Android MediaPlayer类
阅读原文时间:2021年04月20日阅读:1

1. MediaPlayer方法

  • MediaPlayer创建

    可以直接调用构造函数,利用setDataSource()方法设置资源。

    MediaPlayer mp = new MediaPlayer();
    // path可以是本地路径,也可以是网络地址
    mp.setDataSource(String path);

    也可以调用create()方法,create()方法会直接调用prepare()方法。

    MediaPlayer.create(Context context, int resid)
    MediaPlayer.create(Context context, Uri uri)
  • MediaPlayer的控制方法

    • prepare()/prepareAsync(),提供了同步和异步两种方式设置播放器进入prepare状态
    • start(),启动播放器播放
    • pause(),暂停播放器播放
    • stop(),停止播放器播放
    • getCurrentPosition(),当前播放器的时间
    • seekTo(int),从指定位置开始播放
    • release(),释放播放器暂用资源
    • reset(),是播放器重回到Idle状态
    • setLooping(boolean),设置是否循环播放
  • MediaPlayer的监听器

    • OnPreparedListenerprepare/prepareAsync结束时调用
    • OnCompletionListener,播放结束时调用
    • OnSeekCompleteListenerseekTo(int)结束时调用

2. MediaPlayer状态间的转换

3. MediaPlayer播放音频

onCreate(Bundle)方法中创建MediaPlayer,在onDestroy()方法中销毁。

@Override
protected void onCreate(Bundle savedInstanceState) {
    ... ...

    mMediaPlayer = new MediaPlayer();
    MediaPlayerListener listener = new MediaPlayerListener();
    mMediaPlayer.setOnPreparedListener(listener);
    mMediaPlayer.setOnCompletionListener(listener);
}

@Override
protected void onDestroy() {
    super.onDestroy();
    mMediaPlayer.release();
    mMediaPlayer = null;
}

private void createMediaPlayer() {
    mMediaPlayer.reset();

    try {
        AssetFileDescriptor fd = getAssets().openFd("demo.mp3");
        mMediaPlayer.setDataSource(fd.getFileDescriptor(),
                fd.getStartOffset(), fd.getLength());
        mMediaPlayer.prepare();
        mMediaPlayer.start();
    } catch (IOException e) {
        LogTool.loge(LOG_TAG, e);
    }
}

private void startMediaPlayer() {
    try {
        mMediaPlayer.start();
    } catch (IllegalStateException e) {
        LogTool.loge(LOG_TAG, e);
    }
}

private void pauseMediaPlayer() {
    try  {
        mMediaPlayer.pause();
    } catch (IllegalStateException e) {
        LogTool.loge(LOG_TAG, e);
    }
}

public void stopMediaPlayer() {
    try {
        mMediaPlayer.stop();
    } catch (IllegalStateException e) {
        LogTool.loge(LOG_TAG, e);
    }
}

private class MediaPlayerListener implements MediaPlayer.OnPreparedListener,
        MediaPlayer.OnCompletionListener {

    @Override
    public void onPrepared(MediaPlayer mp) {
    }

    @Override
    public void onCompletion(MediaPlayer mp) {
    }

}

4. MediaPlayer播放视频

MediaPlayer要和SurfaceView配合播放视频,控制的方法和音频相同。
SurfaceViewSurfaceHolder中添加一个回调类Callback,在Callback.surfaceCreated(SurfaceHolder)方法中调用MediaPlayersetDisplay(SurfaceHolder)方法。

@Override
protected void onCreate(Bundle savedInstanceState) {
    ... ...

    SurfaceHolder holder = mSurfaceView.getHolder();
    holder.addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            // createMediaPlayer方法必须要等待Surface被创建以后调用
            createMediaPlayer();
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
        }
    });

    mMediaPlayer = new MediaPlayer();
    MediaPlayerListener listener = new MediaPlayerListener();
    mMediaPlayer.setOnPreparedListener(listener);
    mMediaPlayer.setOnCompletionListener(listener);
}

private void createMediaPlayer() {
    mMediaPlayer.reset();

    try {
        AssetFileDescriptor fd = getAssets().openFd("video.3gp");
        mMediaPlayer.setDataSource(fd.getFileDescriptor(),
                fd.getStartOffset(), fd.getLength());
        mMediaPlayer.prepare();
        mMediaPlayer.setDisplay(mSurfaceView.getHolder());
        mMediaPlayer.start();
    } catch (IOException e) {
    }
}

源码下载: https://github.com/nai-chen/AndroidBlog

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