java - Android MediaPlayer::问题

Question

我知道这是一个非常常见的问题。但是，尽管我的逻辑是正确的，但我在使用 MediaPlayer 类在我的应用程序中播放声音时遇到了问题。目前，我的应用程序中有震动检测功能。每次摇动设备时，它都应该发出声音。下面是我的代码:

public class MainActivity extends AppCompatActivity {

private SensorManager mSensorManager;
private Sensor mAccelerometer;
private ShakeDetector mShakeDetector;
private SoundManager mSoundManager;
private TextView xText;
private Context context;
private AudioPool ap;
int id1,id2;
File directory;

MediaPlayer player, mPlayer;
AudioCollective ac;
Lagu la;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    xText = (TextView)findViewById(R.id.xText);

    mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mShakeDetector = new ShakeDetector();

   la = new Lagu();
    la.initLagu(MainActivity.this);

    mShakeDetector.setOnShakeListener(new ShakeDetector.OnShakeListener() {

        @Override
        public void onShake(int count) {

            la.playLagu();
            xText.setText("Shake:"+count);

        }
    });
}

public class Lagu {
MediaPlayer mPlayer;
public Lagu(){
    mPlayer = new MediaPlayer();
}
public void initLagu(Context theContext){
    mPlayer.create(theContext, R.raw.na);
}
public void playLagu(){
    mPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
        @Override
        public void onPrepared(MediaPlayer mp) {
            mp.start();
        }
    });
}

}

问题是应用程序不在每次手机摇晃时播放声音。应用程序甚至一次都不会播放声音。仅供引用，歌曲的格式是 MP3。有人请告诉我我的应用程序出了什么问题吗？我们将不胜感激您的帮助!

Answer 1

来自documentation对于Mediaplayer.create():

Convenience method to create a MediaPlayer for a given resource id. On success, prepare() will already have been called and must not be called again.

注意:Mediaplayer.create() 方法是一个静态方法，它返回一个现成的 Mediaplayer。

所以你需要将返回值分配给你的mPlayer您不需要任何 OnPreparedListener - 只需调用 start()

public class Lagu {

MediaPlayer mPlayer;

public Lagu(){
    // do nothing or call initLagu() here
    // in this case skip the method call from the Activity's onCreate()
}

public void initLagu(Context theContext){
    mPlayer = Mediaplayer.create(theContext, R.raw.na);
}

public void playLagu(){

    mPlayer.start(); 
}

}