[已解决] MediaPlayer.setVolume设置声音大小失效问题

写一个很平常的音乐播放方法，发现声音很小，于是调用MediaPlayer.setVolume来设置声音，结果无效，代码如下：

private static MediaPlayer m = null;

public void play(Context context) {

m = new MediaPlayer();
m = MediaPlayer.create(context, R.raw.myMusic);
m.setAudioStreamType(AudioManager.STREAM_MUSIC);
m.setVolume(1f, 1f);
m.start();

m.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer arg0) {
m.release();
Log.d("MediaPlayer:", "release");
}
});

查找到的解决方法是将setVolume方法放到play之后，如下：

m = new MediaPlayer();
m = MediaPlayer.create(context, R.raw.myMusic);
m.setAudioStreamType(AudioManager.STREAM_MUSIC);
m.start();
m.setVolume(1f, 1f);

再次测试发现声音已经变大，问题解决

查看setVolume源码的注释：

public void setVolume(float leftVolume, float rightVolume)

/**
* Sets the volume on this player.
* This API is recommended for balancing the output of audio streams
* within an application. Unless you are writing an application to
* control user settings, this API should be used in preference to
* {@link AudioManager#setStreamVolume(int, int, int)} which sets the volume of ALL streams of
* a particular type. Note that the passed volume values are raw scalars in range 0.0 to 1.0.
* UI controls should be scaled logarithmically.
*
* @param leftVolume left volume scalar
* @param rightVolume right volume scalar
*/

其中的两个参数分别是左右声道声音大小，取值范围为0~1