Handle subjects with no attendances in attendance calculator better (#2478)

---------

Co-authored-by: Faierbel <RafalBO99@outlook.com>

app/src/main/java/io/github/wulkanowy/data/Resource.kt

@@ -71,6 +71,9 @@ fun <T, U> Resource<T>.mapData(block: (T) -> U) = when (this) {
     is Resource.Error -> Resource.Error(this.error)
 }
 
+/**
+ * Injects another flow into this flow's resource data.
+ */
 inline fun <T1, T2, R> Flow<Resource<T1>>.combineWithResourceData(
     flow: Flow<T2>,
     crossinline block: suspend (T1, T2) -> R

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

@@ -54,6 +54,15 @@ class PreferencesRepository @Inject constructor(
             context.resources.getString(R.string.pref_default_attendance_calculator_sorting_mode)
         ).asFlow().map(AttendanceCalculatorSortingMode::getByValue)
 
+    /**
+     * Subjects are empty when they don't have any attendances (total = 0, attendances = 0, absences = 0).
+     */
+    val attendanceCalculatorShowEmptySubjects: Flow<Boolean>
+        get() = flowSharedPref.getBoolean(
+            context.getString(R.string.pref_key_attendance_calculator_show_empty_subjects),
+            context.resources.getBoolean(R.bool.pref_default_attendance_calculator_show_empty_subjects)
+        ).asFlow()
+
     private val gradeAverageModePref: Preference<GradeAverageMode>
         get() = getObjectFlow(
             R.string.pref_key_grade_average_mode,

app/src/main/java/io/github/wulkanowy/domain/attendance/GetAttendanceCalculatorDataUseCase.kt

@@ -49,6 +49,9 @@ class GetAttendanceCalculatorDataUseCase @Inject constructor(
                     // intermediates that will be visible for barely any time.
                     .debounceIntermediates()
             }
+            .combineWithResourceData(preferencesRepository.attendanceCalculatorShowEmptySubjects) { attendanceDataList, showEmptySubjects ->
+                attendanceDataList.filter { it.total != 0 || showEmptySubjects }
+            }
             .combineWithResourceData(preferencesRepository.attendanceCalculatorSortingModeFlow, List<AttendanceData>::sortedBy)
 }
 

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

@@ -1,6 +1,5 @@
 package io.github.wulkanowy.ui.modules.attendance.calculator
 
-import android.annotation.SuppressLint
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import androidx.core.view.isVisible
@@ -19,42 +18,47 @@ class AttendanceCalculatorAdapter @Inject constructor() :
 
     override fun getItemCount() = items.size
 
-    override fun onCreateViewHolder(
-        parent: ViewGroup, viewType: Int
-    ) = ViewHolder(
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int) = ViewHolder(
         ItemAttendanceCalculatorHeaderBinding.inflate(
             LayoutInflater.from(parent.context), parent, false
         )
     )
 
-    @SuppressLint("SetTextI18n")
     override fun onBindViewHolder(parent: ViewHolder, position: Int) {
+        val context = parent.binding.root.context
+        val item = items[position]
+
         with(parent.binding) {
-            val item = items[position]
             attendanceCalculatorPercentage.text = "${item.presencePercentage.roundToInt()}"
 
-            if (item.lessonBalance > 0) {
-                attendanceCalculatorSummaryBalance.text = root.context.getString(
-                    R.string.attendance_calculator_summary_balance_positive,
-                    item.lessonBalance
-                )
-            } else if (item.lessonBalance < 0) {
-                attendanceCalculatorSummaryBalance.text = root.context.getString(
-                    R.string.attendance_calculator_summary_balance_negative,
-                    abs(item.lessonBalance)
-                )
-            } else {
-                attendanceCalculatorSummaryBalance.text = root.context.getString(
-                    R.string.attendance_calculator_summary_balance_neutral,
-                )
+            attendanceCalculatorSummaryBalance.text = when {
+                item.lessonBalance > 0 -> {
+                    context.getString(
+                        R.string.attendance_calculator_summary_balance_positive,
+                        item.lessonBalance
+                    )
+                }
+
+                item.lessonBalance < 0 -> {
+                    context.getString(
+                        R.string.attendance_calculator_summary_balance_negative,
+                        abs(item.lessonBalance)
+                    )
+                }
+
+                else -> context.getString(R.string.attendance_calculator_summary_balance_neutral)
             }
             attendanceCalculatorWarning.isVisible = item.lessonBalance < 0
             attendanceCalculatorTitle.text = item.subjectName
-            attendanceCalculatorSummaryValues.text = root.context.getString(
-                R.string.attendance_calculator_summary_values,
-                item.presences,
-                item.total
-            )
+            attendanceCalculatorSummaryValues.text = if (item.total == 0) {
+                context.getString(R.string.attendance_calculator_summary_values_empty)
+            } else {
+                context.getString(
+                    R.string.attendance_calculator_summary_values,
+                    item.presences,
+                    item.total
+                )
+            }
         }
     }
 

app/src/main/res/values/preferences_defaults.xml

@@ -4,6 +4,7 @@
     <bool name="pref_default_attendance_present">true</bool>
     <integer name="pref_default_attendance_target">50</integer>
     <string name="pref_default_attendance_calculator_sorting_mode">alphabetic</string>
+    <bool name="pref_default_attendance_calculator_show_empty_subjects">false</bool>
     <string name="pref_default_grade_average_mode">only_one_semester</string>
     <bool name="pref_default_grade_average_force_calc">false</bool>
     <string name="pref_default_expand_grade_mode">one</string>

app/src/main/res/values/preferences_keys.xml

@@ -4,6 +4,7 @@
     <string name="pref_key_attendance_present">attendance_present</string>
     <string name="pref_key_attendance_target">attendance_target</string>
     <string name="pref_key_attendance_calculator_sorting_mode">attendance_calculator_sorting_mode</string>
+    <string name="pref_key_attendance_calculator_show_empty_subjects">attendance_calculator_show_empty_subjects</string>
     <string name="pref_key_app_theme">app_theme</string>
     <string name="pref_key_dashboard_tiles">dashboard_tiles</string>
     <string name="pref_key_grade_color_scheme">grade_color_scheme</string>

app/src/main/res/values/strings.xml

@@ -263,6 +263,7 @@
     <string name="attendance_calculator_summary_balance_neutral">right on target</string>
     <string name="attendance_calculator_summary_balance_negative"><b>%1$d</b> under target</string>
     <string name="attendance_calculator_summary_values">%1$d/%2$d presences</string>
+    <string name="attendance_calculator_summary_values_empty">No attendances recorded</string>
     <string name="attendance_absence_school">Absent for school reasons</string>
     <string name="attendance_absence_excused">Excused absence</string>
     <string name="attendance_absence_unexcused">Unexcused absence</string>
@@ -721,6 +722,7 @@
     <string name="pref_view_grade_average_force_calc">Force average calculation by app</string>
     <string name="pref_view_present">Show presence</string>
     <string name="pref_attendance_target">Attendance target</string>
+    <string name="pref_attendance_calculator_show_empty_subjects">Show subjects without any attendances</string>
     <string name="pref_view_attendance_calculator_sorting_mode">Attendance calculator sorting</string>
     <string name="pref_view_app_theme">Theme</string>
     <string name="pref_view_expand_grade">Grades expanding</string>

app/src/main/res/xml/scheme_preferences_appearance.xml

@@ -104,6 +104,11 @@
             app:key="@string/pref_key_attendance_calculator_sorting_mode"
             app:title="@string/pref_view_attendance_calculator_sorting_mode"
             app:useSimpleSummaryProvider="true" />
+        <SwitchPreferenceCompat
+            app:defaultValue="@bool/pref_default_attendance_calculator_show_empty_subjects"
+            app:iconSpaceReserved="false"
+            app:key="@string/pref_key_attendance_calculator_show_empty_subjects"
+            app:title="@string/pref_attendance_calculator_show_empty_subjects" />
     </PreferenceCategory>
     <PreferenceCategory
         android:layout_height="wrap_content"