Question

我有一个Activity，它启动非本地服务。有时我会检查是否还活着。

我此刻的尝试是使用静态布尔变量。阅读SO上的一些帖子我发现这不起作用，因为each process has it's own classloader。

Iterating over all running services做一个像这样的简单任务是很昂贵的。

其他解决方案指出使用AIDL。在我的服务的不久的将来，我将为当前运行的活动存储一个WeakReference，以便在发生崩溃时再次执行它。假设现在我只想检查服务状态，这也是一个昂贵的解决方案吗？

P.S。：我知道这是一个不能正确处理异常的丑陋解决方案。这只是一次尝试。

编辑：为了澄清我在做什么，我发布了一些代码。这是服务类：

public class CrashRecover extends Service {

private volatile boolean stop = false;
private Thread backgroundThread;
private Messenger serviceMessenger = null;
private static boolean running = false;

...

@Override
public int onStartCommand(Intent intent, int flags, int startID){
    serviceMessenger = new Messenger(new ServiceHandler(serviceLooper));
    return START_STICKY;
}

@Override
public void onCreate(){
    super.onCreate();
    HandlerThread handlerThread = new HandlerThread("CrashRecoverThread", Process.THREAD_PRIORITY_BACKGROUND);
    handlerThread.start();

    serviceLooper = handlerThread.getLooper();
    backgroundThread = new Thread(){
        @Override
        public void run(){
            synchronized(this){
                try {
                    while(!stop){
                        sleep(500);
                    }
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }                   
            }
        }
    };
    running = true;
}

@Override
public void onDestroy(){
    super.onDestroy();
    try {
        Message destroyMessage = Message.obtain();
        destroyMessage.arg1 = CrashRecover.DESTROY_SERVICE;
        serviceMessenger.send(destroyMessage);
    } catch (RemoteException e) {
        e.printStackTrace();
    }
    running = false;
}

@Override
public IBinder onBind(Intent arg0) {
    return serviceMessenger.getBinder();
}

public static boolean isRunning(){
    return CrashRecover.running;
}

...

private class ServiceHandler extends Handler{
    public ServiceHandler(Looper looper){
        super(looper);
    }

    @Override
    public void handleMessage(Message message){
        switch(message.what){
            case REGISTER_CLIENT:
                //addActivityToRespawn(null);
                //respawnActivity();
                Log.i("INFO", "Service is registered");
                break;
            case UNREGISTER_CLIENT:
                activityParams = message.getData();
                //respawnActivity();
                if(backgroundThread.isAlive()){
                    stop = true;
                }
                Log.i("INFO", "Service is unregistered");
                break;
            case DESTROY_SERVICE:
                Log.i("INFO", "Service is destroyed");
                break;
            default:
                super.handleMessage(message);
        }
    }
}

}

当我验证服务是否正在运行时，这是我的课程：

public class Main extends Activity {
private Button serviceButton, crashButton;
private Intent serviceIntent;
private ClientMessageHandler clientHandler;

@Override
public void onCreate(Bundle savedInstanceState) {
    ...
    clientHandler = new ClientMessageHandler();
    serviceIntent = new Intent(Main.this, CrashRecover.class);
    startService(serviceIntent);
}

...

@Override
public void onBackPressed(){
    if(CrashRecover.isRunning()){
        Log.i("INFO", "Service is running");
            //Execute some actions
    }
}
...

}

Answer 1

如果您不经常这样做，那么我建议使用“迭代运行服务”方法。不应该在手机上运行那么多服务并且迭代它们只是访问Android保留的一些内部数据结构。应该工作得很好。

检查因类加载器而导致服务失败的状态

1 个答案: