android - Android服务的生命周期

Question

我试图了解服务在 Android 中的工作方式并阅读 Android 文档以了解绑定(bind)服务: http://developer.android.com/guide/components/bound-services.html对于以后的项目，我需要一个持续在后台运行并且可以通过应用程序与之交互的服务。文档指出您还可以绑定(bind)到已由 startService() 启动的服务。但是，我无法让它正常工作。

服务很简单。它的唯一目的是提供一个计数器(我跳过了导入，以免不必要地弄乱代码):

package com.test.servicetester;

public class LocalService extends Service {
private final IBinder mBinder = new LocalBinder();

private int mCounter = 0;

public class LocalBinder extends Binder {
    LocalService getService() {
        // Return this instance of LocalService so clients can call public methods
        return LocalService.this;
    }
}

private void createNotification(){

    Intent intent = new Intent(this, MainActivity.class);
    PendingIntent pIntent = PendingIntent.getActivity(this, 0, intent, 0);

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this)
        .setSmallIcon(R.drawable.roll)
        .setContentTitle("my notification")
        .setContentText("Hello World!")
        .setProgress(100, 33, false)
        .setOngoing(true)
        .addAction(R.drawable.roll, "Titel", pIntent);

    NotificationManager mNotificationManager = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    mNotificationManager.notify(1337, mBuilder.build());
}

@Override
public void onStart(Intent intent, int startId){
    createNotification();
}

@Override
public IBinder onBind(Intent intent) {
    //createNotification();
    Toast.makeText(this, "The service has been bound.", Toast.LENGTH_SHORT).show();
    return mBinder;
}

/** method for clients */
public int getNumber() {
    mCounter++;
    return mCounter;
}

@Override
public void onDestroy(){
    NotificationManager mNotificationManager = (NotificationManager)getSystemService(Context.NOTIFICATION_SERVICE);
    mNotificationManager.cancelAll();
}
}

我控制服务的 Activity 包含两个按钮，一个用于获取随机数，另一个用于终止服务:

package com.wursti.servicetest0r;

import com.wursti.servicetest0r.LocalService.LocalBinder;

public class MainActivity extends Activity {

LocalService mService;
boolean mBound = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}

@Override
protected void onStart(){
    super.onStart();
    // bind to local service
    if(!isServiceRunning())
        startService(new Intent(this,LocalService.class));
    else
        Toast.makeText(this, "Service is already running.", Toast.LENGTH_SHORT).show();

    Intent intent = new Intent(this, LocalService.class);
    bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
}

private boolean isServiceRunning(){
    ActivityManager manager = (ActivityManager)getSystemService(Context.ACTIVITY_SERVICE);
    for(RunningServiceInfo service : manager.getRunningServices(Integer.MAX_VALUE)) {
        if(LocalService.class.getName().equals(service.service.getClassName())) {
            return true;
        }
    }
    return false;
}

@Override
protected void onStop() {
    super.onStop();
    // unbind from the service
    if(mBound) {
        unbindService(mConnection);
        mBound = false;
    }
}

public void onButtonClick(View v) {
    if(mBound) {
        int num = mService.getNumber();
        Toast.makeText(this, "number: " + num, Toast.LENGTH_SHORT).show();
    }
}

public void onKillServiceClick(View v) {
    mBound = false; // <-- this line was edited because of a comment
    stopService(new Intent(this, LocalService.class));
    unbindService(mConnection);
}

/** 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
        LocalBinder binder = (LocalBinder) service;
        mService = binder.getService();
        mBound = true;
    }

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

发生的事情如下:我启动应用程序并启动服务并出现通知。如果我单击适当的按钮，我会得到正确计数的数字。我可以切换回启动器，重新打开应用程序，然后会收到一条消息，表明服务已经启动并已成功绑定(bind)。但是，如果我单击终止服务按钮，通知会消失，但如果我使用其他按钮，我仍然可以从服务中获取号码。这让我感到困惑......通知在服务 onDestroy() 方法中被销毁。因此它不应该再存在了？为什么它还能提供数字？在终止服务后，如果我切换回启动器，应用程序崩溃并且 logcat 显示:

07-05 10:44:21.964: E/AndroidRuntime(792): java.lang.RuntimeException: Unable to stop activity {com.wursti.servicetest0r/com.wursti.servicetest0r.MainActivity}: java.lang.IllegalArgumentException: Service not registered: com.wursti.servicetest0r.MainActivity$1@40e81200
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3415)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ActivityThread.handleDestroyActivity(ActivityThread.java:3469)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ActivityThread.access$1200(ActivityThread.java:141)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1287)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.os.Handler.dispatchMessage(Handler.java:99)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.os.Looper.loop(Looper.java:137)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ActivityThread.main(ActivityThread.java:5041)
07-05 10:44:21.964: E/AndroidRuntime(792):  at java.lang.reflect.Method.invokeNative(Native Method)
07-05 10:44:21.964: E/AndroidRuntime(792):  at java.lang.reflect.Method.invoke(Method.java:511)
07-05 10:44:21.964: E/AndroidRuntime(792):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-05 10:44:21.964: E/AndroidRuntime(792):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-05 10:44:21.964: E/AndroidRuntime(792):  at dalvik.system.NativeStart.main(Native Method)
07-05 10:44:21.964: E/AndroidRuntime(792): Caused by: java.lang.IllegalArgumentException: Service not registered: com.wursti.servicetest0r.MainActivity$1@40e81200
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.LoadedApk.forgetServiceDispatcher(LoadedApk.java:921)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ContextImpl.unbindService(ContextImpl.java:1451)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.content.ContextWrapper.unbindService(ContextWrapper.java:484)
07-05 10:44:21.964: E/AndroidRuntime(792):  at com.wursti.servicetest0r.MainActivity.onStop(MainActivity.java:61)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1205)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.Activity.performStop(Activity.java:5246)
07-05 10:44:21.964: E/AndroidRuntime(792):  at android.app.ActivityThread.performDestroyActivity(ActivityThread.java:3410)
07-05 10:44:21.964: E/AndroidRuntime(792):  ... 11 more

老实说，我不知道如何从这里继续，感谢任何帮助:)

Answer 1

unbindService(mConnection);

in onStop 即使在您之前终止服务之后也会被调用。

可能就是这个错误。

尝试处理它!!