-Fixed player new share intent causing main player crash due to player activity in background.

app/src/main/java/org/schabi/newpipe/player/BasePlayer.java

@@ -1147,11 +1147,11 @@ public abstract class BasePlayer implements
 
     @Player.RepeatMode
     public int getRepeatMode() {
-        return simpleExoPlayer.getRepeatMode();
+        return simpleExoPlayer == null ? Player.REPEAT_MODE_OFF : simpleExoPlayer.getRepeatMode();
     }
 
     public void setRepeatMode(@Player.RepeatMode final int repeatMode) {
-        simpleExoPlayer.setRepeatMode(repeatMode);
+        if (simpleExoPlayer != null) simpleExoPlayer.setRepeatMode(repeatMode);
     }
 
     public float getPlaybackSpeed() {

app/src/main/java/org/schabi/newpipe/player/MainVideoPlayer.java

@@ -153,7 +153,10 @@ public final class MainVideoPlayer extends AppCompatActivity
     protected void onNewIntent(Intent intent) {
         if (DEBUG) Log.d(TAG, "onNewIntent() called with: intent = [" + intent + "]");
         super.onNewIntent(intent);
-        playerImpl.handleIntent(intent);
+        if (intent != null) {
+            playerState = null;
+            playerImpl.handleIntent(intent);
+        }
     }
 
     @Override