }
 
 dependencies {
-    implementation "io.github.wulkanowy:api:0.12.0"
+    implementation "io.github.wulkanowy:api:0.13.0"
 
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation "androidx.core:core-ktx:1.2.0-beta01"
+    implementation "androidx.core:core-ktx:1.2.0-rc01"
-    implementation "androidx.activity:activity-ktx:1.1.0-rc01"
+    implementation "androidx.activity:activity-ktx:1.1.0-rc03"
     implementation "androidx.appcompat:appcompat:1.1.0"
     implementation "androidx.appcompat:appcompat-resources:1.1.0"
-    implementation "androidx.fragment:fragment-ktx:1.2.0-rc01"
+    implementation "androidx.fragment:fragment-ktx:1.2.0-rc03"
     implementation "androidx.annotation:annotation:1.1.0"
     implementation "androidx.multidex:multidex:2.0.1"
 
     implementation "androidx.preference:preference-ktx:1.1.0"
-    implementation "androidx.recyclerview:recyclerview:1.1.0-rc01"
+    implementation "androidx.recyclerview:recyclerview:1.1.0"
     implementation "androidx.viewpager:viewpager:1.0.0"
     implementation "androidx.swiperefreshlayout:swiperefreshlayout:1.1.0-alpha03"
     implementation "androidx.constraintlayout:constraintlayout:1.1.3"
-    implementation "androidx.coordinatorlayout:coordinatorlayout:1.1.0-rc01"
+    implementation "androidx.coordinatorlayout:coordinatorlayout:1.1.0"
-    implementation "com.google.android.material:material:1.1.0-alpha07"
+    implementation "com.google.android.material:material:1.1.0-beta02"
     implementation "com.github.wulkanowy:material-chips-input:2.0.1"
     implementation "com.github.PhilJay:MPAndroidChart:v3.1.0"
     implementation "me.zhanghai.android.materialprogressbar:library:1.6.1"
@@ -157,17 +156,18 @@ dependencies {
     implementation "com.google.dagger:dagger-android-support:$dagger"
     kapt "com.google.dagger:dagger-compiler:$dagger"
     kapt "com.google.dagger:dagger-android-processor:$dagger"
-    implementation "com.squareup.inject:assisted-inject-annotations-dagger2:0.5.0"
+    implementation "com.squareup.inject:assisted-inject-annotations-dagger2:0.5.2"
-    kapt "com.squareup.inject:assisted-inject-processor-dagger2:0.5.0"
+    kapt "com.squareup.inject:assisted-inject-processor-dagger2:0.5.2"
 
     implementation "eu.davidea:flexible-adapter:5.1.0"
     implementation "eu.davidea:flexible-adapter-ui:1.0.0"
     implementation "com.aurelhubert:ahbottomnavigation:2.3.4"
     implementation "com.ncapdevi:frag-nav:3.3.0"
+    implementation "com.github.YarikSOffice:lingver:1.1.0"
 
     implementation "com.github.pwittchen:reactivenetwork-rx2:3.0.6"
     implementation "io.reactivex.rxjava2:rxandroid:2.1.1"
-    implementation "io.reactivex.rxjava2:rxjava:2.2.13"
+    implementation "io.reactivex.rxjava2:rxjava:2.2.15"
 
     implementation "com.google.code.gson:gson:2.8.6"
     implementation "com.jakewharton.threetenabp:threetenabp:1.2.1"
@@ -175,6 +175,7 @@ dependencies {
     implementation "at.favre.lib:slf4j-timber:1.0.1"
     implementation "com.squareup.okhttp3:logging-interceptor:3.12.6"
     implementation "com.mikepenz:aboutlibraries:7.0.4"
+    implementation 'com.wdullaer:materialdatetimepicker:4.2.3'
 
     playImplementation "com.google.firebase:firebase-core:17.2.1"
     playImplementation "com.crashlytics.sdk.android:crashlytics:2.10.1"
@@ -187,7 +188,7 @@ dependencies {
     testImplementation "junit:junit:4.12"
     testImplementation "io.mockk:mockk:$mockk"
     testImplementation "org.threeten:threetenbp:1.4.0"
-    testImplementation "org.mockito:mockito-inline:3.1.0"
+    testImplementation "org.mockito:mockito-inline:3.2.0"
 
     androidTestImplementation "androidx.test:core:1.2.0"
     androidTestImplementation "androidx.test:runner:1.2.0"
@@ -195,7 +196,7 @@ dependencies {
     androidTestImplementation "io.mockk:mockk-android:$mockk"
     androidTestImplementation "androidx.room:room-testing:$room"
     androidTestImplementation "org.jetbrains.kotlin:kotlin-test:$kotlin_version"
-    androidTestImplementation "org.mockito:mockito-android:3.1.0"
+    androidTestImplementation "org.mockito:mockito-android:3.2.0"
 }
 
 apply plugin: 'com.google.gms.google-services'

app/src/debug/res/values-pl/strings.xml

@@ -1,3 +0,0 @@
-<resources>
-    <string name="app_name">Wulkanowy DEV</string>
-</resources>

app/src/main/java/io/github/wulkanowy/WulkanowyApp.kt

@@ -6,10 +6,13 @@ import android.util.Log.VERBOSE
 import androidx.multidex.MultiDex
 import androidx.work.Configuration
 import com.jakewharton.threetenabp.AndroidThreeTen
+import com.yariksoffice.lingver.Lingver
 import dagger.android.AndroidInjector
 import dagger.android.support.DaggerApplication
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.davidea.flexibleadapter.utils.Log
+import io.github.wulkanowy.data.db.SharedPrefProvider
+import io.github.wulkanowy.data.db.SharedPrefProvider.Companion.APP_VERSION_CODE_KEY
 import io.github.wulkanowy.di.DaggerAppComponent
 import io.github.wulkanowy.services.sync.SyncWorkerFactory
 import io.github.wulkanowy.ui.base.ThemeManager
@@ -32,6 +35,9 @@ class WulkanowyApp : DaggerApplication(), Configuration.Provider {
     @Inject
     lateinit var themeManager: ThemeManager
 
+    @Inject
+    lateinit var sharedPrefProvider: SharedPrefProvider
+
     @Inject
     lateinit var appInfo: AppInfo
 
@@ -44,7 +50,9 @@ class WulkanowyApp : DaggerApplication(), Configuration.Provider {
         super.onCreate()
         AndroidThreeTen.init(this)
         RxJavaPlugins.setErrorHandler(::onError)
+        Lingver.init(this)
         themeManager.applyDefaultTheme()
+        migrateSharedPreferences()
 
         initLogging()
         initCrashlytics(this, appInfo)
@@ -60,6 +68,13 @@ class WulkanowyApp : DaggerApplication(), Configuration.Provider {
         registerActivityLifecycleCallbacks(ActivityLifecycleLogger())
     }
 
+    private fun migrateSharedPreferences() {
+        if (sharedPrefProvider.getLong(APP_VERSION_CODE_KEY, -1) < 48) { // #596
+            sharedPrefProvider.delete(getString(R.string.pref_key_grade_modifier_plus))
+            sharedPrefProvider.delete(getString(R.string.pref_key_grade_modifier_minus))
+        }
+    }
+
     private fun onError(error: Throwable) {
         //RxJava's too deep stack traces may cause SOE on older android devices
         val cause = error.cause

app/src/main/java/io/github/wulkanowy/data/db/SharedPrefProvider.kt

@@ -8,6 +8,10 @@ import javax.inject.Singleton
 @Singleton
 class SharedPrefProvider @Inject constructor(private val sharedPref: SharedPreferences) {
 
+    companion object {
+        const val APP_VERSION_CODE_KEY = "app_version_code"
+    }
+
     fun putLong(key: String, value: Long, sync: Boolean = false) {
         sharedPref.edit(sync) { putLong(key, value) }
     }

app/src/main/java/io/github/wulkanowy/data/db/dao/AttendanceDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Attendance
 import io.reactivex.Maybe
@@ -11,13 +9,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface AttendanceDao {
+interface AttendanceDao : BaseDao<Attendance> {
-
-    @Insert
-    fun insertAll(exams: List<Attendance>): List<Long>
-
-    @Delete
-    fun deleteAll(exams: List<Attendance>)
 
     @Query("SELECT * FROM Attendance WHERE diary_id = :diaryId AND student_id = :studentId AND date >= :from AND date <= :end")
     fun loadAll(diaryId: Int, studentId: Int, from: LocalDate, end: LocalDate): Maybe<List<Attendance>>

app/src/main/java/io/github/wulkanowy/data/db/dao/AttendanceSummaryDao.kt

@@ -1,20 +1,12 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.AttendanceSummary
 import io.reactivex.Maybe
 
 @Dao
-interface AttendanceSummaryDao {
+interface AttendanceSummaryDao : BaseDao<AttendanceSummary> {
-
-    @Insert
-    fun insertAll(exams: List<AttendanceSummary>): List<Long>
-
-    @Delete
-    fun deleteAll(exams: List<AttendanceSummary>)
 
     @Query("SELECT * FROM AttendanceSummary WHERE diary_id = :diaryId AND student_id = :studentId AND subject_id = :subjectId")
     fun loadAll(diaryId: Int, studentId: Int, subjectId: Int): Maybe<List<AttendanceSummary>>

app/src/main/java/io/github/wulkanowy/data/db/dao/BaseDao.kt

@@ -0,0 +1,17 @@
+package io.github.wulkanowy.data.db.dao
+
+import androidx.room.Delete
+import androidx.room.Insert
+import androidx.room.Update
+
+interface BaseDao<T> {
+
+    @Insert
+    fun insertAll(items: List<T>): List<Long>
+
+    @Update
+    fun updateAll(items: List<T>)
+
+    @Delete
+    fun deleteAll(items: List<T>)
+}

app/src/main/java/io/github/wulkanowy/data/db/dao/CompletedLessonsDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.CompletedLesson
 import io.reactivex.Maybe
@@ -11,13 +9,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface CompletedLessonsDao {
+interface CompletedLessonsDao : BaseDao<CompletedLesson> {
-
-    @Insert
-    fun insertAll(exams: List<CompletedLesson>)
-
-    @Delete
-    fun deleteAll(exams: List<CompletedLesson>)
 
     @Query("SELECT * FROM CompletedLesson WHERE diary_id = :diaryId AND student_id = :studentId AND date >= :from AND date <= :end")
     fun loadAll(diaryId: Int, studentId: Int, from: LocalDate, end: LocalDate): Maybe<List<CompletedLesson>>

app/src/main/java/io/github/wulkanowy/data/db/dao/ExamDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Exam
 import io.reactivex.Maybe
@@ -11,13 +9,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface ExamDao {
+interface ExamDao : BaseDao<Exam> {
-
-    @Insert
-    fun insertAll(exams: List<Exam>): List<Long>
-
-    @Delete
-    fun deleteAll(exams: List<Exam>)
 
     @Query("SELECT * FROM Exams WHERE diary_id = :diaryId AND student_id = :studentId AND date >= :from AND date <= :end")
     fun loadAll(diaryId: Int, studentId: Int, from: LocalDate, end: LocalDate): Maybe<List<Exam>>

app/src/main/java/io/github/wulkanowy/data/db/dao/GradeDao.kt

@@ -1,26 +1,14 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
-import androidx.room.Update
 import io.github.wulkanowy.data.db.entities.Grade
 import io.reactivex.Maybe
 import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface GradeDao {
+interface GradeDao : BaseDao<Grade> {
-
-    @Insert
-    fun insertAll(grades: List<Grade>)
-
-    @Update
-    fun updateAll(grade: List<Grade>)
-
-    @Delete
-    fun deleteAll(grades: List<Grade>)
 
     @Query("SELECT * FROM Grades WHERE semester_id = :semesterId AND student_id = :studentId")
     fun loadAll(semesterId: Int, studentId: Int): Maybe<List<Grade>>

app/src/main/java/io/github/wulkanowy/data/db/dao/GradePointsStatisticsDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.GradePointsStatistics
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface GradePointsStatisticsDao {
+interface GradePointsStatisticsDao : BaseDao<GradePointsStatistics> {
-
-    @Insert
-    fun insertAll(gradesStatistics: List<GradePointsStatistics>)
-
-    @Delete
-    fun deleteAll(gradesStatistics: List<GradePointsStatistics>)
 
     @Query("SELECT * FROM GradesPointsStatistics WHERE student_id = :studentId AND semester_id = :semesterId AND subject = :subjectName")
     fun loadSubject(semesterId: Int, studentId: Int, subjectName: String): Maybe<GradePointsStatistics>

app/src/main/java/io/github/wulkanowy/data/db/dao/GradeStatisticsDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.GradeStatistics
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface GradeStatisticsDao {
+interface GradeStatisticsDao : BaseDao<GradeStatistics> {
-
-    @Insert
-    fun insertAll(gradesStatistics: List<GradeStatistics>)
-
-    @Delete
-    fun deleteAll(gradesStatistics: List<GradeStatistics>)
 
     @Query("SELECT * FROM GradesStatistics WHERE student_id = :studentId AND semester_id = :semesterId AND subject = :subjectName AND is_semester = :isSemester")
     fun loadSubject(semesterId: Int, studentId: Int, subjectName: String, isSemester: Boolean): Maybe<List<GradeStatistics>>

app/src/main/java/io/github/wulkanowy/data/db/dao/GradeSummaryDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.GradeSummary
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface GradeSummaryDao {
+interface GradeSummaryDao : BaseDao<GradeSummary> {
-
-    @Insert
-    fun insertAll(gradesSummary: List<GradeSummary>)
-
-    @Delete
-    fun deleteAll(gradesSummary: List<GradeSummary>)
 
     @Query("SELECT * FROM GradesSummary WHERE student_id = :studentId AND semester_id = :semesterId")
     fun loadAll(semesterId: Int, studentId: Int): Maybe<List<GradeSummary>>

app/src/main/java/io/github/wulkanowy/data/db/dao/HomeworkDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Homework
 import io.reactivex.Maybe
@@ -11,13 +9,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface HomeworkDao {
+interface HomeworkDao : BaseDao<Homework> {
-
-    @Insert
-    fun insertAll(homework: List<Homework>)
-
-    @Delete
-    fun deleteAll(homework: List<Homework>)
 
     @Query("SELECT * FROM Homework WHERE semester_id = :semesterId AND student_id = :studentId AND date >= :from AND date <= :end")
     fun loadAll(semesterId: Int, studentId: Int, from: LocalDate, end: LocalDate): Maybe<List<Homework>>

app/src/main/java/io/github/wulkanowy/data/db/dao/LuckyNumberDao.kt

@@ -1,10 +1,7 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
-import androidx.room.Update
 import io.github.wulkanowy.data.db.entities.LuckyNumber
 import io.reactivex.Maybe
 import org.threeten.bp.LocalDate
@@ -12,18 +9,8 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface LuckyNumberDao {
+interface LuckyNumberDao : BaseDao<LuckyNumber> {
-
-    @Insert
-    fun insert(luckyNumber: LuckyNumber)
-
-    @Update
-    fun update(luckyNumber: LuckyNumber)
-
-    @Delete
-    fun delete(luckyNumber: LuckyNumber)
 
     @Query("SELECT * FROM LuckyNumbers WHERE student_id = :studentId AND date = :date")
     fun load(studentId: Int, date: LocalDate): Maybe<LuckyNumber>
-
 }

app/src/main/java/io/github/wulkanowy/data/db/dao/MessagesDao.kt

@@ -1,24 +1,12 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
-import androidx.room.Update
 import io.github.wulkanowy.data.db.entities.Message
 import io.reactivex.Maybe
 
 @Dao
-interface MessagesDao {
+interface MessagesDao : BaseDao<Message> {
-
-    @Insert
-    fun insertAll(messages: List<Message>)
-
-    @Delete
-    fun deleteAll(messages: List<Message>)
-
-    @Update
-    fun updateAll(messages: List<Message>)
 
     @Query("SELECT * FROM Messages WHERE student_id = :studentId AND folder_id = :folder AND removed = 0 ORDER BY date DESC")
     fun loadAll(studentId: Int, folder: Int): Maybe<List<Message>>

app/src/main/java/io/github/wulkanowy/data/db/dao/MobileDeviceDao.kt

@@ -1,20 +1,12 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.MobileDevice
 import io.reactivex.Maybe
 
 @Dao
-interface MobileDeviceDao {
+interface MobileDeviceDao : BaseDao<MobileDevice> {
-
-    @Insert
-    fun insertAll(devices: List<MobileDevice>)
-
-    @Delete
-    fun deleteAll(devices: List<MobileDevice>)
 
     @Query("SELECT * FROM MobileDevices WHERE student_id = :studentId ORDER BY date DESC")
     fun loadAll(studentId: Int): Maybe<List<MobileDevice>>

app/src/main/java/io/github/wulkanowy/data/db/dao/NoteDao.kt

@@ -1,28 +1,15 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
-import androidx.room.Update
 import io.github.wulkanowy.data.db.entities.Note
 import io.reactivex.Maybe
 import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface NoteDao {
+interface NoteDao : BaseDao<Note> {
-
-    @Insert
-    fun insertAll(notes: List<Note>)
-
-    @Update
-    fun updateAll(notes: List<Note>)
-
-    @Delete
-    fun deleteAll(notes: List<Note>)
 
     @Query("SELECT * FROM Notes WHERE student_id = :studentId")
     fun loadAll(studentId: Int): Maybe<List<Note>>
-
 }

app/src/main/java/io/github/wulkanowy/data/db/dao/RecipientDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Recipient
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface RecipientDao {
+interface RecipientDao : BaseDao<Recipient> {
-
-    @Insert
-    fun insertAll(messages: List<Recipient>)
-
-    @Delete
-    fun deleteAll(messages: List<Recipient>)
 
     @Query("SELECT * FROM Recipients WHERE student_id = :studentId AND role = :role AND unit_id = :unitId")
     fun load(studentId: Int, role: Int, unitId: Int): Maybe<List<Recipient>>

app/src/main/java/io/github/wulkanowy/data/db/dao/ReportingUnitDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.ReportingUnit
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface ReportingUnitDao {
+interface ReportingUnitDao : BaseDao<ReportingUnit> {
-
-    @Insert
-    fun insertAll(reportingUnits: List<ReportingUnit>)
-
-    @Delete
-    fun deleteAll(reportingUnits: List<ReportingUnit>)
 
     @Query("SELECT * FROM ReportingUnits WHERE student_id = :studentId")
     fun load(studentId: Int): Maybe<List<ReportingUnit>>

app/src/main/java/io/github/wulkanowy/data/db/dao/SchoolDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.School
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface SchoolDao {
+interface SchoolDao : BaseDao<School> {
-
-    @Insert
-    fun insert(school: School)
-
-    @Delete
-    fun delete(school: School)
 
     @Query("SELECT * FROM School WHERE student_id = :studentId AND class_id = :classId")
     fun load(studentId: Int, classId: Int): Maybe<School>

app/src/main/java/io/github/wulkanowy/data/db/dao/SemesterDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Semester
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface SemesterDao {
+interface SemesterDao : BaseDao<Semester> {
-
-    @Insert
-    fun insertAll(semester: List<Semester>)
-
-    @Delete
-    fun deleteAll(semester: List<Semester>)
 
     @Query("SELECT * FROM Semesters WHERE student_id = :studentId AND class_id = :classId")
     fun loadAll(studentId: Int, classId: Int): Maybe<List<Semester>>

app/src/main/java/io/github/wulkanowy/data/db/dao/SubjectDao.kt

@@ -1,20 +1,12 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Subject
 import io.reactivex.Maybe
 
 @Dao
-interface SubjectDao {
+interface SubjectDao : BaseDao<Subject> {
-
-    @Insert
-    fun insertAll(subjects: List<Subject>): List<Long>
-
-    @Delete
-    fun deleteAll(subjects: List<Subject>)
 
     @Query("SELECT * FROM Subjects WHERE diary_id = :diaryId AND student_id = :studentId")
     fun loadAll(diaryId: Int, studentId: Int): Maybe<List<Subject>>

app/src/main/java/io/github/wulkanowy/data/db/dao/TeacherDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Teacher
 import io.reactivex.Maybe
@@ -10,13 +8,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface TeacherDao {
+interface TeacherDao : BaseDao<Teacher> {
-
-    @Insert
-    fun insertAll(teachers: List<Teacher>)
-
-    @Delete
-    fun deleteAll(teachers: List<Teacher>)
 
     @Query("SELECT * FROM Teachers WHERE student_id = :studentId AND class_id = :classId")
     fun loadAll(studentId: Int, classId: Int): Maybe<List<Teacher>>

app/src/main/java/io/github/wulkanowy/data/db/dao/TimetableDao.kt

@@ -1,8 +1,6 @@
 package io.github.wulkanowy.data.db.dao
 
 import androidx.room.Dao
-import androidx.room.Delete
-import androidx.room.Insert
 import androidx.room.Query
 import io.github.wulkanowy.data.db.entities.Timetable
 import io.reactivex.Maybe
@@ -11,13 +9,7 @@ import javax.inject.Singleton
 
 @Singleton
 @Dao
-interface TimetableDao {
+interface TimetableDao : BaseDao<Timetable> {
-
-    @Insert
-    fun insertAll(exams: List<Timetable>): List<Long>
-
-    @Delete
-    fun deleteAll(exams: List<Timetable>)
 
     @Query("SELECT * FROM Timetable WHERE diary_id = :diaryId AND student_id = :studentId AND date >= :from AND date <= :end")
     fun loadAll(diaryId: Int, studentId: Int, from: LocalDate, end: LocalDate): Maybe<List<Timetable>>

app/src/main/java/io/github/wulkanowy/data/repositories/luckynumber/LuckyNumberLocal.kt

@@ -12,15 +12,15 @@ import javax.inject.Singleton
 class LuckyNumberLocal @Inject constructor(private val luckyNumberDb: LuckyNumberDao) {
 
     fun saveLuckyNumber(luckyNumber: LuckyNumber) {
-        luckyNumberDb.insert(luckyNumber)
+        luckyNumberDb.insertAll(listOf(luckyNumber))
     }
 
     fun updateLuckyNumber(luckyNumber: LuckyNumber) {
-        luckyNumberDb.update(luckyNumber)
+        luckyNumberDb.updateAll(listOf(luckyNumber))
     }
 
     fun deleteLuckyNumber(luckyNumber: LuckyNumber) {
-        luckyNumberDb.delete(luckyNumber)
+        luckyNumberDb.deleteAll(listOf(luckyNumber))
     }
 
     fun getLuckyNumber(semester: Semester, date: LocalDate): Maybe<LuckyNumber> {

app/src/main/java/io/github/wulkanowy/data/repositories/message/MessageRemote.kt

@@ -11,7 +11,6 @@ import io.reactivex.Single
 import org.threeten.bp.LocalDateTime.now
 import javax.inject.Inject
 import javax.inject.Singleton
-import io.github.wulkanowy.api.messages.Message as ApiMessage
 import io.github.wulkanowy.api.messages.Recipient as ApiRecipient
 
 @Singleton

app/src/main/java/io/github/wulkanowy/data/repositories/mobiledevice/MobileDeviceLocal.kt

@@ -3,7 +3,6 @@ package io.github.wulkanowy.data.repositories.mobiledevice
 import io.github.wulkanowy.data.db.dao.MobileDeviceDao
 import io.github.wulkanowy.data.db.entities.MobileDevice
 import io.github.wulkanowy.data.db.entities.Semester
-import io.github.wulkanowy.data.db.entities.Student
 import io.reactivex.Maybe
 import javax.inject.Inject
 import javax.inject.Singleton

app/src/main/java/io/github/wulkanowy/data/repositories/preferences/PreferencesRepository.kt

@@ -33,6 +33,10 @@ class PreferencesRepository @Inject constructor(
     val gradeColorTheme: String
         get() = getString(R.string.pref_key_grade_color_scheme, R.string.pref_default_grade_color_scheme)
 
+    val appLanguageKey = context.getString(R.string.pref_key_app_language)
+    val appLanguage
+        get() = getString(appLanguageKey, R.string.pref_default_app_language)
+
     val serviceEnableKey = context.getString(R.string.pref_key_services_enable)
     val isServiceEnabled: Boolean
         get() = getBoolean(serviceEnableKey, R.bool.pref_default_services_enable)

app/src/main/java/io/github/wulkanowy/data/repositories/recipient/RecipientLocal.kt

@@ -15,7 +15,7 @@ class RecipientLocal @Inject constructor(private val recipientDb: RecipientDao)
         return recipientDb.load(student.studentId, role, unit.realId).filter { !it.isEmpty() }
     }
 
-    fun saveRecipients(recipients: List<Recipient>) {
+    fun saveRecipients(recipients: List<Recipient>): List<Long> {
         return recipientDb.insertAll(recipients)
     }
 

app/src/main/java/io/github/wulkanowy/data/repositories/reportingunit/ReportingUnitLocal.kt

@@ -18,7 +18,7 @@ class ReportingUnitLocal @Inject constructor(private val reportingUnitDb: Report
         return reportingUnitDb.loadOne(student.studentId, unitId)
     }
 
-    fun saveReportingUnits(reportingUnits: List<ReportingUnit>) {
+    fun saveReportingUnits(reportingUnits: List<ReportingUnit>): List<Long> {
         return reportingUnitDb.insertAll(reportingUnits)
     }
 

app/src/main/java/io/github/wulkanowy/data/repositories/school/SchoolLocal.kt

@@ -9,11 +9,11 @@ import javax.inject.Inject
 class SchoolLocal @Inject constructor(private val schoolDb: SchoolDao) {
 
     fun saveSchool(school: School) {
-        schoolDb.insert(school)
+        schoolDb.insertAll(listOf(school))
     }
 
     fun deleteSchool(school: School) {
-        schoolDb.delete(school)
+        schoolDb.deleteAll(listOf(school))
     }
 
     fun getSchool(semester: Semester): Maybe<School> {

app/src/main/java/io/github/wulkanowy/data/repositories/student/StudentLocal.kt

@@ -24,7 +24,7 @@ class StudentLocal @Inject constructor(
     fun getStudents(decryptPass: Boolean): Maybe<List<Student>> {
         return studentDb.loadAll()
             .map { list -> list.map { it.apply { if (decryptPass) password = decrypt(password) } } }
-            .filter { !it.isEmpty() }
+            .filter { it.isNotEmpty() }
     }
 
     fun getCurrentStudent(decryptPass: Boolean): Maybe<Student> {

app/src/main/java/io/github/wulkanowy/di/AppModule.kt

@@ -2,6 +2,7 @@ package io.github.wulkanowy.di
 
 import android.appwidget.AppWidgetManager
 import android.content.Context
+import com.yariksoffice.lingver.Lingver
 import dagger.Module
 import dagger.Provides
 import eu.davidea.flexibleadapter.FlexibleAdapter
@@ -32,4 +33,8 @@ internal class AppModule {
     @Singleton
     @Provides
     fun provideAppInfo() = AppInfo()
+
+    @Singleton
+    @Provides
+    fun provideLingver() = Lingver.getInstance()
 }

app/src/main/java/io/github/wulkanowy/services/sync/SyncManager.kt

@@ -11,6 +11,7 @@ import androidx.work.NetworkType.UNMETERED
 import androidx.work.PeriodicWorkRequestBuilder
 import androidx.work.WorkManager
 import io.github.wulkanowy.data.db.SharedPrefProvider
+import io.github.wulkanowy.data.db.SharedPrefProvider.Companion.APP_VERSION_CODE_KEY
 import io.github.wulkanowy.data.repositories.preferences.PreferencesRepository
 import io.github.wulkanowy.services.sync.channels.DebugChannel
 import io.github.wulkanowy.services.sync.channels.NewEntriesChannel
@@ -32,10 +33,6 @@ class SyncManager @Inject constructor(
     appInfo: AppInfo
 ) {
 
-    companion object {
-        private const val APP_VERSION_CODE_KEY = "app_version_code"
-    }
-
     init {
         if (now().isHolidays) stopSyncWorker()
 

app/src/main/java/io/github/wulkanowy/ui/base/BaseActivity.kt

@@ -22,7 +22,8 @@ import io.github.wulkanowy.utils.FragmentLifecycleLogger
 import io.github.wulkanowy.utils.getThemeAttrColor
 import javax.inject.Inject
 
-abstract class BaseActivity<T : BasePresenter<out BaseView>> : AppCompatActivity(), BaseView, HasAndroidInjector {
+abstract class BaseActivity<T : BasePresenter<out BaseView>> : AppCompatActivity(), BaseView,
+    HasAndroidInjector {
 
     @Inject
     lateinit var androidInjector: DispatchingAndroidInjector<Any>
@@ -53,13 +54,15 @@ abstract class BaseActivity<T : BasePresenter<out BaseView>> : AppCompatActivity
     override fun showError(text: String, error: Throwable) {
         if (messageContainer != null) {
             Snackbar.make(messageContainer!!, text, LENGTH_LONG)
-                .setAction(R.string.all_details) {
+                .setAction(R.string.all_details) { showErrorDetailsDialog(error) }
-                    ErrorDialog.newInstance(error).show(supportFragmentManager, error.toString())
-                }
                 .show()
         } else showMessage(text)
     }
 
+    override fun showErrorDetailsDialog(error: Throwable) {
+        ErrorDialog.newInstance(error).show(supportFragmentManager, error.toString())
+    }
+
     override fun showMessage(text: String) {
         if (messageContainer != null) Snackbar.make(messageContainer!!, text, LENGTH_LONG).show()
         else Toast.makeText(this, text, Toast.LENGTH_LONG).show()

app/src/main/java/io/github/wulkanowy/ui/base/BaseDialogFragment.kt

@@ -0,0 +1,27 @@
+package io.github.wulkanowy.ui.base
+
+import android.widget.Toast
+import dagger.android.support.DaggerAppCompatDialogFragment
+
+abstract class BaseDialogFragment : DaggerAppCompatDialogFragment(), BaseView {
+
+    override fun showError(text: String, error: Throwable) {
+        showMessage(text)
+    }
+
+    override fun showMessage(text: String) {
+        Toast.makeText(context, text, Toast.LENGTH_LONG).show()
+    }
+
+    override fun showExpiredDialog() {
+        (activity as? BaseActivity<*>)?.showExpiredDialog()
+    }
+
+    override fun openClearLoginView() {
+        (activity as? BaseActivity<*>)?.openClearLoginView()
+    }
+
+    override fun showErrorDetailsDialog(error: Throwable) {
+        ErrorDialog.newInstance(error).show(childFragmentManager, error.toString())
+    }
+}

app/src/main/java/io/github/wulkanowy/ui/base/BaseFragment.kt

@@ -13,15 +13,17 @@ abstract class BaseFragment : DaggerFragment(), BaseView {
     override fun showError(text: String, error: Throwable) {
         if (messageContainer != null) {
             Snackbar.make(messageContainer!!, text, LENGTH_LONG)
-                .setAction(R.string.all_details) {
+                .setAction(R.string.all_details) { if (isAdded) showErrorDetailsDialog(error) }
-                    if (isAdded) ErrorDialog.newInstance(error).show(childFragmentManager, error.toString())
-                }
                 .show()
         } else {
             (activity as? BaseActivity<*>)?.showError(text, error)
         }
     }
 
+    override fun showErrorDetailsDialog(error: Throwable) {
+        ErrorDialog.newInstance(error).show(childFragmentManager, error.toString())
+    }
+
     override fun showMessage(text: String) {
         if (messageContainer != null) {
             Snackbar.make(messageContainer!!, text, LENGTH_LONG).show()

app/src/main/java/io/github/wulkanowy/ui/base/BaseView.kt

@@ -9,4 +9,6 @@ interface BaseView {
     fun showExpiredDialog()
 
     fun openClearLoginView()
+
+    fun showErrorDetailsDialog(error: Throwable)
 }

app/src/main/java/io/github/wulkanowy/ui/modules/about/AboutFragment.kt

@@ -47,6 +47,11 @@ class AboutFragment : BaseFragment(), AboutView, MainView.TitledView {
             Triple(getString(R.string.about_feedback), getString(R.string.about_feedback_summary), getCompatDrawable(R.drawable.ic_about_feedback))
         }
 
+    override val faqRes: Triple<String, String, Drawable?>?
+        get() = context?.run {
+            Triple(getString(R.string.about_faq), getString(R.string.about_faq_summary), getCompatDrawable(R.drawable.ic_about_faq))
+        }
+
     override val discordRes: Triple<String, String, Drawable?>?
         get() = context?.run {
             Triple(getString(R.string.about_discord), getString(R.string.about_discord_summary), getCompatDrawable(R.drawable.ic_about_discord))
@@ -130,6 +135,10 @@ class AboutFragment : BaseFragment(), AboutView, MainView.TitledView {
         }
     }
 
+    override fun openFaqPage() {
+        context?.openInternetBrowser("https://wulkanowy.github.io/czesto-zadawane-pytania", ::showMessage)
+    }
+
     override fun openLicenses() {
         (activity as? MainActivity)?.pushView(LicenseFragment.newInstance())
     }

app/src/main/java/io/github/wulkanowy/ui/modules/about/AboutPresenter.kt

@@ -28,10 +28,15 @@ class AboutPresenter @Inject constructor(
         view?.run {
             when (item.title) {
                 feedbackRes?.first -> {
-                    Timber.i("Opening email client ")
+                    Timber.i("Opening email client")
                     openEmailClient()
                     analytics.logEvent("about_open", "name" to "feedback")
                 }
+                faqRes?.first -> {
+                    Timber.i("Opening faq page")
+                    openFaqPage()
+                    analytics.logEvent("about_open", "name" to "faq")
+                }
                 discordRes?.first -> {
                     Timber.i("Opening discord")
                     openDiscordInvite()
@@ -61,6 +66,7 @@ class AboutPresenter @Inject constructor(
             updateData(AboutScrollableHeader(), listOfNotNull(
                 versionRes?.let { (title, summary, image) -> AboutItem(title, summary, image) },
                 feedbackRes?.let { (title, summary, image) -> AboutItem(title, summary, image) },
+                faqRes?.let { (title, summary, image) -> AboutItem(title, summary, image) },
                 discordRes?.let { (title, summary, image) -> AboutItem(title, summary, image) },
                 homepageRes?.let { (title, summary, image) -> AboutItem(title, summary, image) },
                 licensesRes?.let { (title, summary, image) -> AboutItem(title, summary, image) },

app/src/main/java/io/github/wulkanowy/ui/modules/about/AboutView.kt

@@ -9,6 +9,8 @@ interface AboutView : BaseView {
 
     val feedbackRes: Triple<String, String, Drawable?>?
 
+    val faqRes: Triple<String, String, Drawable?>?
+
     val discordRes: Triple<String, String, Drawable?>?
 
     val homepageRes: Triple<String, String, Drawable?>?
@@ -25,6 +27,8 @@ interface AboutView : BaseView {
 
     fun openEmailClient()
 
+    fun openFaqPage()
+
     fun openHomepage()
 
     fun openLicenses()

app/src/main/java/io/github/wulkanowy/ui/modules/account/AccountDialog.kt

@@ -7,18 +7,17 @@ import android.view.ViewGroup
 import android.widget.Toast
 import android.widget.Toast.LENGTH_LONG
 import androidx.appcompat.app.AlertDialog
-import dagger.android.support.DaggerAppCompatDialogFragment
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.davidea.flexibleadapter.common.SmoothScrollLinearLayoutManager
 import eu.davidea.flexibleadapter.items.AbstractFlexibleItem
 import io.github.wulkanowy.R
-import io.github.wulkanowy.ui.base.BaseActivity
+import io.github.wulkanowy.ui.base.BaseDialogFragment
 import io.github.wulkanowy.ui.modules.login.LoginActivity
 import io.github.wulkanowy.utils.setOnItemClickListener
 import kotlinx.android.synthetic.main.dialog_account.*
 import javax.inject.Inject
 
-class AccountDialog : DaggerAppCompatDialogFragment(), AccountView {
+class AccountDialog : BaseDialogFragment(), AccountView {
 
     @Inject
     lateinit var presenter: AccountPresenter
@@ -77,14 +76,6 @@ class AccountDialog : DaggerAppCompatDialogFragment(), AccountView {
         }
     }
 
-    override fun showExpiredDialog() {
-        (activity as? BaseActivity<*>)?.showExpiredDialog()
-    }
-
-    override fun openClearLoginView() {
-        (activity as? BaseActivity<*>)?.openClearLoginView()
-    }
-
     override fun showConfirmDialog() {
         context?.let {
             AlertDialog.Builder(it)
@@ -105,4 +96,3 @@ class AccountDialog : DaggerAppCompatDialogFragment(), AccountView {
         super.onDestroy()
     }
 }
-

app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendanceFragment.kt

@@ -6,7 +6,11 @@ import android.view.Menu
 import android.view.MenuInflater
 import android.view.MenuItem
 import android.view.View
+import android.view.View.GONE
+import android.view.View.INVISIBLE
+import android.view.View.VISIBLE
 import android.view.ViewGroup
+import com.wdullaer.materialdatetimepicker.date.DatePickerDialog
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.davidea.flexibleadapter.common.FlexibleItemDecoration
 import eu.davidea.flexibleadapter.common.SmoothScrollLinearLayoutManager
@@ -17,9 +21,11 @@ import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.modules.attendance.summary.AttendanceSummaryFragment
 import io.github.wulkanowy.ui.modules.main.MainActivity
 import io.github.wulkanowy.ui.modules.main.MainView
+import io.github.wulkanowy.utils.SchooldaysRangeLimiter
 import io.github.wulkanowy.utils.dpToPx
 import io.github.wulkanowy.utils.setOnItemClickListener
 import kotlinx.android.synthetic.main.fragment_attendance.*
+import org.threeten.bp.LocalDate
 import javax.inject.Inject
 
 class AttendanceFragment : BaseFragment(), AttendanceView, MainView.MainChildView,
@@ -70,7 +76,11 @@ class AttendanceFragment : BaseFragment(), AttendanceView, MainView.MainChildVie
         }
 
         attendanceSwipe.setOnRefreshListener(presenter::onSwipeRefresh)
+        attendanceErrorRetry.setOnClickListener { presenter.onRetry() }
+        attendanceErrorDetails.setOnClickListener { presenter.onDetailsClick() }
+
         attendancePreviousButton.setOnClickListener { presenter.onPreviousDay() }
+        attendanceNavDate.setOnClickListener { presenter.onPickDate() }
         attendanceNextButton.setOnClickListener { presenter.onNextDay() }
 
         attendanceNavContainer.setElevationCompat(requireContext().dpToPx(8f))
@@ -110,11 +120,19 @@ class AttendanceFragment : BaseFragment(), AttendanceView, MainView.MainChildVie
     }
 
     override fun showEmpty(show: Boolean) {
-        attendanceEmpty.visibility = if (show) View.VISIBLE else View.GONE
+        attendanceEmpty.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun showErrorView(show: Boolean) {
+        attendanceError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        attendanceErrorMessage.text = message
     }
 
     override fun showProgress(show: Boolean) {
-        attendanceProgress.visibility = if (show) View.VISIBLE else View.GONE
+        attendanceProgress.visibility = if (show) VISIBLE else GONE
     }
 
     override fun enableSwipe(enable: Boolean) {
@@ -122,7 +140,7 @@ class AttendanceFragment : BaseFragment(), AttendanceView, MainView.MainChildVie
     }
 
     override fun showContent(show: Boolean) {
-        attendanceRecycler.visibility = if (show) View.VISIBLE else View.GONE
+        attendanceRecycler.visibility = if (show) VISIBLE else GONE
     }
 
     override fun hideRefresh() {
@@ -130,17 +148,32 @@ class AttendanceFragment : BaseFragment(), AttendanceView, MainView.MainChildVie
     }
 
     override fun showPreButton(show: Boolean) {
-        attendancePreviousButton.visibility = if (show) View.VISIBLE else View.INVISIBLE
+        attendancePreviousButton.visibility = if (show) VISIBLE else INVISIBLE
     }
 
     override fun showNextButton(show: Boolean) {
-        attendanceNextButton.visibility = if (show) View.VISIBLE else View.INVISIBLE
+        attendanceNextButton.visibility = if (show) VISIBLE else INVISIBLE
     }
 
     override fun showAttendanceDialog(lesson: Attendance) {
         (activity as? MainActivity)?.showDialogFragment(AttendanceDialog.newInstance(lesson))
     }
 
+    override fun showDatePickerDialog(currentDate: LocalDate) {
+        val dateSetListener = DatePickerDialog.OnDateSetListener { _, year, month, dayOfMonth ->
+            presenter.onDateSet(year, month + 1, dayOfMonth)
+        }
+        val datePickerDialog = DatePickerDialog.newInstance(dateSetListener,
+            currentDate.year, currentDate.monthValue - 1, currentDate.dayOfMonth)
+
+        with(datePickerDialog) {
+            setDateRangeLimiter(SchooldaysRangeLimiter())
+            version = DatePickerDialog.Version.VERSION_2
+            scrollOrientation = DatePickerDialog.ScrollOrientation.VERTICAL
+            show(this@AttendanceFragment.parentFragmentManager, null)
+        }
+    }
+
     override fun openSummaryView() {
         (activity as? MainActivity)?.pushView(AttendanceSummaryFragment.newInstance())
     }

app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendancePresenter.kt

@@ -1,5 +1,6 @@
 package io.github.wulkanowy.ui.modules.attendance
 
+import android.annotation.SuppressLint
 import eu.davidea.flexibleadapter.items.AbstractFlexibleItem
 import io.github.wulkanowy.data.repositories.attendance.AttendanceRepository
 import io.github.wulkanowy.data.repositories.preferences.PreferencesRepository
@@ -37,10 +38,13 @@ class AttendancePresenter @Inject constructor(
     lateinit var currentDate: LocalDate
         private set
 
+    private lateinit var lastError: Throwable
+
     fun onAttachView(view: AttendanceView, date: Long?) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Attendance view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData(ofEpochDay(date ?: baseDate.toEpochDay()))
         if (currentDate.isHolidays) setBaseDateOnHolidays()
         reloadView()
@@ -56,11 +60,32 @@ class AttendancePresenter @Inject constructor(
         reloadView()
     }
 
+    fun onPickDate() {
+        view?.showDatePickerDialog(currentDate)
+    }
+
+    fun onDateSet(year: Int, month: Int, day: Int) {
+        loadData(LocalDate.of(year, month, day))
+        reloadView()
+    }
+
     fun onSwipeRefresh() {
         Timber.i("Force refreshing the attendance")
         loadData(currentDate, true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(currentDate, true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onViewReselected() {
         Timber.i("Attendance view is reselected")
         view?.also { view ->
@@ -130,18 +155,29 @@ class AttendancePresenter @Inject constructor(
                     view?.apply {
                         updateData(it)
                         showEmpty(it.isEmpty())
+                        showErrorView(false)
                         showContent(it.isNotEmpty())
                     }
                     analytics.logEvent("load_attendance", "items" to it.size, "force_refresh" to forceRefresh)
                 }) {
                     Timber.i("Loading attendance result: An exception occurred")
-                    view?.run { showEmpty(isViewEmpty) }
                     errorHandler.dispatch(it)
                 }
             )
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     private fun reloadView() {
         Timber.i("Reload attendance view with the date ${currentDate.toFormattedString()}")
         view?.apply {
@@ -149,11 +185,13 @@ class AttendancePresenter @Inject constructor(
             enableSwipe(false)
             showContent(false)
             showEmpty(false)
+            showErrorView(false)
             clearData()
             reloadNavigation()
         }
     }
 
+    @SuppressLint("DefaultLocale")
     private fun reloadNavigation() {
         view?.apply {
             showPreButton(!currentDate.minusDays(1).isHolidays)

app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendanceView.kt

@@ -2,6 +2,7 @@ package io.github.wulkanowy.ui.modules.attendance
 
 import io.github.wulkanowy.data.db.entities.Attendance
 import io.github.wulkanowy.ui.base.BaseView
+import org.threeten.bp.LocalDate
 
 interface AttendanceView : BaseView {
 
@@ -23,6 +24,10 @@ interface AttendanceView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)
@@ -35,6 +40,8 @@ interface AttendanceView : BaseView {
 
     fun showAttendanceDialog(lesson: Attendance)
 
+    fun showDatePickerDialog(currentDate: LocalDate)
+
     fun openSummaryView()
 
     fun popView()

app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryFragment.kt

@@ -57,6 +57,8 @@ class AttendanceSummaryFragment : BaseFragment(), AttendanceSummaryView, MainVie
         }
 
         attendanceSummarySwipe.setOnRefreshListener(presenter::onSwipeRefresh)
+        attendanceSummaryErrorRetry.setOnClickListener { presenter.onRetry() }
+        attendanceSummaryErrorDetails.setOnClickListener { presenter.onDetailsClick() }
 
         subjectsAdapter = ArrayAdapter(requireContext(), android.R.layout.simple_spinner_item, mutableListOf())
         subjectsAdapter.setDropDownViewResource(R.layout.item_attendance_summary_subject)
@@ -93,6 +95,14 @@ class AttendanceSummaryFragment : BaseFragment(), AttendanceSummaryView, MainVie
         attendanceSummaryEmpty.visibility = if (show) VISIBLE else GONE
     }
 
+    override fun showErrorView(show: Boolean) {
+        attendanceSummaryError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        attendanceSummaryErrorMessage.text = message
+    }
+
     override fun showProgress(show: Boolean) {
         attendanceSummaryProgress.visibility = if (show) VISIBLE else GONE
     }

app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryPresenter.kt

@@ -33,10 +33,13 @@ class AttendanceSummaryPresenter @Inject constructor(
     var currentSubjectId = -1
         private set
 
+    private lateinit var lastError: Throwable
+
     fun onAttachView(view: AttendanceSummaryView, subjectId: Int?) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Attendance summary view was initialized with subject id ${subjectId ?: -1}")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData(subjectId ?: -1)
         loadSubjects()
     }
@@ -46,12 +49,26 @@ class AttendanceSummaryPresenter @Inject constructor(
         loadData(currentSubjectId, true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(currentSubjectId, true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onSubjectSelected(name: String?) {
         Timber.i("Select attendance summary subject $name")
         view?.run {
             showContent(false)
             showProgress(true)
             enableSwipe(false)
+            showEmpty(false)
+            showErrorView(false)
             clearView()
         }
         (subjects.singleOrNull { it.name == name }?.realId ?: -1).let {
@@ -88,13 +105,23 @@ class AttendanceSummaryPresenter @Inject constructor(
                     analytics.logEvent("load_attendance_summary", "items" to it.first.size, "force_refresh" to forceRefresh, "item_id" to subjectId)
                 }) {
                     Timber.i("Loading attendance summary result: An exception occurred")
-                    view?.run { showEmpty(isViewEmpty) }
                     errorHandler.dispatch(it)
                 }
             )
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     private fun loadSubjects() {
         Timber.i("Loading attendance summary subjects started")
         disposable.add(studentRepository.getCurrentStudent()

app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryView.kt

@@ -18,6 +18,10 @@ interface AttendanceSummaryView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun updateDataSet(data: List<AttendanceSummaryItem>, header: AttendanceSummaryScrollableHeader)
 
     fun updateSubjects(data: ArrayList<String>)

app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamFragment.kt

@@ -61,6 +61,9 @@ class ExamFragment : BaseFragment(), ExamView, MainView.MainChildView, MainView.
         }
 
         examSwipe.setOnRefreshListener(presenter::onSwipeRefresh)
+        examErrorRetry.setOnClickListener { presenter.onRetry() }
+        examErrorDetails.setOnClickListener { presenter.onDetailsClick() }
+
         examPreviousButton.setOnClickListener { presenter.onPreviousWeek() }
         examNextButton.setOnClickListener { presenter.onNextWeek() }
 
@@ -95,6 +98,14 @@ class ExamFragment : BaseFragment(), ExamView, MainView.MainChildView, MainView.
         examEmpty.visibility = if (show) VISIBLE else GONE
     }
 
+    override fun showErrorView(show: Boolean) {
+        examError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        examErrorMessage.text = message
+    }
+
     override fun showProgress(show: Boolean) {
         examProgress.visibility = if (show) VISIBLE else GONE
     }

app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamPresenter.kt

@@ -36,10 +36,13 @@ class ExamPresenter @Inject constructor(
     lateinit var currentDate: LocalDate
         private set
 
+    private lateinit var lastError: Throwable
+
     fun onAttachView(view: ExamView, date: Long?) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Exam view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData(ofEpochDay(date ?: baseDate.toEpochDay()))
         if (currentDate.isHolidays) setBaseDateOnHolidays()
         reloadView()
@@ -60,6 +63,18 @@ class ExamPresenter @Inject constructor(
         loadData(currentDate, true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(currentDate, true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onExamItemSelected(item: AbstractFlexibleItem<*>?) {
         if (item is ExamItem) {
             Timber.i("Select exam item ${item.exam.id}")
@@ -116,17 +131,28 @@ class ExamPresenter @Inject constructor(
                     view?.apply {
                         updateData(it)
                         showEmpty(it.isEmpty())
+                        showErrorView(false)
                         showContent(it.isNotEmpty())
                     }
                     analytics.logEvent("load_exam", "items" to it.size, "force_refresh" to forceRefresh)
                 }) {
                     Timber.i("Loading exam result: An exception occurred")
-                    view?.run { showEmpty(isViewEmpty) }
                     errorHandler.dispatch(it)
                 })
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     private fun createExamItems(items: Map<LocalDate, List<Exam>>): List<ExamItem> {
         return items.flatMap {
             ExamHeader(it.key).let { header ->
@@ -142,6 +168,7 @@ class ExamPresenter @Inject constructor(
             enableSwipe(false)
             showContent(false)
             showEmpty(false)
+            showErrorView(false)
             clearData()
             reloadNavigation()
         }

app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamView.kt

@@ -21,6 +21,10 @@ interface ExamView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/grade/GradeFragment.kt

@@ -13,6 +13,7 @@ import androidx.appcompat.app.AlertDialog
 import io.github.wulkanowy.R
 import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.base.BaseFragmentPagerAdapter
+import io.github.wulkanowy.ui.base.ErrorDialog
 import io.github.wulkanowy.ui.modules.grade.details.GradeDetailsFragment
 import io.github.wulkanowy.ui.modules.grade.statistics.GradeStatisticsFragment
 import io.github.wulkanowy.ui.modules.grade.summary.GradeSummaryFragment
@@ -83,7 +84,8 @@ class GradeFragment : BaseFragment(), GradeView, MainView.MainChildView, MainVie
             setElevationCompat(context.dpToPx(4f))
         }
 
-        gradeSwipe.setOnRefreshListener(presenter::onSwipeRefresh)
+        gradeErrorRetry.setOnClickListener { presenter.onRetry() }
+        gradeErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
@@ -104,22 +106,18 @@ class GradeFragment : BaseFragment(), GradeView, MainView.MainChildView, MainVie
         gradeProgress.visibility = if (show) VISIBLE else INVISIBLE
     }
 
-    override fun showEmpty(show: Boolean) {
+    override fun showErrorView(show: Boolean) {
-        gradeEmpty.visibility = if (show) VISIBLE else INVISIBLE
+        gradeError.visibility = if (show) VISIBLE else INVISIBLE
     }
 
-    override fun showRefresh(show: Boolean) {
+    override fun setErrorDetails(message: String) {
-        gradeSwipe.isRefreshing = show
+        gradeErrorMessage.text = message
     }
 
     override fun showSemesterSwitch(show: Boolean) {
         semesterSwitchMenu?.isVisible = show
     }
 
-    override fun enableSwipe(enable: Boolean) {
-        gradeSwipe.isEnabled = enable
-    }
-
     override fun showSemesterDialog(selectedIndex: Int) {
         val choices = arrayOf(
             getString(R.string.grade_semester, 1),

app/src/main/java/io/github/wulkanowy/ui/modules/grade/GradePresenter.kt

@@ -25,14 +25,14 @@ class GradePresenter @Inject constructor(
 
     private val loadedSemesterId = mutableMapOf<Int, Int>()
 
+    private lateinit var lastError: Throwable
+
     fun onAttachView(view: GradeView, savedIndex: Int?) {
         super.onAttachView(view)
         selectedIndex = savedIndex ?: 0
-        view.run {
+        view.initView()
-            initView()
-            enableSwipe(false)
-        }
         Timber.i("Grade view was initialized with $selectedIndex index")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData()
     }
 
@@ -71,7 +71,7 @@ class GradePresenter @Inject constructor(
         view?.apply {
             showContent(true)
             showProgress(false)
-            showEmpty(false)
+            showErrorView(false)
             loadedSemesterId[currentPageIndex] = semesterId
         }
     }
@@ -80,10 +80,18 @@ class GradePresenter @Inject constructor(
         if (semesters.isNotEmpty()) loadChild(index)
     }
 
-    fun onSwipeRefresh() {
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
         loadData()
     }
 
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     private fun loadData() {
         Timber.i("Loading grade data started")
         disposable.add(studentRepository.getCurrentStudent()
@@ -96,25 +104,28 @@ class GradePresenter @Inject constructor(
             }
             .subscribeOn(schedulers.backgroundThread)
             .observeOn(schedulers.mainThread)
-            .doFinally { view?.showRefresh(false) }
+            .doFinally { view?.showProgress(false) }
             .subscribe({
                 view?.run {
                     Timber.i("Loading grade result: Attempt load index $currentPageIndex")
                     loadChild(currentPageIndex)
-                    enableSwipe(false)
+                    showErrorView(false)
                     showSemesterSwitch(true)
                 }
             }) {
                 Timber.i("Loading grade result: An exception occurred")
                 errorHandler.dispatch(it)
-                view?.run {
-                    showProgress(false)
-                    showEmpty(true)
-                    enableSwipe(true)
-                }
             })
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        lastError = error
+        view?.run {
+            showErrorView(true)
+            setErrorDetails(message)
+        }
+    }
+
     private fun loadChild(index: Int, forceRefresh: Boolean = false) {
         semesters.first { it.semesterName == selectedIndex }.semesterId.also {
             if (forceRefresh || loadedSemesterId[index] != it) {

app/src/main/java/io/github/wulkanowy/ui/modules/grade/GradeView.kt

@@ -12,16 +12,14 @@ interface GradeView : BaseView {
 
     fun showProgress(show: Boolean)
 
-    fun showEmpty(show: Boolean)
+    fun showErrorView(show: Boolean)
 
-    fun showRefresh(show: Boolean)
+    fun setErrorDetails(message: String)
 
     fun showSemesterSwitch(show: Boolean)
 
     fun showSemesterDialog(selectedIndex: Int)
 
-    fun enableSwipe(enable: Boolean)
-
     fun notifyChildLoadData(index: Int, semesterId: Int, forceRefresh: Boolean)
 
     fun notifyChildParentReselected(index: Int)

app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsFragment.kt

@@ -18,6 +18,7 @@ import eu.davidea.flexibleadapter.items.IFlexible
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.db.entities.Grade
 import io.github.wulkanowy.ui.base.BaseFragment
+import io.github.wulkanowy.ui.base.ErrorDialog
 import io.github.wulkanowy.ui.modules.grade.GradeFragment
 import io.github.wulkanowy.ui.modules.grade.GradeView
 import io.github.wulkanowy.ui.modules.main.MainActivity
@@ -90,6 +91,8 @@ class GradeDetailsFragment : BaseFragment(), GradeDetailsView, GradeView.GradeCh
             )
         }
         gradeDetailsSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        gradeDetailsErrorRetry.setOnClickListener { presenter.onRetry() }
+        gradeDetailsErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
@@ -141,6 +144,14 @@ class GradeDetailsFragment : BaseFragment(), GradeDetailsView, GradeView.GradeCh
         gradeDetailsEmpty.visibility = if (show) VISIBLE else INVISIBLE
     }
 
+    override fun showErrorView(show: Boolean) {
+        gradeDetailsError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        gradeDetailsErrorMessage.text = message
+    }
+
     override fun showRefresh(show: Boolean) {
         gradeDetailsSwipe.isRefreshing = show
     }

app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsPresenter.kt

@@ -1,6 +1,5 @@
 package io.github.wulkanowy.ui.modules.grade.details
 
-import android.widget.Toast
 import eu.davidea.flexibleadapter.items.AbstractFlexibleItem
 import io.github.wulkanowy.data.db.entities.Grade
 import io.github.wulkanowy.data.repositories.grade.GradeRepository
@@ -31,9 +30,12 @@ class GradeDetailsPresenter @Inject constructor(
 
     private var currentSemesterId = 0
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: GradeDetailsView) {
         super.onAttachView(view)
         view.initView()
+        errorHandler.showErrorMessage = ::showErrorViewOnError
     }
 
     fun onParentViewLoadData(semesterId: Int, forceRefresh: Boolean) {
@@ -90,6 +92,18 @@ class GradeDetailsPresenter @Inject constructor(
         view?.notifyParentRefresh()
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        view?.notifyParentRefresh()
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onParentViewReselected() {
         view?.run {
             if (!isViewEmpty) {
@@ -144,17 +158,28 @@ class GradeDetailsPresenter @Inject constructor(
                 updateMarkAsDoneButton()
                 view?.run {
                     showEmpty(it.isEmpty())
+                    showErrorView(false)
                     showContent(it.isNotEmpty())
                     updateData(it)
                 }
                 analytics.logEvent("load_grade_details", "items" to it.size, "force_refresh" to forceRefresh)
             }) {
                 Timber.i("Loading grade details result: An exception occurred")
-                view?.run { showEmpty(isViewEmpty) }
                 errorHandler.dispatch(it)
             })
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     private fun createGradeItems(items: Map<String, List<Grade>>, averages: Map<String, Double>): List<GradeDetailsHeader> {
         val isGradeExpandable = preferencesRepository.isGradeExpandable
         val gradeColorTheme = preferencesRepository.gradeColorTheme

app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsView.kt

@@ -38,6 +38,10 @@ interface GradeDetailsView : BaseView {
 
     fun showProgress(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun enableSwipe(enable: Boolean)
 
     fun showRefresh(show: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/grade/statistics/GradeStatisticsFragment.kt

@@ -111,9 +111,11 @@ class GradeStatisticsFragment : BaseFragment(), GradeStatisticsView, GradeView.G
             setOnItemSelectedListener<TextView> { presenter.onSubjectSelected(it?.text?.toString()) }
         }
 
-        gradeStatisticsSwipe.setOnRefreshListener(presenter::onSwipeRefresh)
-
         gradeStatisticsSubjectsContainer.setElevationCompat(requireContext().dpToPx(1f))
+
+        gradeStatisticsSwipe.setOnRefreshListener(presenter::onSwipeRefresh)
+        gradeStatisticsErrorRetry.setOnClickListener { presenter.onRetry() }
+        gradeStatisticsErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun updateSubjects(data: ArrayList<String>) {
@@ -228,6 +230,14 @@ class GradeStatisticsFragment : BaseFragment(), GradeStatisticsView, GradeView.G
         gradeStatisticsEmpty.visibility = if (show) View.VISIBLE else View.INVISIBLE
     }
 
+    override fun showErrorView(show: Boolean) {
+        gradeStatisticsError.visibility = if (show) View.VISIBLE else View.GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        gradeStatisticsErrorMessage.text = message
+    }
+
     override fun showProgress(show: Boolean) {
         gradeStatisticsProgress.visibility = if (show) View.VISIBLE else View.GONE
     }

app/src/main/java/io/github/wulkanowy/ui/modules/grade/statistics/GradeStatisticsPresenter.kt

@@ -30,6 +30,8 @@ class GradeStatisticsPresenter @Inject constructor(
 
     private var currentSubjectName: String = "Wszystkie"
 
+    private lateinit var lastError: Throwable
+
     var currentType: ViewType = ViewType.PARTIAL
         private set
 
@@ -37,6 +39,7 @@ class GradeStatisticsPresenter @Inject constructor(
         super.onAttachView(view)
         currentType = type ?: ViewType.PARTIAL
         view.initView()
+        errorHandler.showErrorMessage = ::showErrorViewOnError
     }
 
     fun onParentViewLoadData(semesterId: Int, forceRefresh: Boolean) {
@@ -51,6 +54,7 @@ class GradeStatisticsPresenter @Inject constructor(
             enableSwipe(false)
             showRefresh(false)
             showBarContent(false)
+            showErrorView(false)
             showEmpty(false)
             clearView()
         }
@@ -62,6 +66,18 @@ class GradeStatisticsPresenter @Inject constructor(
         view?.notifyParentRefresh()
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        view?.notifyParentRefresh()
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onSubjectSelected(name: String?) {
         Timber.i("Select grade stats subject $name")
         view?.run {
@@ -70,6 +86,7 @@ class GradeStatisticsPresenter @Inject constructor(
             showProgress(true)
             enableSwipe(false)
             showEmpty(false)
+            showErrorView(false)
             clearView()
         }
         (subjects.singleOrNull { it.name == name }?.name)?.let {
@@ -86,6 +103,7 @@ class GradeStatisticsPresenter @Inject constructor(
             showProgress(true)
             enableSwipe(false)
             showEmpty(false)
+            showErrorView(false)
             clearView()
         }
         loadDataByType(currentSemesterId, currentSubjectName, type)
@@ -146,12 +164,12 @@ class GradeStatisticsPresenter @Inject constructor(
                     showEmpty(it.isEmpty())
                     showBarContent(false)
                     showPieContent(it.isNotEmpty())
+                    showErrorView(false)
                     updatePieData(it, preferencesRepository.gradeColorTheme)
                 }
                 analytics.logEvent("load_grade_statistics", "items" to it.size, "force_refresh" to forceRefresh)
             }) {
                 Timber.e("Loading grade stats result: An exception occurred")
-                view?.run { showEmpty(isPieViewEmpty) }
                 errorHandler.dispatch(it)
             })
     }
@@ -177,12 +195,12 @@ class GradeStatisticsPresenter @Inject constructor(
                     showEmpty(false)
                     showPieContent(false)
                     showBarContent(true)
+                    showErrorView(false)
                     updateBarData(it)
                 }
                 analytics.logEvent("load_grade_points_statistics", "force_refresh" to forceRefresh)
             }, {
                 Timber.e("Loading grade points stats result: An exception occurred")
-                view?.run { showEmpty(isBarViewEmpty) }
                 errorHandler.dispatch(it)
             }, {
                 Timber.d("Loading grade points stats result: No point stats found")
@@ -193,4 +211,15 @@ class GradeStatisticsPresenter @Inject constructor(
             })
         )
     }
+
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isBarViewEmpty || isPieViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/grade/statistics/GradeStatisticsView.kt

@@ -32,6 +32,10 @@ interface GradeStatisticsView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/grade/summary/GradeSummaryFragment.kt

@@ -56,6 +56,8 @@ class GradeSummaryFragment : BaseFragment(), GradeSummaryView, GradeView.GradeCh
             adapter = gradeSummaryAdapter
         }
         gradeSummarySwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        gradeSummaryErrorRetry.setOnClickListener { presenter.onRetry() }
+        gradeSummaryErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun updateData(data: List<GradeSummaryItem>, header: GradeSummaryScrollableHeader) {
@@ -82,6 +84,14 @@ class GradeSummaryFragment : BaseFragment(), GradeSummaryView, GradeView.GradeCh
         gradeSummaryEmpty.visibility = if (show) VISIBLE else INVISIBLE
     }
 
+    override fun showErrorView(show: Boolean) {
+        gradeSummaryError.visibility = if (show) VISIBLE else INVISIBLE
+    }
+
+    override fun setErrorDetails(message: String) {
+        gradeSummaryErrorMessage.text = message
+    }
+
     override fun showProgress(show: Boolean) {
         gradeSummaryProgress.visibility = if (show) VISIBLE else GONE
     }

app/src/main/java/io/github/wulkanowy/ui/modules/grade/summary/GradeSummaryPresenter.kt

@@ -25,9 +25,12 @@ class GradeSummaryPresenter @Inject constructor(
     private val analytics: FirebaseAnalyticsHelper
 ) : BasePresenter<GradeSummaryView>(errorHandler, studentRepository, schedulers) {
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: GradeSummaryView) {
         super.onAttachView(view)
         view.initView()
+        errorHandler.showErrorMessage = ::showErrorViewOnError
     }
 
     fun onParentViewLoadData(semesterId: Int, forceRefresh: Boolean) {
@@ -56,21 +59,44 @@ class GradeSummaryPresenter @Inject constructor(
                 view?.run {
                     showEmpty(gradeSummaryItems.isEmpty())
                     showContent(gradeSummaryItems.isNotEmpty())
+                    showErrorView(false)
                     updateData(gradeSummaryItems, gradeSummaryHeader)
                 }
                 analytics.logEvent("load_grade_summary", "items" to gradeSummaryItems.size, "force_refresh" to forceRefresh)
             }) {
                 Timber.i("Loading grade summary result: An exception occurred")
-                view?.run { showEmpty(isViewEmpty) }
                 errorHandler.dispatch(it)
             })
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     fun onSwipeRefresh() {
         Timber.i("Force refreshing the grade summary")
         view?.notifyParentRefresh()
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        view?.notifyParentRefresh()
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onParentViewReselected() {
         view?.run {
             if (!isViewEmpty) resetView()

app/src/main/java/io/github/wulkanowy/ui/modules/grade/summary/GradeSummaryView.kt

@@ -26,6 +26,10 @@ interface GradeSummaryView : BaseView {
 
     fun showContent(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showEmpty(show: Boolean)
 
     fun notifyParentDataLoaded(semesterId: Int)

app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkFragment.kt

@@ -3,6 +3,8 @@ package io.github.wulkanowy.ui.modules.homework
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
+import android.view.View.GONE
+import android.view.View.VISIBLE
 import android.view.ViewGroup
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.davidea.flexibleadapter.common.FlexibleItemDecoration
@@ -34,6 +36,8 @@ class HomeworkFragment : BaseFragment(), HomeworkView, MainView.TitledView {
 
     override val titleStringId get() = R.string.homework_title
 
+    override val isViewEmpty get() = homeworkAdapter.isEmpty
+
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         return inflater.inflate(R.layout.fragment_homework, container, false)
     }
@@ -41,7 +45,7 @@ class HomeworkFragment : BaseFragment(), HomeworkView, MainView.TitledView {
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
         messageContainer = homeworkRecycler
-        presenter.onAttachView(this, savedInstanceState?.getLong(HomeworkFragment.SAVED_DATE_KEY))
+        presenter.onAttachView(this, savedInstanceState?.getLong(SAVED_DATE_KEY))
     }
 
     override fun initView() {
@@ -56,6 +60,9 @@ class HomeworkFragment : BaseFragment(), HomeworkView, MainView.TitledView {
         }
 
         homeworkSwipe.setOnRefreshListener(presenter::onSwipeRefresh)
+        homeworkErrorRetry.setOnClickListener { presenter.onRetry() }
+        homeworkErrorDetails.setOnClickListener { presenter.onDetailsClick() }
+
         homeworkPreviousButton.setOnClickListener { presenter.onPreviousDay() }
         homeworkNextButton.setOnClickListener { presenter.onNextDay() }
 
@@ -74,18 +81,24 @@ class HomeworkFragment : BaseFragment(), HomeworkView, MainView.TitledView {
         homeworkNavDate.text = date
     }
 
-    override fun isViewEmpty() = homeworkAdapter.isEmpty
-
     override fun hideRefresh() {
         homeworkSwipe.isRefreshing = false
     }
 
     override fun showEmpty(show: Boolean) {
-        homeworkEmpty.visibility = if (show) View.VISIBLE else View.GONE
+        homeworkEmpty.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun showErrorView(show: Boolean) {
+        homeworkError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        homeworkErrorMessage.text = message
     }
 
     override fun showProgress(show: Boolean) {
-        homeworkProgress.visibility = if (show) View.VISIBLE else View.GONE
+        homeworkProgress.visibility = if (show) VISIBLE else GONE
     }
 
     override fun enableSwipe(enable: Boolean) {
@@ -93,15 +106,15 @@ class HomeworkFragment : BaseFragment(), HomeworkView, MainView.TitledView {
     }
 
     override fun showContent(show: Boolean) {
-        homeworkRecycler.visibility = if (show) View.VISIBLE else View.GONE
+        homeworkRecycler.visibility = if (show) VISIBLE else GONE
     }
 
     override fun showPreButton(show: Boolean) {
-        homeworkPreviousButton.visibility = if (show) View.VISIBLE else View.INVISIBLE
+        homeworkPreviousButton.visibility = if (show) VISIBLE else View.INVISIBLE
     }
 
     override fun showNextButton(show: Boolean) {
-        homeworkNextButton.visibility = if (show) View.VISIBLE else View.INVISIBLE
+        homeworkNextButton.visibility = if (show) VISIBLE else View.INVISIBLE
     }
 
     override fun showTimetableDialog(homework: Homework) {

app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkPresenter.kt

@@ -35,10 +35,13 @@ class HomeworkPresenter @Inject constructor(
     lateinit var currentDate: LocalDate
         private set
 
+    private lateinit var lastError: Throwable
+
     fun onAttachView(view: HomeworkView, date: Long?) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Homework view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData(ofEpochDay(date ?: baseDate.toEpochDay()))
         if (currentDate.isHolidays) setBaseDateOnHolidays()
         reloadView()
@@ -59,6 +62,18 @@ class HomeworkPresenter @Inject constructor(
         loadData(currentDate, true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(currentDate, true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onHomeworkItemSelected(item: AbstractFlexibleItem<*>?) {
         if (item is HomeworkItem) {
             Timber.i("Select homework item ${item.homework.id}")
@@ -105,17 +120,29 @@ class HomeworkPresenter @Inject constructor(
                     view?.apply {
                         updateData(it)
                         showEmpty(it.isEmpty())
+                        showErrorView(false)
                         showContent(it.isNotEmpty())
                     }
                     analytics.logEvent("load_homework", "items" to it.size, "force_refresh" to forceRefresh)
                 }) {
                     Timber.i("Loading homework result: An exception occurred")
-                    view?.run { showEmpty(isViewEmpty()) }
+
                     errorHandler.dispatch(it)
                 })
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     private fun createHomeworkItem(items: Map<LocalDate, List<Homework>>): List<HomeworkItem> {
         return items.flatMap {
             HomeworkHeader(it.key).let { header ->
@@ -131,6 +158,7 @@ class HomeworkPresenter @Inject constructor(
             enableSwipe(false)
             showContent(false)
             showEmpty(false)
+            showErrorView(false)
             clearData()
             reloadNavigation()
         }

app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkView.kt

@@ -5,6 +5,8 @@ import io.github.wulkanowy.ui.base.BaseView
 
 interface HomeworkView : BaseView {
 
+    val isViewEmpty: Boolean
+
     fun initView()
 
     fun updateData(data: List<HomeworkItem>)
@@ -13,12 +15,14 @@ interface HomeworkView : BaseView {
 
     fun updateNavigationWeek(date: String)
 
-    fun isViewEmpty(): Boolean
-
     fun hideRefresh()
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/login/form/LoginFormFragment.kt

@@ -16,7 +16,7 @@ import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.modules.login.LoginActivity
 import io.github.wulkanowy.utils.AppInfo
 import io.github.wulkanowy.utils.hideSoftInput
-import io.github.wulkanowy.utils.openEmail
+import io.github.wulkanowy.utils.openEmailClient
 import io.github.wulkanowy.utils.openInternetBrowser
 import io.github.wulkanowy.utils.showSoftInput
 import kotlinx.android.synthetic.main.fragment_login_form.*
@@ -62,7 +62,7 @@ class LoginFormFragment : BaseFragment(), LoginFormView {
         loginFormHost.setOnItemClickListener { _, _, _, _ -> presenter.onHostSelected() }
         loginFormSignIn.setOnClickListener { presenter.onSignInClick() }
         loginFormPrivacyLink.setOnClickListener { presenter.onPrivacyLinkClick() }
-        loginFormContactDiscord.setOnClickListener { presenter.onDiscordClick() }
+        loginFormFaq.setOnClickListener { presenter.onFaqClick() }
         loginFormContactEmail.setOnClickListener { presenter.onEmailClick() }
 
         loginFormPass.setOnEditorActionListener { _, id, _ ->
@@ -161,12 +161,12 @@ class LoginFormFragment : BaseFragment(), LoginFormView {
         presenter.onDetachView()
     }
 
-    override fun openDiscordInvite() {
+    override fun openFaqPage() {
-        context?.openInternetBrowser("https://discord.gg/vccAQBr", ::showMessage)
+        context?.openInternetBrowser("https://wulkanowy.github.io/czesto-zadawane-pytania/dlaczego-nie-moge-sie-zalogowac", ::showMessage)
     }
 
     override fun openEmail() {
-        context?.openEmail(
+        context?.openEmailClient(
             requireContext().getString(R.string.login_email_intent_title),
             "wulkanowyinc@gmail.com",
             requireContext().getString(R.string.login_email_subject),

app/src/main/java/io/github/wulkanowy/ui/modules/login/form/LoginFormPresenter.kt

@@ -91,8 +91,8 @@ class LoginFormPresenter @Inject constructor(
             }))
     }
 
-    fun onDiscordClick() {
+    fun onFaqClick() {
-        view?.openDiscordInvite()
+        view?.openFaqPage()
     }
 
     fun onEmailClick() {

app/src/main/java/io/github/wulkanowy/ui/modules/login/form/LoginFormView.kt

@@ -45,7 +45,7 @@ interface LoginFormView : BaseView {
 
     fun showContact(show: Boolean)
 
-    fun openDiscordInvite()
+    fun openFaqPage()
 
     fun openEmail()
 }

app/src/main/java/io/github/wulkanowy/ui/modules/login/studentselect/LoginStudentSelectFragment.kt

@@ -14,7 +14,7 @@ import io.github.wulkanowy.data.db.entities.Student
 import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.modules.main.MainActivity
 import io.github.wulkanowy.utils.AppInfo
-import io.github.wulkanowy.utils.openEmail
+import io.github.wulkanowy.utils.openEmailClient
 import io.github.wulkanowy.utils.openInternetBrowser
 import io.github.wulkanowy.utils.setOnItemClickListener
 import kotlinx.android.synthetic.main.fragment_login_student_select.*
@@ -102,7 +102,7 @@ class LoginStudentSelectFragment : BaseFragment(), LoginStudentSelectView {
     }
 
     override fun openEmail() {
-        context?.openEmail(
+        context?.openEmailClient(
             requireContext().getString(R.string.login_email_intent_title),
             "wulkanowyinc@gmail.com",
             requireContext().getString(R.string.login_email_subject),

app/src/main/java/io/github/wulkanowy/ui/modules/login/symbol/LoginSymbolFragment.kt

@@ -16,7 +16,7 @@ import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.modules.login.LoginActivity
 import io.github.wulkanowy.utils.AppInfo
 import io.github.wulkanowy.utils.hideSoftInput
-import io.github.wulkanowy.utils.openEmail
+import io.github.wulkanowy.utils.openEmailClient
 import io.github.wulkanowy.utils.openInternetBrowser
 import io.github.wulkanowy.utils.showSoftInput
 import kotlinx.android.synthetic.main.fragment_login_symbol.*
@@ -50,7 +50,7 @@ class LoginSymbolFragment : BaseFragment(), LoginSymbolView {
 
     override fun initView() {
         loginSymbolSignIn.setOnClickListener { presenter.attemptLogin(loginSymbolName.text.toString()) }
-        loginSymbolContactDiscord.setOnClickListener { presenter.onDiscordClick() }
+        loginSymbolFaq.setOnClickListener { presenter.onFaqClick() }
         loginSymbolContactEmail.setOnClickListener { presenter.onEmailClick() }
 
         loginSymbolName.doOnTextChanged { _, _, _, _ -> presenter.onSymbolTextChanged() }
@@ -126,12 +126,12 @@ class LoginSymbolFragment : BaseFragment(), LoginSymbolView {
         presenter.onDetachView()
     }
 
-    override fun openDiscordInvite() {
+    override fun openFaqPage() {
-        context?.openInternetBrowser("https://discord.gg/vccAQBr", ::showMessage)
+        context?.openInternetBrowser("https://wulkanowy.github.io/czesto-zadawane-pytania/co-to-jest-symbol", ::showMessage)
     }
 
     override fun openEmail() {
-        context?.openEmail(
+        context?.openEmailClient(
             requireContext().getString(R.string.login_email_intent_title),
             "wulkanowyinc@gmail.com",
             requireContext().getString(R.string.login_email_subject),

app/src/main/java/io/github/wulkanowy/ui/modules/login/symbol/LoginSymbolPresenter.kt

@@ -89,8 +89,8 @@ class LoginSymbolPresenter @Inject constructor(
         }
     }
 
-    fun onDiscordClick() {
+    fun onFaqClick() {
-        view?.openDiscordInvite()
+        view?.openFaqPage()
     }
 
     fun onEmailClick() {

app/src/main/java/io/github/wulkanowy/ui/modules/login/symbol/LoginSymbolView.kt

@@ -29,7 +29,7 @@ interface LoginSymbolView : BaseView {
 
     fun showContact(show: Boolean)
 
-    fun openDiscordInvite()
+    fun openFaqPage()
 
     fun openEmail()
 }

app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/LuckyNumberFragment.kt

@@ -3,6 +3,8 @@ package io.github.wulkanowy.ui.modules.luckynumber
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
+import android.view.View.GONE
+import android.view.View.VISIBLE
 import android.view.ViewGroup
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.db.entities.LuckyNumber
@@ -23,17 +25,22 @@ class LuckyNumberFragment : BaseFragment(), LuckyNumberView, MainView.TitledView
     override val titleStringId: Int
         get() = R.string.lucky_number_title
 
+    override val isViewEmpty get() = luckyNumberText.text.isBlank()
+
     override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
         return inflater.inflate(R.layout.fragment_lucky_number, container, false)
     }
 
     override fun onActivityCreated(savedInstanceState: Bundle?) {
         super.onActivityCreated(savedInstanceState)
+        messageContainer = luckyNumberSwipe
         presenter.onAttachView(this)
     }
 
     override fun initView() {
         luckyNumberSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        luckyNumberErrorRetry.setOnClickListener { presenter.onRetry() }
+        luckyNumberErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun updateData(data: LuckyNumber) {
@@ -45,11 +52,19 @@ class LuckyNumberFragment : BaseFragment(), LuckyNumberView, MainView.TitledView
     }
 
     override fun showEmpty(show: Boolean) {
-        luckyNumberEmpty.visibility = if (show) View.VISIBLE else View.GONE
+        luckyNumberEmpty.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun showErrorView(show: Boolean) {
+        luckyNumberError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        luckyNumberErrorMessage.text = message
     }
 
     override fun showProgress(show: Boolean) {
-        luckyNumberProgress.visibility = if (show) View.VISIBLE else View.GONE
+        luckyNumberProgress.visibility = if (show) VISIBLE else GONE
     }
 
     override fun enableSwipe(enable: Boolean) {
@@ -57,11 +72,7 @@ class LuckyNumberFragment : BaseFragment(), LuckyNumberView, MainView.TitledView
     }
 
     override fun showContent(show: Boolean) {
-        luckyNumberContent.visibility = if (show) View.VISIBLE else View.GONE
+        luckyNumberContent.visibility = if (show) VISIBLE else GONE
-    }
-
-    override fun isViewEmpty(): Boolean {
-        return luckyNumberText.text.isBlank()
     }
 
     override fun onDestroyView() {

app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/LuckyNumberPresenter.kt

@@ -19,6 +19,8 @@ class LuckyNumberPresenter @Inject constructor(
     private val analytics: FirebaseAnalyticsHelper
 ) : BasePresenter<LuckyNumberView>(errorHandler, studentRepository, schedulers) {
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: LuckyNumberView) {
         super.onAttachView(view)
         view.run {
@@ -27,6 +29,7 @@ class LuckyNumberPresenter @Inject constructor(
             enableSwipe(false)
         }
         Timber.i("Lucky number view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData()
     }
 
@@ -52,25 +55,49 @@ class LuckyNumberPresenter @Inject constructor(
                         updateData(it)
                         showContent(true)
                         showEmpty(false)
+                        showErrorView(false)
                     }
                     analytics.logEvent("load_lucky_number", "lucky_number" to it.luckyNumber, "force_refresh" to forceRefresh)
                 }, {
                     Timber.i("Loading lucky number result: An exception occurred")
-                    view?.run { showEmpty(isViewEmpty()) }
                     errorHandler.dispatch(it)
                 }, {
                     Timber.i("Loading lucky number result: No lucky number found")
                     view?.run {
                         showContent(false)
                         showEmpty(true)
+                        showEmpty(false)
                     }
                 })
             )
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     fun onSwipeRefresh() {
         Timber.i("Force refreshing the lucky number")
         loadData(true)
     }
+
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/LuckyNumberView.kt

@@ -5,6 +5,8 @@ import io.github.wulkanowy.ui.base.BaseView
 
 interface LuckyNumberView : BaseView {
 
+    val isViewEmpty: Boolean
+
     fun initView()
 
     fun updateData(data: LuckyNumber)
@@ -13,11 +15,13 @@ interface LuckyNumberView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)
 
     fun showContent(show: Boolean)
-
-    fun isViewEmpty(): Boolean
 }

app/src/main/java/io/github/wulkanowy/ui/modules/luckynumberwidget/LuckyNumberWidgetConfigurePresenter.kt

@@ -58,7 +58,10 @@ class LuckyNumberWidgetConfigurePresenter @Inject constructor(
             .subscribe({
                 when {
                     it.isEmpty() -> view?.openLoginView()
-                    it.size == 1 -> registerStudent(it.single().student)
+                    it.size == 1 -> {
+                        selectedStudent = it.single().student
+                        view?.showThemeDialog()
+                    }
                     else -> view?.updateData(it)
                 }
             }, { errorHandler.dispatch(it) }))

app/src/main/java/io/github/wulkanowy/ui/modules/main/MainActivity.kt

@@ -100,7 +100,7 @@ class MainActivity : BaseActivity<MainPresenter>(), MainView {
     override fun initView() {
         with(mainToolbar) {
             if (SDK_INT >= LOLLIPOP) stateListAnimator = null
-            setBackgroundColor(overlayProvider.get().getSurfaceColorWithOverlayIfNeeded(dpToPx(4f)))
+            setBackgroundColor(overlayProvider.get().compositeOverlayWithThemeSurfaceColorIfNeeded(dpToPx(4f)))
         }
 
         with(mainBottomNav) {
@@ -113,7 +113,7 @@ class MainActivity : BaseActivity<MainPresenter>(), MainView {
             ))
             accentColor = getThemeAttrColor(R.attr.colorPrimary)
             inactiveColor = ColorUtils.setAlphaComponent(getThemeAttrColor(R.attr.colorOnSurface), 153)
-            defaultBackgroundColor = overlayProvider.get().getSurfaceColorWithOverlayIfNeeded(dpToPx(8f))
+            defaultBackgroundColor = overlayProvider.get().compositeOverlayWithThemeSurfaceColorIfNeeded(dpToPx(8f))
             titleState = ALWAYS_SHOW
             currentItem = startMenuIndex
             isBehaviorTranslationEnabled = false

app/src/main/java/io/github/wulkanowy/ui/modules/message/preview/MessagePreviewFragment.kt

@@ -65,6 +65,10 @@ class MessagePreviewFragment : BaseFragment(), MessagePreviewView, MainView.Titl
         presenter.onAttachView(this, (savedInstanceState ?: arguments)?.getLong(MESSAGE_ID_KEY) ?: 0L)
     }
 
+    override fun initView() {
+        messagePreviewErrorDetails.setOnClickListener { presenter.onDetailsClick() }
+    }
+
     override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
         inflater.inflate(R.menu.action_menu_message_preview, menu)
         menuReplyButton = menu.findItem(R.id.messagePreviewMenuReply)
@@ -126,8 +130,16 @@ class MessagePreviewFragment : BaseFragment(), MessagePreviewView, MainView.Titl
         menuDeleteButton?.setTitle(R.string.message_move_to_bin)
     }
 
-    override fun showMessageError() {
+    override fun showErrorView(show: Boolean) {
-        messagePreviewError.visibility = VISIBLE
+        messagePreviewError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        messagePreviewErrorMessage.text = message
+    }
+
+    override fun setErrorRetryCallback(callback: () -> Unit) {
+        messagePreviewErrorRetry.setOnClickListener { callback() }
     }
 
     override fun openMessageReply(message: Message?) {

app/src/main/java/io/github/wulkanowy/ui/modules/message/preview/MessagePreviewPresenter.kt

@@ -23,11 +23,29 @@ class MessagePreviewPresenter @Inject constructor(
 
     private var message: Message? = null
 
+    private lateinit var lastError: Throwable
+
+    private var retryCallback: () -> Unit = {}
+
     fun onAttachView(view: MessagePreviewView, id: Long) {
         super.onAttachView(view)
+        view.initView()
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData(id)
     }
 
+    private fun onMessageLoadRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(messageId)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     private fun loadData(id: Long) {
         Timber.i("Loading message $id preview started")
         messageId = id
@@ -55,7 +73,7 @@ class MessagePreviewPresenter @Inject constructor(
                     analytics.logEvent("load_message_preview", "length" to message.content?.length)
                 }) {
                     Timber.i("Loading message $id preview result: An exception occurred ")
-                    view?.showMessageError()
+                    retryCallback = { onMessageLoadRetry() }
                     errorHandler.dispatch(it)
                 })
         }
@@ -85,6 +103,7 @@ class MessagePreviewPresenter @Inject constructor(
                         showContent(false)
                         showProgress(true)
                         showOptions(false)
+                        showErrorView(false)
                     }
                 }
                 .doFinally {
@@ -97,15 +116,24 @@ class MessagePreviewPresenter @Inject constructor(
                         popView()
                     }
                 }, { error ->
-                    view?.showMessageError()
+                    retryCallback = { onMessageDelete() }
                     errorHandler.dispatch(error)
                 }, {
-                    view?.showMessageError()
+                    view?.showErrorView(true)
                 })
             )
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            lastError = error
+            setErrorDetails(message)
+            showErrorView(true)
+            setErrorRetryCallback { retryCallback() }
+        }
+    }
+
     fun onMessageDelete(): Boolean {
         deleteMessage()
         return true

app/src/main/java/io/github/wulkanowy/ui/modules/message/preview/MessagePreviewView.kt

@@ -9,6 +9,8 @@ interface MessagePreviewView : BaseView {
 
     val deleteMessageSuccessString: String
 
+    fun initView()
+
     fun setSubject(subject: String)
 
     fun setRecipient(recipient: String)
@@ -23,19 +25,23 @@ interface MessagePreviewView : BaseView {
 
     fun showContent(show: Boolean)
 
+    fun notifyParentMessageDeleted(message: Message)
+
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
+    fun setErrorRetryCallback(callback: () -> Unit)
+
     fun showOptions(show: Boolean)
 
     fun setDeletedOptionsLabels()
 
     fun setNotDeletedOptionsLabels()
 
-    fun showMessageError()
-
     fun openMessageReply(message: Message?)
 
     fun openMessageForward(message: Message?)
 
     fun popView()
-
-    fun notifyParentMessageDeleted(message: Message)
 }

app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabFragment.kt

@@ -72,6 +72,8 @@ class MessageTabFragment : BaseFragment(), MessageTabView {
             )
         }
         messageTabSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        messageTabErrorRetry.setOnClickListener { presenter.onRetry() }
+        messageTabErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun updateData(data: List<MessageItem>) {
@@ -102,6 +104,14 @@ class MessageTabFragment : BaseFragment(), MessageTabView {
         messageTabEmpty.visibility = if (show) VISIBLE else INVISIBLE
     }
 
+    override fun showErrorView(show: Boolean) {
+        messageTabError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        messageTabErrorMessage.text = message
+    }
+
     override fun showRefresh(show: Boolean) {
         messageTabSwipe.isRefreshing = show
     }

app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabPresenter.kt

@@ -23,9 +23,12 @@ class MessageTabPresenter @Inject constructor(
 
     lateinit var folder: MessageFolder
 
+    private lateinit var lastError: Throwable
+
     fun onAttachView(view: MessageTabView, folder: MessageFolder) {
         super.onAttachView(view)
         view.initView()
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         this.folder = folder
     }
 
@@ -34,6 +37,18 @@ class MessageTabPresenter @Inject constructor(
         onParentViewLoadData(true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onDeleteMessage() {
         loadData(false)
     }
@@ -78,17 +93,28 @@ class MessageTabPresenter @Inject constructor(
                     view?.run {
                         showEmpty(it.isEmpty())
                         showContent(it.isNotEmpty())
+                        showErrorView(false)
                         updateData(it)
                     }
                     analytics.logEvent("load_messages", "items" to it.size, "folder" to folder.name)
                 }) {
                     Timber.i("Loading $folder message result: An exception occurred")
-                    view?.run { showEmpty(isViewEmpty) }
                     errorHandler.dispatch(it)
                 })
         }
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     private fun updateMessage(message: Message) {
         Timber.i("Attempt to update message ${message.id}")
         disposable.add(messageRepository.updateMessage(message)

app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabView.kt

@@ -26,6 +26,10 @@ interface MessageTabView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showRefresh(show: Boolean)
 
     fun openMessage(messageId: Long)

app/src/main/java/io/github/wulkanowy/ui/modules/mobiledevice/MobileDeviceFragment.kt

@@ -61,6 +61,8 @@ class MobileDeviceFragment : BaseFragment(), MobileDeviceView, MainView.TitledVi
             onDeviceUnregisterListener = presenter::onUnregisterDevice
         }
         mobileDevicesSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        mobileDevicesErrorRetry.setOnClickListener { presenter.onRetry() }
+        mobileDevicesErrorDetails.setOnClickListener { presenter.onDetailsClick() }
         mobileDeviceAddButton.setOnClickListener { presenter.onRegisterDevice() }
     }
 
@@ -105,6 +107,14 @@ class MobileDeviceFragment : BaseFragment(), MobileDeviceView, MainView.TitledVi
         mobileDevicesEmpty.visibility = if (show) VISIBLE else GONE
     }
 
+    override fun showErrorView(show: Boolean) {
+        mobileDevicesError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        mobileDevicesErrorMessage.text = message
+    }
+
     override fun enableSwipe(enable: Boolean) {
         mobileDevicesSwipe.isEnabled = enable
     }

app/src/main/java/io/github/wulkanowy/ui/modules/mobiledevice/MobileDevicePresenter.kt

@@ -20,10 +20,13 @@ class MobileDevicePresenter @Inject constructor(
     private val analytics: FirebaseAnalyticsHelper
 ) : BasePresenter<MobileDeviceView>(errorHandler, studentRepository, schedulers) {
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: MobileDeviceView) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Mobile device view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData()
     }
 
@@ -31,6 +34,18 @@ class MobileDevicePresenter @Inject constructor(
         loadData(true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     private fun loadData(forceRefresh: Boolean = false) {
         Timber.i("Loading mobile devices data started")
         disposable.add(studentRepository.getCurrentStudent()
@@ -51,6 +66,7 @@ class MobileDevicePresenter @Inject constructor(
                     updateData(it)
                     showContent(it.isNotEmpty())
                     showEmpty(it.isEmpty())
+                    showErrorView(false)
                 }
                 analytics.logEvent("load_devices", "items" to it.size, "force_refresh" to forceRefresh)
             }) {
@@ -59,6 +75,17 @@ class MobileDevicePresenter @Inject constructor(
             })
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     fun onRegisterDevice() {
         view?.showTokenDialog()
     }

app/src/main/java/io/github/wulkanowy/ui/modules/mobiledevice/MobileDeviceView.kt

@@ -25,6 +25,10 @@ interface MobileDeviceView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showUndo(position: Int, device: MobileDevice)
 
     fun showTokenDialog()

app/src/main/java/io/github/wulkanowy/ui/modules/mobiledevice/token/MobileDeviceTokenDialog.kt

@@ -12,15 +12,13 @@ import android.view.View.VISIBLE
 import android.view.ViewGroup
 import android.widget.Toast
 import androidx.core.content.getSystemService
-import dagger.android.support.DaggerDialogFragment
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.pojos.MobileDeviceToken
-import io.github.wulkanowy.data.repositories.mobiledevice.MobileDeviceRemote
+import io.github.wulkanowy.ui.base.BaseDialogFragment
-import io.github.wulkanowy.ui.base.BaseActivity
 import kotlinx.android.synthetic.main.dialog_mobile_device.*
 import javax.inject.Inject
 
-class MobileDeviceTokenDialog : DaggerDialogFragment(), MobileDeviceTokenVIew {
+class MobileDeviceTokenDialog : BaseDialogFragment(), MobileDeviceTokenVIew {
 
     @Inject
     lateinit var presenter: MobileDeviceTokenPresenter
@@ -66,6 +64,12 @@ class MobileDeviceTokenDialog : DaggerDialogFragment(), MobileDeviceTokenVIew {
         })
     }
 
+    private fun clickCopy(text: String) {
+        val clip = ClipData.newPlainText("wulkanowy", text)
+        activity?.getSystemService<ClipboardManager>()?.setPrimaryClip(clip)
+        Toast.makeText(context, R.string.all_copied, Toast.LENGTH_LONG).show()
+    }
+
     override fun hideLoading() {
         mobileDeviceDialogProgress.visibility = GONE
     }
@@ -78,30 +82,8 @@ class MobileDeviceTokenDialog : DaggerDialogFragment(), MobileDeviceTokenVIew {
         dismiss()
     }
 
-    override fun showError(text: String, error: Throwable) {
-        showMessage(text)
-    }
-
-    override fun showMessage(text: String) {
-        Toast.makeText(context, text, Toast.LENGTH_LONG).show()
-    }
-
-    override fun showExpiredDialog() {
-        (activity as? BaseActivity<*>)?.showExpiredDialog()
-    }
-
-    override fun openClearLoginView() {
-        (activity as? BaseActivity<*>)?.openClearLoginView()
-    }
-
     override fun onDestroyView() {
         presenter.onDetachView()
         super.onDestroyView()
     }
-
-    fun clickCopy(text: String) {
-        val clip = ClipData.newPlainText("wulkanowy", text)
-        activity?.getSystemService<ClipboardManager>()?.setPrimaryClip(clip)
-        Toast.makeText(context, R.string.all_copied, Toast.LENGTH_LONG).show()
-    }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/note/NoteFragment.kt

@@ -60,6 +60,8 @@ class NoteFragment : BaseFragment(), NoteView, MainView.TitledView {
             )
         }
         noteSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        noteErrorRetry.setOnClickListener { presenter.onRetry() }
+        noteErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun showNoteDialog(note: Note) {
@@ -82,6 +84,14 @@ class NoteFragment : BaseFragment(), NoteView, MainView.TitledView {
         noteEmpty.visibility = if (show) VISIBLE else GONE
     }
 
+    override fun showErrorView(show: Boolean) {
+        noteError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        noteErrorMessage.text = message
+    }
+
     override fun showProgress(show: Boolean) {
         noteProgress.visibility = if (show) VISIBLE else GONE
     }

app/src/main/java/io/github/wulkanowy/ui/modules/note/NotePresenter.kt

@@ -21,10 +21,13 @@ class NotePresenter @Inject constructor(
     private val analytics: FirebaseAnalyticsHelper
 ) : BasePresenter<NoteView>(errorHandler, studentRepository, schedulers) {
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: NoteView) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Note view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData()
     }
 
@@ -33,6 +36,18 @@ class NotePresenter @Inject constructor(
         loadData(true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     private fun loadData(forceRefresh: Boolean = false) {
         Timber.i("Loading note data started")
         disposable.add(studentRepository.getCurrentStudent()
@@ -53,17 +68,28 @@ class NotePresenter @Inject constructor(
                 view?.apply {
                     updateData(it)
                     showEmpty(it.isEmpty())
+                    showErrorView(false)
                     showContent(it.isNotEmpty())
                 }
                 analytics.logEvent("load_note", "items" to it.size, "force_refresh" to forceRefresh)
             }, {
                 Timber.i("Loading note result: An exception occurred")
-                view?.run { showEmpty(isViewEmpty) }
                 errorHandler.dispatch(it)
             })
         )
     }
 
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
+
     fun onNoteItemSelected(item: AbstractFlexibleItem<*>?) {
         if (item is NoteItem) {
             Timber.i("Select note item ${item.note.id}")

app/src/main/java/io/github/wulkanowy/ui/modules/note/NoteView.kt

@@ -18,6 +18,10 @@ interface NoteView : BaseView {
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/school/SchoolFragment.kt

@@ -3,6 +3,8 @@ package io.github.wulkanowy.ui.modules.schoolandteachers.school
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
+import android.view.View.GONE
+import android.view.View.VISIBLE
 import android.view.ViewGroup
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.db.entities.School
@@ -10,8 +12,8 @@ import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.modules.main.MainView
 import io.github.wulkanowy.ui.modules.schoolandteachers.SchoolAndTeachersChildView
 import io.github.wulkanowy.ui.modules.schoolandteachers.SchoolAndTeachersFragment
-import io.github.wulkanowy.utils.dialPhone
+import io.github.wulkanowy.utils.openDialer
-import io.github.wulkanowy.utils.openMapLocation
+import io.github.wulkanowy.utils.openNavigation
 import kotlinx.android.synthetic.main.fragment_school.*
 import javax.inject.Inject
 
@@ -22,6 +24,8 @@ class SchoolFragment : BaseFragment(), SchoolView, MainView.TitledView, SchoolAn
 
     override val titleStringId get() = R.string.school_title
 
+    override val isViewEmpty get() = schoolName.text.isBlank()
+
     companion object {
         fun newInstance() = SchoolFragment()
     }
@@ -37,6 +41,8 @@ class SchoolFragment : BaseFragment(), SchoolView, MainView.TitledView, SchoolAn
 
     override fun initView() {
         schoolSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        schoolErrorRetry.setOnClickListener { presenter.onRetry() }
+        schoolErrorDetails.setOnClickListener { presenter.onDetailsClick() }
 
         schoolAddressButton.setOnClickListener { presenter.onAddressSelected() }
         schoolTelephoneButton.setOnClickListener { presenter.onTelephoneSelected() }
@@ -45,19 +51,27 @@ class SchoolFragment : BaseFragment(), SchoolView, MainView.TitledView, SchoolAn
     override fun updateData(data: School) {
         schoolName.text = data.name
         schoolAddress.text = data.address.ifBlank { "-" }
-        schoolAddressButton.visibility = if (data.address.isNotBlank()) View.VISIBLE else View.GONE
+        schoolAddressButton.visibility = if (data.address.isNotBlank()) VISIBLE else GONE
         schoolTelephone.text = data.contact.ifBlank { "-" }
-        schoolTelephoneButton.visibility = if (data.contact.isNotBlank()) View.VISIBLE else View.GONE
+        schoolTelephoneButton.visibility = if (data.contact.isNotBlank()) VISIBLE else GONE
         schoolHeadmaster.text = data.headmaster
         schoolPedagogue.text = data.pedagogue
     }
 
     override fun showEmpty(show: Boolean) {
-        schoolEmpty.visibility = if (show) View.VISIBLE else View.GONE
+        schoolEmpty.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun showErrorView(show: Boolean) {
+        schoolError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        schoolErrorMessage.text = message
     }
 
     override fun showProgress(show: Boolean) {
-        schoolProgress.visibility = if (show) View.VISIBLE else View.GONE
+        schoolProgress.visibility = if (show) VISIBLE else GONE
     }
 
     override fun enableSwipe(enable: Boolean) {
@@ -65,7 +79,7 @@ class SchoolFragment : BaseFragment(), SchoolView, MainView.TitledView, SchoolAn
     }
 
     override fun showContent(show: Boolean) {
-        schoolContent.visibility = if (show) View.VISIBLE else View.GONE
+        schoolContent.visibility = if (show) VISIBLE else GONE
     }
 
     override fun hideRefresh() {
@@ -86,10 +100,10 @@ class SchoolFragment : BaseFragment(), SchoolView, MainView.TitledView, SchoolAn
     }
 
     override fun openMapsLocation(location: String) {
-        context?.openMapLocation(location)
+        context?.openNavigation(location)
     }
 
     override fun dialPhone(phone: String) {
-        context?.dialPhone(phone)
+        context?.openDialer(phone)
     }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/school/SchoolPresenter.kt

@@ -23,10 +23,13 @@ class SchoolPresenter @Inject constructor(
 
     private var contact: String? = null
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: SchoolView) {
         super.onAttachView(view)
         view.initView()
         Timber.i("School view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData()
     }
 
@@ -34,12 +37,24 @@ class SchoolPresenter @Inject constructor(
         loadData(true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onParentViewLoadData(forceRefresh: Boolean) {
         loadData(forceRefresh)
     }
 
     fun onAddressSelected() {
-        address?.let{ view?.openMapsLocation(it) }
+        address?.let { view?.openMapsLocation(it) }
     }
 
     fun onTelephoneSelected() {
@@ -68,6 +83,7 @@ class SchoolPresenter @Inject constructor(
                     updateData(it)
                     showContent(true)
                     showEmpty(false)
+                    showErrorView(false)
                 }
                 analytics.logEvent("load_school", "force_refresh" to forceRefresh)
             }, {
@@ -76,9 +92,22 @@ class SchoolPresenter @Inject constructor(
             }, {
                 Timber.i("Loading school result: No school info found")
                 view?.run {
-                    showContent(false)
+                    showContent(!isViewEmpty)
-                    showEmpty(true)
+                    showEmpty(isViewEmpty)
+                    showErrorView(false)
                 }
             }))
     }
+
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+                showContent(false)
+            } else showError(message, error)
+        }
+    }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/school/SchoolView.kt

@@ -6,12 +6,18 @@ import io.github.wulkanowy.ui.modules.schoolandteachers.SchoolAndTeachersChildVi
 
 interface SchoolView : BaseView, SchoolAndTeachersChildView {
 
+    val isViewEmpty: Boolean
+
     fun initView()
 
     fun updateData(data: School)
 
     fun showEmpty(show: Boolean)
 
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
+
     fun showProgress(show: Boolean)
 
     fun enableSwipe(enable: Boolean)

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/teacher/TeacherFragment.kt

@@ -3,6 +3,8 @@ package io.github.wulkanowy.ui.modules.schoolandteachers.teacher
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.View
+import android.view.View.GONE
+import android.view.View.VISIBLE
 import android.view.ViewGroup
 import eu.davidea.flexibleadapter.FlexibleAdapter
 import eu.davidea.flexibleadapter.common.FlexibleItemDecoration
@@ -16,7 +18,8 @@ import io.github.wulkanowy.ui.modules.schoolandteachers.SchoolAndTeachersFragmen
 import kotlinx.android.synthetic.main.fragment_teacher.*
 import javax.inject.Inject
 
-class TeacherFragment : BaseFragment(), TeacherView, MainView.TitledView, SchoolAndTeachersChildView {
+class TeacherFragment : BaseFragment(), TeacherView, MainView.TitledView,
+    SchoolAndTeachersChildView {
 
     @Inject
     lateinit var presenter: TeacherPresenter
@@ -55,6 +58,8 @@ class TeacherFragment : BaseFragment(), TeacherView, MainView.TitledView, School
             )
         }
         teacherSwipe.setOnRefreshListener { presenter.onSwipeRefresh() }
+        teacherErrorRetry.setOnClickListener { presenter.onRetry() }
+        teacherErrorDetails.setOnClickListener { presenter.onDetailsClick() }
     }
 
     override fun updateData(data: List<TeacherItem>) {
@@ -70,11 +75,19 @@ class TeacherFragment : BaseFragment(), TeacherView, MainView.TitledView, School
     }
 
     override fun showEmpty(show: Boolean) {
-        teacherEmpty.visibility = if (show) View.VISIBLE else View.GONE
+        teacherEmpty.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun showErrorView(show: Boolean) {
+        teacherError.visibility = if (show) VISIBLE else GONE
+    }
+
+    override fun setErrorDetails(message: String) {
+        teacherErrorMessage.text = message
     }
 
     override fun showProgress(show: Boolean) {
-        teacherProgress.visibility = if (show) View.VISIBLE else View.GONE
+        teacherProgress.visibility = if (show) VISIBLE else GONE
     }
 
     override fun enableSwipe(enable: Boolean) {
@@ -82,7 +95,7 @@ class TeacherFragment : BaseFragment(), TeacherView, MainView.TitledView, School
     }
 
     override fun showContent(show: Boolean) {
-        teacherRecycler.visibility = if (show) View.VISIBLE else View.GONE
+        teacherRecycler.visibility = if (show) VISIBLE else GONE
     }
 
     override fun hideRefresh() {

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/teacher/TeacherPresenter.kt

@@ -19,10 +19,13 @@ class TeacherPresenter @Inject constructor(
     private val analytics: FirebaseAnalyticsHelper
 ) : BasePresenter<TeacherView>(errorHandler, studentRepository, schedulers) {
 
+    private lateinit var lastError: Throwable
+
     override fun onAttachView(view: TeacherView) {
         super.onAttachView(view)
         view.initView()
         Timber.i("Teacher view was initialized")
+        errorHandler.showErrorMessage = ::showErrorViewOnError
         loadData()
     }
 
@@ -30,6 +33,18 @@ class TeacherPresenter @Inject constructor(
         loadData(true)
     }
 
+    fun onRetry() {
+        view?.run {
+            showErrorView(false)
+            showProgress(true)
+        }
+        loadData(true)
+    }
+
+    fun onDetailsClick() {
+        view?.showErrorDetailsDialog(lastError)
+    }
+
     fun onParentViewLoadData(forceRefresh: Boolean) {
         loadData(forceRefresh)
     }
@@ -56,6 +71,7 @@ class TeacherPresenter @Inject constructor(
                     updateData(it)
                     showContent(it.isNotEmpty())
                     showEmpty(it.isEmpty())
+                    showErrorView(false)
                 }
                 analytics.logEvent("load_teachers", "items" to it.size, "force_refresh" to forceRefresh)
             }) {
@@ -63,4 +79,15 @@ class TeacherPresenter @Inject constructor(
                 errorHandler.dispatch(it)
             })
     }
+
+    private fun showErrorViewOnError(message: String, error: Throwable) {
+        view?.run {
+            if (isViewEmpty) {
+                lastError = error
+                setErrorDetails(message)
+                showErrorView(true)
+                showEmpty(false)
+            } else showError(message, error)
+        }
+    }
 }

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/teacher/TeacherView.kt

@@ -27,4 +27,8 @@ interface TeacherView : BaseView, SchoolAndTeachersChildView {
     fun showContent(show: Boolean)
 
     fun showEmpty(show: Boolean)
+
+    fun showErrorView(show: Boolean)
+
+    fun setErrorDetails(message: String)
 }

app/src/main/java/io/github/wulkanowy/ui/modules/settings/SettingsFragment.kt

@@ -5,14 +5,17 @@ import android.content.SharedPreferences
 import android.os.Bundle
 import androidx.preference.Preference
 import androidx.preference.PreferenceFragmentCompat
+import com.yariksoffice.lingver.Lingver
 import dagger.android.support.AndroidSupportInjection
 import io.github.wulkanowy.R
 import io.github.wulkanowy.ui.base.BaseActivity
+import io.github.wulkanowy.ui.base.ErrorDialog
 import io.github.wulkanowy.ui.modules.main.MainView
 import io.github.wulkanowy.utils.AppInfo
 import javax.inject.Inject
 
-class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedPreferenceChangeListener,
+class SettingsFragment : PreferenceFragmentCompat(),
+    SharedPreferences.OnSharedPreferenceChangeListener,
     MainView.TitledView, SettingsView {
 
     @Inject
@@ -21,6 +24,9 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
     @Inject
     lateinit var appInfo: AppInfo
 
+    @Inject
+    lateinit var lingver: Lingver
+
     companion object {
         fun newInstance() = SettingsFragment()
     }
@@ -50,6 +56,10 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
         activity?.recreate()
     }
 
+    override fun updateLanguage(langCode: String) {
+        lingver.setLocale(requireContext(), langCode)
+    }
+
     override fun setServicesSuspended(serviceEnablesKey: String, isHolidays: Boolean) {
         findPreference<Preference>(serviceEnablesKey)?.apply {
             summary = if (isHolidays) getString(R.string.pref_services_suspended) else ""
@@ -73,6 +83,10 @@ class SettingsFragment : PreferenceFragmentCompat(), SharedPreferences.OnSharedP
         (activity as? BaseActivity<*>)?.openClearLoginView()
     }
 
+    override fun showErrorDetailsDialog(error: Throwable) {
+        ErrorDialog.newInstance(error).show(childFragmentManager, error.toString())
+    }
+
     override fun onResume() {
         super.onResume()
         preferenceScreen.sharedPreferences.registerOnSharedPreferenceChangeListener(this)