在android中投射时在onstatusUpdated（）中获取媒体状态时出现空指针异常

Question

我在第一次投射时在RemoteMediaPlayer 的onstatusUpdated() 方法中获取媒体状态时得到NullPointerException。如何解决这个问题，我想知道

mRemoteMediaPlayer.requestStatus(mApiClient).setResultCallback(new ResultCallback<RemoteMediaPlayer.MediaChannelResult>(){});

但在使用不同媒体进行第二次投射时效果很好，同时保持同一 chromecast 设备的会话。

mRemoteMediaPlayer.setOnStatusUpdatedListener(new RemoteMediaPlayer.OnStatusUpdatedListener() {

    @Override
    public void onStatusUpdated() {
        MediaStatus mediaStatus = mRemoteMediaPlayer.getMediaStatus();
        MediaInfo mediaInfo = mRemoteMediaPlayer.getMediaInfo();

        RemoteisPlaying = mediaStatus.getPlayerState() == MediaStatus.PLAYER_STATE_PLAYING;                                                 
    }
});

Answer 1

只需用简单的空指针检查包围您的代码，如下所示：

mRemoteMediaPlayer.setOnStatusUpdatedListener(new RemoteMediaPlayer.OnStatusUpdatedListener() {

@Override
public void onStatusUpdated() {
    MediaStatus mediaStatus;
    MediaInfo mediaInfo;
    if(mRemoteMediaPlayer!=null){
        mediaStatus = mRemoteMediaPlayer.getMediaStatus();
        mediaInfo = mRemoteMediaPlayer.getMediaInfo();
        if(mediaStatus!=null){
            //you could even check if mediaStatus.getPlayerState() is not null here
            //before the next line of code
            RemoteisPlaying = mediaStatus.getPlayerState() == MediaStatus.PLAYER_STATE_PLAYING;         
        }
    }                                                
}
});