I have an Activity that starts a service which isn't local. Sometimes I check if is alive to perform actions.
My attempt at the moment was to use a static boolean variable. Reading some posts on SO I found out this not works because each process has it's own classloader.
Iterating over all running services is expensive to do a simple task like this.
Other solutions points out to use AIDL. In a very near future in my service, I'll store a WeakReference for the current running activity to execute it again in case of crash. Assuming for now I just want to check the service' state, is this an expensive solution too?
P.S.: I know it's an ugly solution to not handle exception properly. It's just a try.
EDIT: To clarify what I'm doing I post some code. This is the Service classs:
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);
}
}
}
}
And this is my class when I verify if service is running:
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
}
}
...
}
