One Service Multiple Activities in Android

Question

I have a service and 3 activities. The service is started in the first activity. Now when I move to the second activity and pressing on some button, I want to send a data to the service.

so in the second activity, inside the click listener I did the following:

 Intent service = new Intent(MyService.class.getName()); 
 service.putExtra("dataToSend",data.toString());
 startService(service);

but the method onStartCommand inside the service, doesn't get called..

Also, I want to create this service to work with multiple activities. I mean each activity will be able to send a data to this service and get a data from it.

Answer 1

Hi you need to bind your running service to activity you need to access it again. Following code snippets you can used as a reference

@Override
protected void onStart() {
    super.onStart();
    Intent mIntent = new Intent(this, MyService.class);
    bindService(mIntent, mConnection, BIND_AUTO_CREATE);
};

ServiceConnection mConnection = new ServiceConnection() {

    public void onServiceDisconnected(ComponentName name) {
        mBounded = false;
        myService= null;
    }

    public void onServiceConnected(ComponentName name, IBinder service) {
        // Toast.makeText(context, "Service is connected", 1000).show();

        mBounded = true;
        LocalBinder mLocalBinder = (LocalBinder) service;
        myService= mLocalBinder.getServerInstance();

      //now you are able to access any method in service class 
    }
};

Answer 2

QUESTION
I want to create this service to work with multiple activities. I mean each activity will be able to send a data to this service and get a data from it.

You don't have to do nothing with your Service. Services remain the same if they are not destroyed, that means all your Activities will be able to access to it's data.

PROBLEM

but the method onStartCommand inside the service, doesn't get called..

WHY
As long as your service has started, the onStartCommand is not called each time:

onStartCommand

Called by the system every time a client explicitly starts the service by calling startService(Intent), providing the arguments it supplied and a unique integer token representing the start request.

startService

Request that a given application service be started.

SOLUTION
call the events you need in onRebind method:

Called when new clients have connected to the service, after it had previously been notified that all had disconnected in its onUnbind(Intent). This will only be called if the implementation of onUnbind(Intent) was overridden to return true.