带有意图和按钮的Android MediaPlayer错误

Question

基本上，我的主要活动是通过一个意图调用另一个具有应该播放声音的按钮的活动。

也就是说，在第二个活动中我有这个方法：

public void start_sound(View v) {
    String url = /*"MY_URL"*/;
    try {
        if (mp != null)
        {
            mp.stop();
            mp.release();
            mp = null;
        }
        mp = new MediaPlayer();
        mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
        mp.setDataSource(url);
        mp.prepare();
        mp.start();
    } catch (Exception e) {}
}

mp 是一个全局变量（所以我可以检查何时正在播放或为空）。

这是我点击按钮时发生的情况：

E/Surface: getSlotFromBufferLocked: unknown buffer: 0xb40d7400
W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=676.58203, y[0]=318.10547, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=866058, downTime=860523, deviceId=0, source=0x1002 }
W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=676.58203, y[0]=318.10547, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=866058, downTime=860523, deviceId=0, source=0x1002 }
W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=676.58203, y[0]=318.10547, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=866058, downTime=860523, deviceId=0, source=0x1002 }
W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=676.58203, y[0]=318.10547, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=866058, downTime=860523, deviceId=0, source=0x1002 }
E/MediaPlayer: error (1, -2147483648)
I/Choreographer: Skipped 1806 frames!  The application may be doing too much work on its main thread.

第一个发生在我根据意图更改活动时；其他的，当我按下声音按钮时。

我已经拥有清单中的权限。

编辑：这是完整的课程：

import android.media.AudioManager;
import android.media.MediaPlayer;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class activity_2 extends AppCompatActivity {   
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity_2);
    }

    public void start_sound(View v) {

        String url = "<MY_URL>";
        MediaPlayer mp = new MediaPlayer();
        try {
            mp.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mp.setDataSource(url);
            mp.setOnPreparedListener(this);
            mp.prepare();
            mp.start();
        } catch (Exception ignored) {
        }
    }
}

Answer 1

我认为你在初始化之前检查了媒体播放器对象

  if (mp != null)
    {
        mp.stop();
        mp.release();
        mp = null;
    }

确保在使用前初始化媒体播放器对象。

      mp=new MediaPlayer();

 if (mp != null)
    {
        mp.stop();
        mp.release();
        mp = null;
    }

Answer 2

您应该在媒体播放器上使用prepareAsync() 方法，因为您正在播放音乐。只需更改 mp.prepare() 并对其进行测试。

好像你没有实现onPreparedListener。实现这个接口，在onPrepared()里面调用mp.start就可以了。

确保您的第二个活动实现MediaPlayer.OnPreparedListener

您可以实现的其他一些接口是onErrorListener, onCompletionListener

Answer 3

你可以这样做：

public void play(){
    playButton.setImageResource(R.drawable.stop);
    player = new MediaPlayer();
    playing = true;
    player.setWakeMode(context, PowerManager.PARTIAL_WAKE_LOCK);
    player.setAudioStreamType(AudioManager.STREAM_MUSIC);
    player.setOnCompletionListener(this);
    player.setOnErrorListener(this);
    player.setOnPreparedListener(this);
    try {
        player.setDataSource(path);
    } catch (IOException e) {
        e.printStackTrace();
    }
    player.prepareAsync();
}

public void stop(){
    playButton.setImageResource(R.drawable.play);
    playing = false;
    player.stop();
    player.reset();
    player.release();
    player = null;
}

对于我的媒体播放器，我创建了一个自定义侦听器，其中按钮切换播放/停止功能（和图像资源）。 您应该使用 prepareAsync() 并将开始放在 OnPrepared 中。

@Override
public void onClick(View view) {
    if (!playing) {
        play();

    } else {
        stop();

    }
}

@Override
public void onCompletion(MediaPlayer mediaPlayer) {
    playButton.setImageResource(R.drawable.play);
    mediaPlayer.stop();
    mediaPlayer.reset();
    mediaPlayer.release();
    //player = null;
    playing = false;
}

@Override
public boolean onError(MediaPlayer mediaPlayer, int i, int i1) {
    Log.i("Error","found");
    mediaPlayer.stop();
    mediaPlayer.reset();
    mediaPlayer.release();
    //player = null;
    playing = false;
    return false;
}


@Override
public void onPrepared(MediaPlayer mediaPlayer) {
    Log.i("mediaplayer","preparato");
    mediaPlayer.start();

}

如果您在 sd 中播放外部音频，则您遇到的错误是（在我的情况下）连接到不正确的路径，设备没有外部 sd 卡，因此请注意您提供的路径