Prevent using view state and use state saved in fragment instead.

The system may destroy views at any time and may not have created the view
at all. Use the state saved in the fragment to be independant of the existance
of the view.

PiperOrigin-RevId: 234156285

demos/main/src/main/java/com/google/android/exoplayer2/demo/TrackSelectionDialog.java

@@ -145,7 +145,7 @@ public final class TrackSelectionDialog extends DialogFragment {
    */
   public boolean getIsDisabled(int rendererIndex) {
     TrackSelectionViewFragment rendererView = tabFragments.get(rendererIndex);
-    return rendererView != null && rendererView.trackSelectionView.getIsDisabled();
+    return rendererView != null && rendererView.isDisabled;
   }
 
   /**
@@ -157,9 +157,7 @@ public final class TrackSelectionDialog extends DialogFragment {
    */
   public List<SelectionOverride> getOverrides(int rendererIndex) {
     TrackSelectionViewFragment rendererView = tabFragments.get(rendererIndex);
-    return rendererView == null
-        ? Collections.emptyList()
-        : rendererView.trackSelectionView.getOverrides();
+    return rendererView == null ? Collections.emptyList() : rendererView.overrides;
   }
 
   @Override
@@ -269,10 +267,13 @@ public final class TrackSelectionDialog extends DialogFragment {
     private boolean allowAdaptiveSelections;
     private boolean allowMultipleOverrides;
 
-    private boolean isDisabled;
-    private List<SelectionOverride> overrides;
+    /* package */ boolean isDisabled;
+    /* package */ List<SelectionOverride> overrides;
 
-    /* package */ TrackSelectionView trackSelectionView;
+    public TrackSelectionViewFragment() {
+      // Retain instance across orientation changes to prevent loosing access to init data.
+      setRetainInstance(true);
+    }
 
     public void init(
         MappedTrackInfo mappedTrackInfo,
@@ -301,7 +302,8 @@ public final class TrackSelectionDialog extends DialogFragment {
       View rootView =
           inflater.inflate(
               R.layout.track_selection_dialog_tab, container, /* attachToRoot= */ false);
-      trackSelectionView = rootView.findViewById(R.id.download_dialog_track_selection_view);
+      TrackSelectionView trackSelectionView =
+          rootView.findViewById(R.id.download_dialog_track_selection_view);
       trackSelectionView.setShowDisableOption(true);
       trackSelectionView.setAllowMultipleOverrides(allowMultipleOverrides);
       trackSelectionView.setAllowAdaptiveSelections(allowAdaptiveSelections);