How to Define Callbacks in Android?

In many cases, you have an interface and pass along an object that implements it. Dialogs for example have the OnClickListener.

Just as a random example:

// The callback interfaceinterface MyCallback {    void callbackCall();}// The class that takes the callbackclass Worker {   MyCallback callback;   void onEvent() {      callback.callbackCall();   }}// Option 1:class Callback implements MyCallback {   void callbackCall() {      // callback code goes here   }}worker.callback = new Callback();// Option 2:worker.callback = new MyCallback() {   void callbackCall() {      // callback code goes here   }};

I probably messed up the syntax in option 2. It's early.

When something happens in my view I fire off an event that my activity is listening for:

// DECLARED IN (CUSTOM) VIEW

    private OnScoreSavedListener onScoreSavedListener;    public interface OnScoreSavedListener {        public void onScoreSaved();    }    // ALLOWS YOU TO SET LISTENER && INVOKE THE OVERIDING METHOD     // FROM WITHIN ACTIVITY    public void setOnScoreSavedListener(OnScoreSavedListener listener) {        onScoreSavedListener = listener;    }

// DECLARED IN ACTIVITY

    MyCustomView slider = (MyCustomView) view.findViewById(R.id.slider)    slider.setOnScoreSavedListener(new OnScoreSavedListener() {        @Override        public void onScoreSaved() {            Log.v("","EVENT FIRED");        }    });

If you want to know more about communication (callbacks) between fragments see here:http://developer.android.com/guide/components/fragments.html#CommunicatingWithActivity

No need to define a new interface when you can use an existing one: android.os.Handler.Callback. Pass an object of type Callback, and invoke callback's handleMessage(Message msg).