code: @SuppressWarnings("deprecation")
      private void initLockScreenRemoteControlClient(Context context) {
          if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
              mMediaButtonReceiverComponent = new ComponentName(
                      mRuntimePackageName, MediaSessionReceiver.class.getName());
              mAudioManager.registerMediaButtonEventReceiver(mMediaButtonReceiverComponent);
  
              if (mRemoteControlClientCompat == null) {
                  Intent remoteControlIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
                  remoteControlIntent.setComponent(mMediaButtonReceiverComponent);
                  mRemoteControlClientCompat = new RemoteControlClientCompat(
                          PendingIntent.getBroadcast(context, 0, remoteControlIntent, 0));
                  RemoteControlHelper.registerRemoteControlClient(mAudioManager, mRemoteControlClientCompat);
  
              }
              mRemoteControlClientCompat.setPlaybackState(RemoteControlClient.PLAYSTATE_PLAYING);
              mRemoteControlClientCompat.setTransportControlFlags(RemoteControlClient.FLAG_KEY_MEDIA_PLAY
                      | RemoteControlClient.FLAG_KEY_MEDIA_PAUSE
                      | RemoteControlClient.FLAG_KEY_MEDIA_NEXT
                      | RemoteControlClient.FLAG_KEY_MEDIA_STOP
                      | RemoteControlClient.FLAG_KEY_MEDIA_PREVIOUS
                      | RemoteControlClient.FLAG_KEY_MEDIA_PLAY_PAUSE);
  
              registerLockScreenReceiver(context);
          }
      }
docs: Initialize the remote control client on the lock screen.
  
  @param context holding context.