Question

It’s my first question on SO, I hope this question won’t be bad.

I have a service, it starts working when user launchs an app and works until user will kill it via task killer or turn off his device.

This service has a background thread which does some work with data. I need to bind activities (from activities, not by service) and sometimes (1-2 times per 30 seconds) send data to binded activities.

Structure of my service:

public class myserv extends Service {
  public static boolean started=false;
  public class workwithdata extends Thread {
    @Override
    public synchronized void start() {
      super.start();
      //.. Not important.
    }
    @Override
    public void run() {
      if (running) return;
      while (true) {
        if(condition) mythread.sleep(30000);
        else {
          Object data = recieveMyData();
          if (!data.isEmpty()) {
            //.. Some work with recieved data, not important.
            sendDataToBindedActivities(data); //This is what I need.
          }
          mythread.sleep(10000);
        }
      }
    }
  }
  @Override
  public void onCreate() {
    super.onCreate();
    this.started=true;
    mythread = new workwithdata();
    mythread.start();
  }
}

Well, I found one question but my problem has a little differences: I don’t need to send any data to the service, I need just send some data to all binded activities (which service doesn’t know at all).

Structure for which I’m looking for:

public class myact extends Activity {
  @Override
  public void onCreate(Bundle bun) {
    super.onCreate(bun);
    if(!myserv.started) {
      Intent service = new Intent(getApplicationContext(), myserv.class);
      getApplicationContext().startService(service);
    }
    bindToService(this);
  }
  @Override
  public void onRecievedData(Object data) {
    //work with recieved data from service "myserv".
  }
}

I also tried to find some solutions in android documentation but I didn’t find what I need.

So, main question is: is it possible to work with communications from service to activities?. If no: What should I use for this purpose? If yes, just, sorry, can I ask for some code or class names, because I tried to find and didn’t…

Thank you.

Answer 1

You need to use a RemoteCallbackList

When your clients bind to the service, you will need to register them using RemoteCallbackList.register().

When you want to send data to the bound clients, you do something like this:

int count = callbackList.beginBroadcast();
for (int i = 0; i < count; i++) {
    try {
        IMyServiceCallback client = callbackList.getBroadcastItem(i);
        client.onRecievedData(theData); // Here you callback the bound client's method
                                  //  onRecievedData() and pass "theData" back
    } catch (RemoteException e) {
        // We can safely ignore this exception. The RemoteCallbackList will take care
        //  of removing the dead object for us.
    } catch (Exception e) {
        // Not much we can do here except log it
        Log.e("while calling back remote client", e);
    }
}
callbackList.finishBroadcast();

An example can be found here It is kinda complicated, but maybe you don’t need everything this offers. In any case, have a look.