我有一个活动启动了一个非本地服务。有时我会检查是否还活着以执行操作。
我目前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,因为每个进程都有自己的类加载器。
循环访问所有正在运行的服务对于执行这样的简单任务是昂贵的。
其他解决方案指出使用 AIDL。在不久的将来,在我的服务中,我将为当前正在运行的活动存储一个弱引用,以便在崩溃时再次执行它。假设现在我只想检查服务的状态,这也是一个昂贵的解决方案吗?
PS:我知道不正确处理异常是一个丑陋的解决方案。这只是一个尝试。
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);
}
}
}
}
这是我验证服务是否正在运行时的类:
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
}
}
...
}
如果您不经常这样做,那么我建议您使用"迭代正在运行的服务"方法。手机上不应该运行那么多服务,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。