Addactionlistener doesnot take parameter

Question

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class Concentration extends JFrame implements ActionListener {

    private JButton buttons[][]=new JButton[4][4];
    int i,j,n;      

    public Concentration() {            
        super ("Concentration");    
        JFrame frame=new JFrame();
        setSize(1000,1000);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel panel=new JPanel(new GridLayout(4,4));
        panel.setSize(400, 400);            
        for( i=0; i<buttons.length; i++){
            for (j=0; j<buttons[i].length;j++){ 
                n=i*buttons.length+buttons[i].length;
                buttons[i][j]=new JButton();                    
                panel.add(buttons[i][j]);
                buttons[i][j].addActionListener(this);
            }
        }
        add(panel);
        pack();
        setVisible(true);       
    }

    public void actionPerformed(ActionEvent e) {            
        buttons[i][j].setIcon(new ImageIcon(
                 getClass().getResource("/images/2.jpg")));
    }

    public static void main(String args[]){
        new Concentration();
    }    
}

This is my code. I am making memory game. I want to make that, each time clicked a button, that button shows image but

 buttons[i][j].addActionListener(this);

in that, methot can not take i and j and doesnot show any image.

But for example when i do

 buttons[2][2].addActionListener(this);

it shows only in 2x2 . image. What can i do to solve that?

score 3 · Accepted Answer · answered Sep 23 '13 at 12:04

Possible solutions:

Inside the ActionListener, iterate through the button array to see which JButton in the array matches the button that was pressed, obtained by calling e.getSource()
Give your JButtons actionCommand Strings that correspond to i and j
Create a separate ActionListener implementing class that has i and j fields that can be set via a constructor, and give each button a unique ActionListener with i and j set.

dic19 · Answer 2 · 2013-09-23T12:30:28.367

2

Try this code:

public void actionPerformed(ActionEvent e) {
    if(e.getSource() instanceof JButton){
        JButton pressedButton = (JButton) e.getSource();
        if(pressedButton.getIcon() == null){
            pressedButton.setIcon(new ImageIcon(getClass().getResource("/images/2.jpg")));
        } else {
            pressedButton.setIcon(null);
        }
    }
}

Direct form EventObject javadoc:

public Object getSource()

The object on which the Event initially occurred.

Returns: The object on which the Event initially occurred.

This means there's no need to know the array indexes of pressed button as it could be known through getSource() method.

edited Sep 23 '13 at 12:30

answered Sep 23 '13 at 12:07

dic19

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1

@nIcEcOw I have +1 (think is yours, thank you) but another -1 that I'd like to know why. – dic19 Sep 23 '13 at 12:49
1

You've got one 1+ from me. It's good to show the getSource() method in action with explanation. Thanks. – Hovercraft Full Of Eels Sep 23 '13 at 17:05
Oh, I see then. Thanks guys! :) @nIcEcOw yes, I'll keep smiling :-) – dic19 Sep 23 '13 at 18:12

Addactionlistener doesnot take parameter

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