Android - OnClick Listener in a separate class

Question

Is it possible to make a secondary class to hold the OnClick Listener? Meaning not being created in the Activity class?

I just find that putting OnClick listeners in the main activity class is just messy and I would rather have them in separate classes. Thanks

Answer 1

Sure, that's possible. Just create a class that implements View.OnClickListener and set that as listener to the View. For example:

public class ExternalOnClickListener implements View.OnClickListener {

    public ExternalOnClickListener(...) {
        // keep references for your onClick logic 
    }

    @Override public void onClick(View v) {
        // TODO: add code here
    }

}

And then set an instance of above class as listener:

view.setOnClickListener(new ExternalOnClickListener(...));

The parameterized constructor is optional, but it's very likely you'll need to pass something through to actually make your onClick(...) logic work on.

Implementing a class anonymously is generally easier to work with though. Just a thought.

Answer 2

Instead of putting the onCLicklistener in a separate class, why dont you try to define onClickListener outside onCreate()??

For e.g: like this

onCreate()

yourViewName.setOnClicklistener(listener):

Outside onCreate()

private OnClickListener listener    =   new OnClickListener() {
        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

        }
    };

Answer 3

Yes you can. However, making the listener an inner class has one advantage - it can access the fields and variables of your activity class directly. If you make it a separate class, and your listener actually need to access 5 views, your listener constructor might look like this:

MyListener listener = new MyListener(context, button, textView1, textView2, ratingBar, imageView);

Which is kinda bulky too. If your listener is simple, go ahead and make it a separate class. Otherwise, its up to you for readability.