问Android本地webrtc:在已连接后添加视频

EN

 public void setVideoEnabled(final boolean enable) {
executor.execute(new Runnable() {
  @Override
  public void run() {
    renderVideo = enable;
    if (localVideoTrack != null) {
      localVideoTrack.setEnabled(renderVideo);
    } else {
      if (renderVideo) {
          //AC: create a video track
          String cameraDeviceName = VideoCapturerAndroid.getDeviceName(0);
          String frontCameraDeviceName =
                  VideoCapturerAndroid.getNameOfFrontFacingDevice();
          if (numberOfCameras > 1 && frontCameraDeviceName != null) {
              cameraDeviceName = frontCameraDeviceName;
          }
          Log.i(TAG, "Opening camera: " + cameraDeviceName);
          videoCapturer = VideoCapturerAndroid.create(cameraDeviceName);
          if (createVideoTrack(videoCapturer) != null) {                
              mediaStream.addTrack(localVideoTrack);
              localVideoTrack.setEnabled(renderVideo);
              peerConnection.addStream(mediaStream);
          } else {
              Log.d(TAG, "Local video track is still null");
          }
      } else {
        Log.d(TAG, "Local video track is null");
      }
    }
    if (remoteVideoTrack != null) {
      remoteVideoTrack.setEnabled(renderVideo);
    } else {
      Log.d(TAG,"Remote video track is null");
    }
  }
});