Java - Loop to create Action Listeners

Question

Is there any way to set up a loop to create multiple very similar action-listeners? For purely academic purposes, I created a card game, each card is a button, when you click on the card, it should turn face-up. The game works fine, but each action listener is set up individually. Below is my attempt at a loop.

String string1;
String string2;

// called by the constructor
public void setupActionListener() {
    int loopVar = 0;

    while (loopVar <= 16) {
        string1 = "card"+loopVar;
        string2 = "c"+loopVar;

             string1 string2 = new string1();           //A
             // -> card0 c0 = new card0();

             card[loopVar].addActionListener(string2);  //B
             // -> card[0].addActionListener(c0);

    loopVar = loopVar + 1;
}


// the action listener

public class card0 implements ActionListener {          //C
    public void actionPerformed(ActionEvent c0) {       //D
        // perform actions
    }  
}

EDIT: First, I never thought "string1 string2 = new string1();" would work, I was just going for a general idea.

Judging from the comments, it seems I have asked this question in a confusing way, all I meant is I have this in the constructor:

card0 c0 = new card0();
card[0].addActionListener(c0); 
card1 c1 = new card1();
card[1].addActionListener(c1); 
card2 c2 = new card2();
card[2].addActionListener(c2);
card3 c3 = new card3();
card[3].addActionListener(c3);
card4 c4 = new card4();
...     
card15 c15 = new card15();
card[15].addActionListener(c15);

And later this:

public class card0 implements ActionListener {
    public void actionPerformed(ActionEvent c0) {
        move(0);
    }  
}

public class card1 implements ActionListener {
    public void actionPerformed(ActionEvent c1) {
        move(1);
    }  
}

public class card15 implements ActionListener {
    public void actionPerformed(ActionEvent c2) {
        move(2);
    }  
}
...
public class card15 implements ActionListener {
    public void actionPerformed(ActionEvent c15) {
        move(15);
    }  
}

And I wanted to know if it was possible to put all this into a loop. It seems the answer is no, but I was just asking.

What do you think string1 string2 = new string1(); should do? — BitNinja
– BitNinja, Commented Aug 19, 2014 at 23:04
I would rather create one instance of the listener and have its logic find which button raised the event. — SJuan76
– SJuan76, Commented Aug 19, 2014 at 23:04
You should start with some java tutorial because judging from this: string1 string2 = new string1() there's a lot to explain here. Try finding some tutorial like: docs.oracle.com/javase/tutorial or learnjavaonline.org — Michał Schielmann
– Michał Schielmann, Commented Aug 19, 2014 at 23:08
Start by taking a look at How to Write an Action Listeners. I don't know what card is, but most components that support the ActionListener API require an instance of an ActionListener when registering... — MadProgrammer
– MadProgrammer, Commented Aug 20, 2014 at 0:04

Michał Schielmann · Accepted Answer · 2014-08-19 23:26:22Z

3

The code you presented is not very rich so I'm not sure if I understand you correctly, but maybe this pseudo-code would help you.

public class Card extends SomeComponent{
    public void turn() {
        //doStuff
    }
}

public class CardGame {

    private SomeComponent[] cards;
    public void prepareGame() {
        CardListener listener = new CardListener();
        for (int i=0; i<=16; i++) {
            cards[i] = new Card();
            cards[i].addActionListener(listener);
        }
    }
}

public class CardListener implements ActionListener {

    public void actionPerformed(ActionEvent e) {
        ((Card) e.getSource()).turn();
    }

}

You can use adding MouseListener or KeyListener instead of ActionListener which doesn't give you much information about what has happened.

answered Aug 19, 2014 at 23:26

Michał Schielmann

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