fix(app): fix removal of delayed callbacks from handlers

calling Handler#removeCallbacks doesn't seem to work with Kotlin's
function references. An additional token can be used to ensure
that callbacks are removed when using function references.

app/src/main/java/com/github/ashutoshgngwr/noice/sound/player/Player.kt

@@ -2,6 +2,7 @@ package com.github.ashutoshgngwr.noice.sound.player
 
 import android.os.Handler
 import android.util.Log
+import androidx.core.os.HandlerCompat
 import com.github.ashutoshgngwr.noice.sound.Sound
 import com.github.ashutoshgngwr.noice.sound.player.strategy.PlaybackStrategy
 import com.github.ashutoshgngwr.noice.sound.player.strategy.PlaybackStrategyFactory
@@ -15,6 +16,7 @@ class Player(private val sound: Sound, playbackStrategyFactory: PlaybackStrategy
 
   companion object {
     private val TAG = Player::class.simpleName
+    private val DELAYED_PLAYBACK_CALLBACK_TOKEN = "${Player::class.simpleName}.playback_callback"
 
     const val DEFAULT_VOLUME = 4
     const val MAX_VOLUME = 20
@@ -64,13 +66,16 @@ class Player(private val sound: Sound, playbackStrategyFactory: PlaybackStrategy
    */
   private fun playAndRegisterDelayedCallback() {
     if (!isPlaying) {
+      Log.d(TAG, "delayed callback invoked but not playing! won't perform playback.")
       return
     }
 
     playbackStrategy.play()
     val delay = nextInt(MIN_TIME_PERIOD, 1 + timePeriod) * 1000L
-    handler.postDelayed(this::playAndRegisterDelayedCallback, delay)
     Log.d(TAG, "scheduling delayed playback with ${delay}ms delay")
+    HandlerCompat.postDelayed(
+      handler, this::playAndRegisterDelayedCallback, DELAYED_PLAYBACK_CALLBACK_TOKEN, delay
+    )
   }
 
   /**
@@ -80,8 +85,8 @@ class Player(private val sound: Sound, playbackStrategyFactory: PlaybackStrategy
   fun pause() {
     isPlaying = false
     playbackStrategy.pause()
-    if (sound.isLoopable) {
-      handler.removeCallbacks(this::playAndRegisterDelayedCallback)
+    if (!sound.isLoopable) {
+      handler.removeCallbacksAndMessages(DELAYED_PLAYBACK_CALLBACK_TOKEN)
     }
   }
 
@@ -92,8 +97,8 @@ class Player(private val sound: Sound, playbackStrategyFactory: PlaybackStrategy
   fun stop() {
     isPlaying = false
     playbackStrategy.stop()
-    if (sound.isLoopable) {
-      handler.removeCallbacks(this::playAndRegisterDelayedCallback)
+    if (!sound.isLoopable) {
+      handler.removeCallbacksAndMessages(DELAYED_PLAYBACK_CALLBACK_TOKEN)
     }
   }
 

app/src/main/java/com/github/ashutoshgngwr/noice/sound/player/PlayerManager.kt

@@ -7,6 +7,7 @@ import android.support.v4.media.MediaMetadataCompat
 import android.support.v4.media.session.MediaSessionCompat
 import android.support.v4.media.session.PlaybackStateCompat
 import android.util.Log
+import androidx.core.os.HandlerCompat
 import androidx.media.AudioAttributesCompat
 import androidx.media.AudioFocusRequestCompat
 import androidx.media.AudioManagerCompat
@@ -33,6 +34,7 @@ class PlayerManager(private val context: Context) :
 
   companion object {
     private val TAG = PlayerManager::javaClass.name
+    private val DELAYED_STOP_CALLBACK_TOKEN = "${PlayerManager::javaClass.name}.stop_callback"
   }
 
   var state = State.STOPPED
@@ -126,7 +128,7 @@ class PlayerManager(private val context: Context) :
         }
       }
       AudioManager.AUDIOFOCUS_LOSS -> {
-        Log.d(TAG, "Permanently lost audio focus! Stop playback...")
+        Log.d(TAG, "Permanently lost audio focus! pause and wait to stop playback...")
         hasAudioFocus = false
         resumeOnFocusGain = true
         playbackDelayed = false
@@ -243,17 +245,21 @@ class PlayerManager(private val context: Context) :
     notifyChanges()
   }
 
-  fun pauseAndWaitBeforeStop() {
+  private fun pauseAndWaitBeforeStop() {
     pause()
-    handler.postDelayed(this::stop, TimeUnit.MINUTES.toMillis(1))
+    Log.d(TAG, "scheduling pauseAndWaitBeforeStop callback")
+    HandlerCompat.postDelayed(
+      handler, this::stop, DELAYED_STOP_CALLBACK_TOKEN, TimeUnit.MINUTES.toMillis(1)
+    )
   }
 
   /**
    * Resumes all [Player]s from the saved state. It requests AudioFocus if not already present.
    */
   fun resume() {
     if (hasAudioFocus) {
-      handler.removeCallbacks(this::stop) // remove pauseAndWaitBeforeStop callbacks, if any
+      Log.d(TAG, "removing pauseAndWaitBeforeStop callback")
+      handler.removeCallbacksAndMessages(DELAYED_STOP_CALLBACK_TOKEN)
       state = State.PLAYING
       players.values.forEach { it.play() }
     } else if (!playbackDelayed) {

app/src/main/java/com/github/ashutoshgngwr/noice/widget/CountdownTextView.kt

@@ -41,13 +41,28 @@ class CountdownTextView : MaterialTextView {
    */
   private var countdownUntilMillis = SystemClock.uptimeMillis()
 
+  /**
+   * Updates the view content and registers a delayed callback to itself for indefinitely refreshing
+   * the view content. Use [android.view.View.removeCallbacks] to remove the callback. If won't
+   * register itself as a delayed callback if countdown timer has finished or if the view is not
+   * attached to a window anymore.
+   */
+  private val updateCallback = object : Runnable {
+    override fun run() {
+      updateCountdown()
+      if (SystemClock.uptimeMillis() < countdownUntilMillis) {
+        postDelayed(this, UPDATE_INTERVAL)
+      }
+    }
+  }
+
   override fun onAttachedToWindow() {
     super.onAttachedToWindow()
-    updateCountdownWithCallbacks()
+    post(updateCallback)
   }
 
   override fun onDetachedFromWindow() {
-    removeCallbacks(this::updateCountdownWithCallbacks)
+    removeCallbacks(updateCallback)
     super.onDetachedFromWindow()
   }
 
@@ -58,22 +73,9 @@ class CountdownTextView : MaterialTextView {
    */
   fun startCountdown(millis: Long) {
     // remove any pre-registered callbacks. startCountdown() may be called multiple times.
-    removeCallbacks(this::updateCountdownWithCallbacks)
+    removeCallbacks(updateCallback)
     countdownUntilMillis = SystemClock.uptimeMillis() + millis
-    updateCountdownWithCallbacks()
-  }
-
-  /**
-   * Updates the view content and registers a delayed callback to itself for indefinitely refreshing
-   * the view content. Use [android.view.View.removeCallbacks] to remove the callback. If won't
-   * register itself as a delayed callback if countdown timer has finished or if the view is not
-   * attached to a window anymore.
-   */
-  private fun updateCountdownWithCallbacks() {
-    updateCountdown()
-    if (SystemClock.uptimeMillis() < countdownUntilMillis) {
-      postDelayed(this::updateCountdownWithCallbacks, UPDATE_INTERVAL)
-    }
+    post(updateCallback)
   }
 
   /**