Disables play/pause button when there's nothing to play

PiperOrigin-RevId: 502571320
(cherry picked from commit 345f2345)

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

@@ -986,6 +986,9 @@ public class StyledPlayerControlView extends FrameLayout {
       ((ImageView) playPauseButton)
       ((ImageView) playPauseButton)
           .setImageDrawable(getDrawable(getContext(), resources, drawableRes));
           .setImageDrawable(getDrawable(getContext(), resources, drawableRes));
       playPauseButton.setContentDescription(resources.getString(stringRes));
       playPauseButton.setContentDescription(resources.getString(stringRes));
+
+      boolean enablePlayPause = shouldEnablePlayPauseButton();
+      updateButton(enablePlayPause, playPauseButton);
     }
     }
   }
   }
 
 
@@ -1503,6 +1506,10 @@ public class StyledPlayerControlView extends FrameLayout {
     }
     }
   }
   }
 
 
+  private boolean shouldEnablePlayPauseButton() {
+    return player != null && !player.getCurrentTimeline().isEmpty();
+  }
+
   private boolean shouldShowPauseButton() {
   private boolean shouldShowPauseButton() {
     return player != null
     return player != null
         && player.getPlaybackState() != Player.STATE_ENDED
         && player.getPlaybackState() != Player.STATE_ENDED