How to Define Callbacks in Android?

Question

During the most recent Google IO, there was a presentation about implementing restful client applications. Unfortunately, it was only a high level discussion with no source

Answer 1

to clarify a bit on dragon's answer (since it took me a while to figure out what to do with Handler.Callback):

Handler can be used to execute callbacks in the current or another thread, by passing it Messages. the Message holds data to be used from the callback. a Handler.Callback can be passed to the constructor of Handler in order to avoid extending Handler directly. thus, to execute some code via callback from the current thread:

Message message = new Message();


Callback callback = new Callback() {
    public boolean handleMessage(Message msg) {
        
    }
};

Handler handler = new Handler(callback);
handler.sendMessage(message);

EDIT: just realized there's a better way to get the same result (minus control of exactly when to execute the callback):

post(new Runnable() {
    @Override
    public void run() {
        
    }
});