LiveData#getValue can return null

The documentation recommends not calling this method on a background
thread. The problem is that it returns null until the value is set, and
setting the value requires waiting for the set-task to run on the main
thread.

Fixes: 153697933
Test: seek bar is still working
Change-Id: Idbb02e1c9baafd1676f67c1a5408107ed84c41d2

1 files changed, 9 insertions, 4 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/media/SeekBarViewModel.kt b/packages/SystemUI/src/com/android/systemui/media/SeekBarViewModel.kt
index cf8f26841cf9..dd83e42cde2d 100644
--- a/packages/SystemUI/src/com/android/systemui/media/SeekBarViewModel.kt
+++ b/packages/SystemUI/src/com/android/systemui/media/SeekBarViewModel.kt
@@ -34,8 +34,13 @@ private const val POSITION_UPDATE_INTERVAL_MILLIS = 100L
 /** ViewModel for seek bar in QS media player. */
 class SeekBarViewModel(val bgExecutor: DelayableExecutor) {
 
+    private var _data = Progress(false, false, null, null, null)
+        set(value) {
+            field = value
+            _progress.postValue(value)
+        }
     private val _progress = MutableLiveData<Progress>().apply {
-        postValue(Progress(false, false, null, null, null))
+        postValue(_data)
     }
     val progress: LiveData<Progress>
         get() = _progress
@@ -73,7 +78,7 @@ class SeekBarViewModel(val bgExecutor: DelayableExecutor) {
         val position = playbackState?.position?.toInt()
         val duration = mediaMetadata?.getLong(MediaMetadata.METADATA_KEY_DURATION)?.toInt()
         val enabled = if (duration != null && duration <= 0) false else true
-        _progress.postValue(Progress(enabled, seekAvailable, position, duration, color))
+        _data = Progress(enabled, seekAvailable, position, duration, color)
         if (shouldPollPlaybackPosition()) {
             checkPlaybackPosition()
         }
@@ -82,8 +87,8 @@ class SeekBarViewModel(val bgExecutor: DelayableExecutor) {
     @AnyThread
     private fun checkPlaybackPosition(): Runnable = bgExecutor.executeDelayed({
         val currentPosition = controller?.playbackState?.position?.toInt()
-        if (currentPosition != null && _progress.value!!.elapsedTime != currentPosition) {
-            _progress.postValue(_progress.value!!.copy(elapsedTime = currentPosition))
+        if (currentPosition != null && _data.elapsedTime != currentPosition) {
+            _data = _data.copy(elapsedTime = currentPosition)
         }
         if (shouldPollPlaybackPosition()) {
             checkPlaybackPosition()