Print Page - Android: Events

When trying to figure out how to send events from Activities to Mediators, I first created interface InteractionListener for the Mediator to implement:

package com.britton.apps.puremvcboilerplate.view;

import com.britton.apps.puremvcboilerplate.view.event.InteractionEvent;

public interface InteractionListener {
	public void interactionReceived(InteractionEvent event);
	public void configureListeners(InteractionListener m);
}

Implementation in Mediator:

@Override
public void onRegister() {
	super.onRegister();
	configureListeners(this);
}

@Override
public void configureListeners(InteractionListener m) {
	this.getApplication().addListener(m);
}

@Override
public void interactionReceived(InteractionEvent event) {
	Log.d(TAG, "Event Received");
}

In my experimental app, Activity is subclassed as InteractionActivity (which could also be an abstract class):

package com.britton.apps.puremvcboilerplate.view;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;

public class InteractionEmitterActivity extends Activity {
	public List listeners;
	
	public InteractionEmitterActivity() {
		listeners = new ArrayList();
	}
	
	public synchronized void addListener(InteractionListener il) {
        listeners.add(il);
    }

    public synchronized void removeListener(InteractionListener il) {
        listeners.remove(il);
    }
}

And in ApplicationActivity, the subclass, where there's a Button ready to trigger this miraculous handler:

private void initDisplay() {
	btn = (Button) findViewById(R.id.button1);
	btn.setOnClickListener(new View.OnClickListener() {
		
		public void onClick(View v) {
			InteractionEvent ie = new InteractionEvent(this);
			Iterator it = listeners.iterator();
			
			while (it.hasNext()) {
				InteractionListener il = (InteractionListener) it.next();
				il.interactionReceived(ie);
			}
		}
	});
}

So now, any Activity that extends InteractionEmitterActivity can, by contract, send InteractionEvents to the Mediator actor.

Here's the InteractionEvent:

package com.britton.apps.puremvcboilerplate.view.event;

import java.util.EventObject;

public class InteractionEvent extends EventObject {
	
	public InteractionEvent(Object source) {
		super(source);
	}
}

I realize this is very Flex-like; in fact, I kept thinking about Signals when I wrote it! I've had success with them. Maybe that's another route.

Mike

PureMVC Architects Lounge

PureMVC Manifold => MultiCore Version => Topic started by: mikebritton on April 05, 2011, 01:02:38