Fix lifecycle of timer tasks in timetable lessons (#958)

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

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

@@ -1,6 +1,6 @@
 package io.github.wulkanowy.data
 
-data class Resource<out T>(val status: Status, val data: T?, val error: Throwable?) {
+data class Resource<T>(val status: Status, val data: T?, val error: Throwable?) {
     companion object {
         fun <T> success(data: T?): Resource<T> {
             return Resource(Status.SUCCESS, data, null)

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

@@ -6,6 +6,7 @@ import android.view.View.GONE
 import android.view.View.VISIBLE
 import android.view.ViewGroup
 import android.widget.TextView
+import androidx.core.view.ViewCompat
 import androidx.recyclerview.widget.RecyclerView
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.db.entities.Timetable
@@ -44,8 +45,8 @@ class TimetableAdapter @Inject constructor() : RecyclerView.Adapter<RecyclerView
 
     private val timers = mutableMapOf<Int, Timer>()
 
-    private fun resetTimers() {
+    fun resetTimers() {
-        Timber.d("Timetable timers reset")
+        Timber.d("Timetable timers (${timers.size}) reset")
         with(timers) {
             forEach { (_, timer) -> timer.cancel() }
             clear()
@@ -69,11 +70,6 @@ class TimetableAdapter @Inject constructor() : RecyclerView.Adapter<RecyclerView
         }
     }
 
-    override fun onDetachedFromRecyclerView(recyclerView: RecyclerView) {
-        super.onDetachedFromRecyclerView(recyclerView)
-        resetTimers()
-    }
-
     override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
         val lesson = items[position]
 
@@ -112,8 +108,12 @@ class TimetableAdapter @Inject constructor() : RecyclerView.Adapter<RecyclerView
             bindNormalDescription(binding, lesson)
             bindNormalColors(binding, lesson)
 
-            if (lesson.isStudentPlan && showTimers) timers[position] = timer(period = 1000) {
+            if (lesson.isStudentPlan && showTimers) {
-                root.post { updateTimeLeft(binding, lesson, position) }
+                timers[position] = timer(period = 1000) {
+                    if (ViewCompat.isAttachedToWindow(root)) {
+                        root.post { updateTimeLeft(binding, lesson, position) }
+                    }
+                }
             } else {
                 // reset item on set changed
                 timetableItemTimeUntil.visibility = GONE

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

@@ -185,6 +185,7 @@ class TimetableFragment : BaseFragment<FragmentTimetableBinding>(R.layout.fragme
     }
 
     override fun onDestroyView() {
+        timetableAdapter.resetTimers()
         presenter.onDetachView()
         super.onDestroyView()
     }

app/src/main/java/io/github/wulkanowy/utils/FlowUtils.kt

@@ -89,7 +89,7 @@ fun <T> flowWithResourceIn(block: suspend () -> Flow<Resource<T>>) = flow {
                 }
             }
     } catch (e: Throwable) {
-        emit(Resource.error(e))
+        emit(Resource.error<T>(e))
     }
 }
 

build.gradle

@@ -1,6 +1,6 @@
 buildscript {
     ext {
-        kotlin_version = '1.4.0'
+        kotlin_version = '1.4.10'
         about_libraries = '8.3.0'
         hilt_version = "2.29.1-alpha"
     }