Android MediaPlayer
1. MediaPlayer播放流程
下面是在Java中调用MediaPlayer实现播放的简单流程
mMediaPlayer.setDataSource(filePath);
mMediaPlayer.prepare();
mDuration.setText(String.valueOf(mMediaPlayer.getDuration()));
mVideoWidht = mMediaPlayer.getVideoWidth();
mVideoHeight = mMediaPlayer.getVideoHeight();
if( mVideoWidht!=0 && mVideoHeight != 0 )
{
mMediaPlayer.start();
}
2. MediaPlayer状态转移图
椭圆：状态
箭头：操作
单箭头-->同步操作
双箭头-->>异步操作
2.1 IdleState 和 EndState
IdleState : new 或者 reset()之后
EndState：release()之后
在IdleState 和 EndState状态中不能调用getCurrentPosition(), getDuration(), getVideoHeight(), getVideoWidth(), setAudioStreamType(int), setLooping(boolean), setVolume(float, float), pause(), start(), stop(),seekTo(int), prepare() or prepareAsync()
二者的区别在于调用后的反馈不同:
IdleState: 调用OnErrorListener.onError() ,状态不变
EndState:调用OnErrorListener.onError(),状态变为ErrorState
2.2 stop
在调用stop后必须调用prepare() or prepareAsync() 才能进入started状态
2.3 prepare() prepareAsync()
作用:预处理播放器为播放做准备
二者的不同在于
prepare:同步操作
prepareAsync:异步操作, 常用用于数据源为流; prepareAsync给出的错误信息也更多
2.4 Completed State
播放结束后的状态, 其后续的状态转移可由setLooping(boolean)设置:
setLooping( true ) : 直接转移到Started状态循环播放
setLooping( false ): 播放完成后触发setOnCompletionListener(OnCompletionListener),
可调用start()重新播放
注意:此时不能调用stop操作, 否则还要进行perpare操作
3. Valid and invalid states
| Method Name | Valid Sates | Invalid States | Comments |
| attachAuxEffect | {Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Idle, Error} | This method must be called after setDataSource. Calling it does not change the object state. |
| getAudioSessionId | any | {} | This method can be called in any state and calling it does not change the object state. |
| getCurrentPosition | {Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| getDuration | {Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Idle, Initialized, Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| getVideoHeight | {Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| getVideoWidth | {Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| isPlaying | {Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| pause | {Started, Paused, PlaybackCompleted} | {Idle, Initialized, Prepared, Stopped, Error} | Successful invoke of this method in a valid state transfers the object to thePaused state. Calling this method in an invalid state transfers the object to the Error state. |
| prepare | {Initialized, Stopped} | {Idle, Prepared, Started, Paused, PlaybackCompleted, Error} | Successful invoke of this method in a valid state transfers the object to thePrepared state. Calling this method in an invalid state throws an IllegalStateException. |
| prepareAsync | {Initialized, Stopped} | {Idle, Prepared, Started, Paused, PlaybackCompleted, Error} | Successful invoke of this method in a valid state transfers the object to thePreparing state. Calling this method in an invalid state throws an IllegalStateException. |
| release | any | {} | After release(), the object is no longer available. |
| reset | {Idle, Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted, Error} | {} | After reset(), the object is like being just created. |
| seekTo | {Prepared, Started, Paused, PlaybackCompleted} | {Idle, Initialized, Stopped, Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| setAudioSessionId | {Idle} | {Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted, Error} | This method must be called in idle state as the audio session ID must be known before calling setDataSource. Calling it does not change the object state. |
| setAudioStreamType | {Idle, Initialized, Stopped, Prepared, Started, Paused, PlaybackCompleted} | {Error} | Successful invoke of this method does not change the state. In order for the target audio stream type to become effective, this method must be called before prepare() or prepareAsync(). |
| setAuxEffectSendLevel | any | {} | Calling this method does not change the object state. |
| setDataSource | {Idle} | {Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted, Error} | Successful invoke of this method in a valid state transfers the object to theInitialized state. Calling this method in an invalid state throws an IllegalStateException. |
| setDisplay | any | {} | This method can be called in any state and calling it does not change the object state. |
| setSurface | any | {} | This method can be called in any state and calling it does not change the object state. |
| setVideoScalingMode | {Initialized, Prepared, Started, Paused, Stopped, PlaybackCompleted} | {Idle, Error} | Successful invoke of this method does not change the state. |
| setLooping | {Idle, Initialized, Stopped, Prepared, Started, Paused, PlaybackCompleted} | {Error} | Successful invoke of this method in a valid state does not change the state. Calling this method in an invalid state transfers the object to theError state. |
| isLooping | any | {} | This method can be called in any state and calling it does not change the object state. |
| setOnBufferingUpdateListener | any | {} | This method can be called in any state and calling it does not change the object state. |
| setOnCompletionListener | any | {} | This method can be called in any state and calling it does not change the object state. |
| setOnErrorListener | any | {} | This method can be called in any state and calling it does not change the object state. |
| setOnPreparedListener | any | {} | This method can be called in any state and calling it does not change the object state. |
| setOnSeekCompleteListener | any | {} | This method can be called in any state and calling it does not change the object state. |
| setScreenOnWhilePlaying | any | {} | This method can be called in any state and calling it does not change the object state. |
| setVolume | {Idle, Initialized, Stopped, Prepared, Started, Paused, PlaybackCompleted} | {Error} | Successful invoke of this method does not change the state. |
| setWakeMode | any | {} | This method can be called in any state and calling it does not change the object state. |
| start | {Prepared, Started, Paused, PlaybackCompleted} | {Idle, Initialized, Stopped, Error} | Successful invoke of this method in a valid state transfers the object to theStarted state. Calling this method in an invalid state transfers the object to the Error state. |
| stop | {Prepared, Started, Stopped, Paused, PlaybackCompleted} | {Idle, Initialized, Error} | Successful invoke of this method in a valid state transfers the object to theStopped state. Calling this method in an invalid state transfers the object to the Error state. |
| getTrackInfo | {Prepared, Started, Stopped, Paused, PlaybackCompleted} | {Idle, Initialized, Error} | Successful invoke of this method does not change the state. |
| addTimedTextSource | {Prepared, Started, Stopped, Paused, PlaybackCompleted} | {Idle, Initialized, Error} | Successful invoke of this method does not change the state. |
| selectTrack | {Prepared, Started, Stopped, Paused, PlaybackCompleted} | {Idle, Initialized, Error} | Successful invoke of this method does not change the state. |
| deselectTrack | {Prepared, Started, Stopped, Paused, PlaybackCompleted} | {Idle, Initialized, Error} | Successful invoke of this method does not change the state. |
4. 参考文献
[1] Android MediaPlayer API http://developer.android.com/reference/android/media/MediaPlayer.html