安卓服务 - 错误 : service not registered

Question

我正在尝试了解有界服务。在我尝试遵循的示例程序下方http://developer.android.com/guide/components/bound-services.html .该服务可以播放、暂停和停止音频，但当我切换到另一个应用程序时，我收到以下服务未注册错误。

java.lang.RuntimeException: Unable to stop activity {com.example.dd_services_audio_01/com.example.dd_services_audio_01.MainActivity}: java.lang.IllegalArgumentException: Service not registered: com.example.dd_services_audio_01.MainActivity$1@2afca5d8
09-05 14:04:32.625: E/AndroidRuntime(5810):     at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:2451)
09-05 14:04:32.625: E/AndroidRuntime(5810):     at android.app.ActivityThread.handleStopActivity(ActivityThread.java:2496)

由于编码似乎与文档示例密切相关，我不知道哪里出了问题。我使用 minSdk 级别 8 运行此应用程序。错误发生在 MainActivity.onStop 行

 mService.unbindService(mConnection);

任何解决这个问题的建议都会很棒。

谢谢

马丁

package com.example.dd_services_audio_01;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.Environment;
import android.os.IBinder;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

import com.example.dd_services_audio_01.AudioPlayerService.AudioPlayerBinder;

public class MainActivity extends Activity {

private final String TAG = "MainActivity";

AudioPlayerService mService;
boolean mBound = false;

Button mPlay, mPause, mStop;

String audioFile = Environment.getExternalStorageDirectory()
        + "/justdzongsar/DJKR_AboutToGetIt.mp3";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Log.d(TAG,"onCreate");
    setContentView(R.layout.activity_main);

    mPlay = (Button) findViewById(R.id.buttonPlay);
    mPause = (Button) findViewById(R.id.buttonPause);
    mStop = (Button) findViewById(R.id.buttonStop);

    mPlay.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            mService.play(audioFile);
        }
    });

    mPause.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            mService.pause();
        }
    });

    mStop.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            mService.stop();
        }
    });

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

@Override
protected void onStart() {
    super.onStart();
    // Bind to LocalService
    Intent intent = new Intent(this, AudioPlayerService.class);
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE);


}

@Override
protected void onStop() {
    super.onStop();

    if (mBound) {
        mService.unbindService(mConnection);
        mBound=false;
    }
} 

/** Defines callbacks for service binding, passed to bindService() */
private ServiceConnection mConnection = new ServiceConnection() {

    @Override
    public void onServiceConnected(ComponentName className, IBinder service) {
        // We've bound to LocalService, cast the IBinder and get
        // LocalService instance
        AudioPlayerBinder binder = (AudioPlayerBinder) service;
        mService = binder.getService();
        mBound = true;
    }

    @Override
    public void onServiceDisconnected(ComponentName arg0) {
        mService = null;
        mBound = false;
    }
};

}

和

package com.example.dd_services_audio_01;

import java.io.IOException;

import android.app.Service;
import android.content.Intent;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.media.MediaPlayer.OnPreparedListener;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;

public class AudioPlayerService extends Service implements OnPreparedListener,
    OnCompletionListener {

private final String TAG = "AudioPlayerService";

private final IBinder mBinder = new AudioPlayerBinder();

private MediaPlayer mMediaPlayer;

private String currentDataSource;

public class AudioPlayerBinder extends Binder {
    public AudioPlayerService getService() {
        Log.v(TAG, "AudioPlayerBinder: getService() called");
        return AudioPlayerService.this;
    }
}

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return mBinder;
}

@Override
public boolean onUnbind(Intent intent) {
    // All clients have unbound with unbindService()
    return false;
}

@Override
public void onStart(Intent intent, int startId) {
    Log.i(TAG,
            "AudioPlayerService: onStart() called, instance="
                    + this.hashCode());
}

@Override
public void onDestroy() {
    Log.i(TAG, "AudioPlayerService: onDestroy() called");
    releaseMediaPlayer();
}

// -----

public void play(String audioFile) {
    Log.d(TAG, "audio play called with file " + audioFile);
    if (mMediaPlayer != null && audioFile.compareTo(currentDataSource) == 0) {
        if (mMediaPlayer.isPlaying() == true) {
            return;
        }
        mMediaPlayer.start();

        return;
    }
    releaseMediaPlayer();

    try {

        mMediaPlayer = new MediaPlayer();
        mMediaPlayer.setDataSource(audioFile);


        mMediaPlayer.setOnPreparedListener(this);
        mMediaPlayer.setOnCompletionListener(this);
        currentDataSource = audioFile;

                    mMediaPlayer.prepareAsync();


    } catch (IOException ioe) {
        Log.e(TAG, "error trying to play " + audioFile, ioe);
    }

}

public void pause() {

    Log.d(TAG, "audio pause");
    if (mMediaPlayer != null && mMediaPlayer.isPlaying()) {
        mMediaPlayer.pause();
    }
}

public void seek(int timeInMillis) {
    if (mMediaPlayer != null) {
        mMediaPlayer.seekTo(timeInMillis);
    }
}

public int elapsed() {
    if (mMediaPlayer == null) {
        return 0;
    }
    return mMediaPlayer.getCurrentPosition();
}

public void stop() {
    Log.d(TAG, "audio stop");
    releaseMediaPlayer();
}

// --

private void releaseMediaPlayer() {
    if (mMediaPlayer == null) {
        return;
    }

    if (mMediaPlayer.isPlaying()) {
        mMediaPlayer.stop();
    }
    mMediaPlayer.release();
    mMediaPlayer = null;
}

@Override
public void onCompletion(MediaPlayer arg0) {
    // TODO Auto-generated method stub
    releaseMediaPlayer();
}

@Override
public void onPrepared(MediaPlayer mp) {
    if (mp != null) {
        mp.start();
    }

    // TODO Auto-generated method stub

}

}

Answer 1

有类似的问题，但接受的答案不是我的解决方案。幸运的是，其中一条评论给了我答案:

onServiceDisconnected is not supposed to be raised when you unbind your service, so don't rely on it. It is supposed to inform you in case the connection between your Service and ServiceConnection is dropped.

感谢@Waqas，我发现了错误:我只在 onServiceConnected() 和 onServiceDisconnected() 中更新了 boolean binded 标志。现在我每次调用 unbindService() 时都添加了“binded=false”，问题就消失了。就是这样，不要依赖onServiceDisconnected