CODEWITHSUNDEEP
javaswing
Philana
Philana

Reputation: 25

Why is my second button for a GUI not working?

I'm trying to get my second button to subtract the starting number, but I keep getting errors where ButtonListener1 is located (line 23 and 47) and I am unable to run my code.
I don't understand why it isn't working.
Please tel me if I'm supposed to add something to the button and operation in the private classes or the main class. 

package addsubtract;

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

public class SubtractAdd extends JApplet {

    private int APPLET_WIDTH = 300, APPLET_HEIGHT = 35;
    private int num;
    private JLabel label;
    private JButton add;
    private JButton subtract;

    public void init ()
    {
        num = 50;

        add = new JButton ("Add");
        add.addActionListener (new ButtonListener());
        subtract = new JButton ("Subtract");
        subtract.addActionListener ((ActionListener) new ButtonListener1());

        label = new JLabel("Number: " + Integer.toString (num));

        Container cp = getContentPane();
        cp.setBackground (Color.PINK);
        cp.setLayout (new FlowLayout());
        cp.add(add);
        cp.add(subtract);
        cp.add(label);

        setSize (APPLET_WIDTH, APPLET_HEIGHT);

    }

    private class ButtonListener implements ActionListener
    {
        public void actionPerformed (ActionEvent event)
        {
            num++;
            label.setText("Number: " + Integer.toString(num));

        }

    private class ButtonListener1 implements ActionListener
    {   
        public void actionPerfomred (ActionEvent event)    
        {
            num--;
            label.setText("Number: " + Integer.toString(num));

        }
    }  
    }
}

Upvotes: 1

Views: 67

Answers (1)

OneCricketeer
OneCricketeer

Reputation: 191728

I don't think you need the private classes. Plus, I believe they are causing you scoping issues (can't access num from within them).

Instead, you can make anonymous classes

add = new JButton ("Add");
add.addActionListener (new ActionListener() {
    @Override
    public void actionPerformed (ActionEvent event) {
        label.setText("Number: " + (++num));
    }
});
subtract = new JButton ("Subtract");
subtract.addActionListener (new ActionListener() {
    @Override
    public void actionPerformed (ActionEvent event) {
        label.setText("Number: " + (--num));
    }
});

Or have the class implement the interface 

public class SubtractAdd extends JApplet implements ActionListener {

    public void init() {

        add = new JButton ("Add");
        add.addActionListener (this);
        subtract = new JButton ("Subtract");
        subtract.addActionListener(this);

    }

    @Override
    public void actionPerformed (ActionEvent event) {
        Object source = event.getSource();
        if (source == add) {
            label.setText("Number: " + (++num));
        } else if (source == subtract) {
            label.setText("Number: " + (--num));
        }
    });

Upvotes: 3

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