IntentService 在启动时崩溃

Question

我的服务有问题。事实是，当它 strat 时，它会崩溃我的所有应用程序。调试应用程序告诉我它在 "onCreate" 方法结束后崩溃（请参阅下面的代码）。似乎它甚至无法访问 onHandedIntent 但不确定！我把我的代码和日志放在下面。我检查了清单，没有问题。

感谢大家的帮助

package com.example.pierr.puremusictest2;
import android.app.IntentService;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.util.Log;

import java.io.IOException;

public class MusicPlayerService extends IntentService{
static MediaPlayer mPlayer;
Intent gIntent;
String url = "http://lolilol.890m.com/Musique/CapitalKings/II/Capital_Kings_-_Satellites_Official_Audio_Video-r8.aac";

public MusicPlayerService() {
    super("mainThreadService");
    Log.i("blablabblablba","creation that's it2");
}

public void onCreate(){
    Log.i("blablabblablba","creation that's it2");
    mPlayer = new MediaPlayer();
    mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
    Log.i("blablabblablba","musicPlayer created");
}

@Override
protected void onHandleIntent(Intent argo0) {
play();
}


public void play(){
    try {
        Log.i("voila c'est cool","play");
        mPlayer.setDataSource(url);
    } catch (IOException e) {
        e.printStackTrace();

    Log.i("test","destroy");       }
    mPlayer.start();

}

}

开始我的服务的意图：

case R.id.play:
            Intent intent = new Intent(getActivity(), MusicPlayerService.class);
            getActivity().startService(intent);
            break;

最后是日志：

 java.lang.RuntimeException: Unable to start service com.example.pierr.puremusictest2.MusicPlayerService@419ed5d8 with Intent { cmp=com.example.pierr.puremusictest2/.MusicPlayerService }: java.lang.NullPointerException
                                                                                at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2719)
                                                                                at android.app.ActivityThread.access00(ActivityThread.java:135)
                                                                                at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
                                                                                at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                at android.os.Looper.loop(Looper.java:136)
                                                                                at android.app.ActivityThread.main(ActivityThread.java:5027)
                                                                                at java.lang.reflect.Method.invokeNative(Native Method)
                                                                                at java.lang.reflect.Method.invoke(Method.java:515)
                                                                                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
                                                                                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
                                                                                at dalvik.system.NativeStart.main(Native Method)
                                                                             Caused by: java.lang.NullPointerException
                                                                                at android.app.IntentService.onStart(IntentService.java:116)
                                                                                at android.app.IntentService.onStartCommand(IntentService.java:130)
                                                                                at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:2702)
                                                                                at android.app.ActivityThread.access00(ActivityThread.java:135) 
                                                                                at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293) 
                                                                                at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                                at android.os.Looper.loop(Looper.java:136) 
                                                                                at android.app.ActivityThread.main(ActivityThread.java:5027) 
                                                                                at java.lang.reflect.Method.invokeNative(Native Method) 
                                                                                at java.lang.reflect.Method.invoke(Method.java:515) 
                                                                                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
                                                                                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
                                                                                at dalvik.system.NativeStart.main(Native Method)

Answer 1

在您服务的 onCreate() 方法中，先调用 super.onCreate()，然后再执行任何其他操作。

请注意，使用 IntentService 播放音乐是一个相当奇怪的选择：

您的 onHandleIntent() 方法中没有任何内容看起来需要后台线程。
IntentService会被销毁一次onHandleIntent()returns。我忘记了 MediaPlayer 是否会停止播放（一旦丢失的 MediaPlayer 对象被垃圾收集）或者如果你只是失去对播放的控制。

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