Communication between Activity and Service

user_1338333 0
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I am trying to make my own MusicPlayer for android. Where i came to a problem is running some things in background. Main activity manages GUI and up to now all the songs are playing. I wanted to separate GUI and music playing classes. I want to put music managing part in Service and leave other things as they are now.

My problem is that i can't organize communication between Activity and Service as lot of communication is happening between them including moving objects in both directions. I tried many techniques that I searched here on Stack Overflow but every time I had problems. I need Service to be able to send objects to Activity and vice versa. When I add widget i also want it to be able to communicate with Service.

Any tips are appreciated, if you need source code place comment bellow but now in this transition it became chaotic.

Is there any more advanced tutorial on this than calling one method that returns random number from service? :P

EDIT: Possible solution is to use RoboGuice library and move objects with injection

message-passing android-service android-activity android
8 Answers

Most easy and efficient way will be using EventBus from GreenRobot.

Use simple 3 steps:

1 Define events

public static class MessageEvent { /* Additional fields if needed */ }

2 Prepare subscribers: Declare and annotate your subscribing method, optionally specify a thread mode:

@Subscribe(threadMode = ThreadMode.MAIN)  
public void onMessageEvent(MessageEvent event) {/* Do something */};

Register and unregister your subscriber. For example on Android, activities and fragments should usually register according to their life cycle:

@Override
 public void onStart() {
     super.onStart();
     EventBus.getDefault().register(this);
 }

 @Override
 public void onStop() {
     super.onStop();
     EventBus.getDefault().unregister(this);
 }

3 Post events:

EventBus.getDefault().post(new MessageEvent());
user_68915630

Very easy yet powerful way is to use EventBus you can add it to your gradle build and enjoy the easy publisher/subscriber pattern .

user_8485790
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