扩展ActionEvent吗？ 没有自定义侦听器的自定义事件？

Question

I've 2 Objects I'm concerned with at the moment: a controller and a class creating an event.

I've got it all working with an ActionListener variable in the source class, set by an anonymous ActionListener object and method from the controller.

But I need access to data from the source class back in the controller. I'm capable of extending EventListener and using a custom EventObject, but that seems a bit overkill for one bit of data.

Is there an easy way to just extend ActionEvent and create an extra variable that I can access in the Listener's actionPerformed() method? ActionEvent's constructor is just confusing me.

public class NotesEvent extends ActionEvent{
    public NotesEvent(Object source, int id, String command){
        super(source, id, command);
    }
}

I don't know what to pass for the 'identifier' when instantiating the event.

Maybe I've missed something simple - I've only ever really learned to do this the long way round with custom classes.

Any help would be appreciated

Answer 1

I was making the mistake of not downcasting the custom event in the controller, so I thought that ActionListener wouldn't play nice with a custom event - but it does seem to (which is what I initially thought)

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;

public class Target {
    ActionListener listener;
    int data = 1;

    public Target(){
        JButton b = new JButton("Press Me");

        b.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e){
                CustomEvent ce = new CustomEvent(data, Target.this, 0, "Command");
                if(listener != null) listener.actionPerformed(ce);
            }
        });
    }

    public void setListener(ActionListener listener){
        listener = listener;
    }  
}

class CustomEvent extends ActionEvent{
    int data;
    CustomEvent(int data, Object source, int id, String command){
        super(source, id, command);
        this.data = data;
    }

    public int getData(){
        return data;
    }
}

The controller class:

import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener;
import javax.swing.JButton;

public class Controller {
    Target t = new Target();

    public static void main(String[] args){
        Controller c = new Controller();
    }

    public Controller(){
        t.setListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e) {
               //here was my problem 
               System.out.println(((CustomEvent)e).getID());
            }
        });
    }
}

I'm still not entirely sure about the data I should be passing to the ActionEvent constructor though.

Hope the above makes clear what I was trying to achieve (I know it's not actually complete in terms of the UI appearing.)