Fix StyledPlayerView detachment

Issue: #8985
#minor-release
PiperOrigin-RevId: 375913914

RELEASENOTES.md

@@ -19,6 +19,10 @@
     *   Keep subtitle language features embedded (e.g. rubies & tate-chu-yoko)
         in `Cue.text` even when `SubtitleView#setApplyEmbeddedStyles()` is
         false.
+*   UI
+    *   Fix `NullPointerException` in `StyledPlayerView` that could occur after
+        calling `StyledPlayerView.setPlayer(null)`
+        ([#8985](https://github.com/google/ExoPlayer/issues/8985)).
 
 ### 2.14.0 (2021-05-13)
 

library/ui/src/main/java/com/google/android/exoplayer2/ui/StyledPlayerView.java

@@ -570,6 +570,7 @@ public class StyledPlayerView extends FrameLayout implements AdViewProvider {
     }
     @Nullable Player oldPlayer = this.player;
     if (oldPlayer != null) {
+      oldPlayer.removeListener(componentListener);
       if (surfaceView instanceof TextureView) {
         oldPlayer.clearVideoTextureView((TextureView) surfaceView);
       } else if (surfaceView instanceof SurfaceView) {