How to add action listener that listens to multiple buttons

0 votes

Below is a simple program that im trying to get a button working in.

What am i doing wrong?

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


public class calc extends JFrame implements ActionListener {



    public static void main(String[] args) {

        JFrame calcFrame = new JFrame();

        calcFrame.setSize(100, 100);
        calcFrame.setVisible(true);

        JButton button1 = new JButton("1");
        button1.addActionListener(this);

        calcFrame.add(button1);
    }

    public void actionPerformed(ActionEvent e) {
        if(e.getSource() == button1)
    }  

}

the action listener is never registered because with the if(e.getSource() == button1) it cant see button1, errors saying cannot find symbol.

Apr 21, 2020 in Java by kartik
• 37,510 points
8,083 views

1 answer to this question.

0 votes

Hii,

modified form of the source based on my comment. Note that GUIs should be constructed & updated on the EDT, though I did not go that far.

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

public class Calc {

    public static void main(String[] args) {

        JFrame calcFrame = new JFrame();

        // usually a good idea.
        calcFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        final JButton button1 = new JButton("1");
        button1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent ae) {
                JOptionPane.showMessageDialog(
                    button1, "..is the loneliest number");
            }
        });

        calcFrame.add(button1);

        // don't do this..
        // calcFrame.setSize(100, 100);

        // important!
        calcFrame.pack();

        calcFrame.setVisible(true);
    }
}
answered Apr 21, 2020 by Niroj
• 82,880 points

Related Questions In Java

0 votes
2 answers

How to test that an array contains a certain value?

public static final String[] VALUES = new ...READ MORE

answered Jul 17, 2018 in Java by Sushmita
• 6,910 points
833 views
0 votes
3 answers

How can I add new elements to an Array in Java

String[] source = new String[] { "a", ...READ MORE

answered Sep 19, 2018 in Java by Sushmita
• 6,910 points
11,605 views
0 votes
2 answers

How can we add leading zeros to the number in Java?

From Java 1.5 you can use the String.format method. ...READ MORE

answered Aug 26, 2019 in Java by Sirajul
• 59,230 points
4,652 views
0 votes
2 answers

How can we add an image to a JPanel?

If you are using JPanels, then are ...READ MORE

answered Sep 20, 2018 in Java by Daisy
• 8,120 points
10,970 views
0 votes
1 answer

What are the prerequisites to learn Hadoop in java perspective?

In my day job, I've just spent ...READ MORE

answered Oct 11, 2018 in Big Data Hadoop by Frankie
• 9,830 points
601 views
0 votes
1 answer

How is inheritance in C++ different than that in Java?

The purpose of inheritance is same for ...READ MORE

answered Feb 6, 2019 in Java by Priyaj
• 58,090 points
733 views
0 votes
1 answer

What is the reason for no ConcurrentHashSet against ConcurrentHashMap?

Hello, There's no built in type for ConcurrentHashSet because you ...READ MORE

answered Apr 8, 2020 in Java by Niroj
• 82,880 points
1,083 views
0 votes
1 answer

How to pass an object from one activity to another on Android?

Hello @kartik, Implement your class with Serializable. Let's ...READ MORE

answered Apr 8, 2020 in Java by Niroj
• 82,880 points
603 views
0 votes
1 answer

How to add tabs to JTabbedPane using WindowBuilder?

Hii, You can just find out by given ...READ MORE

answered Apr 21, 2020 in Java by Niroj
• 82,880 points
940 views
0 votes
1 answer

How to redirect to an external URL from controller action in Spring MVC?

Hello @kartik, You can do it with two ...READ MORE

answered May 22, 2020 in Java by Niroj
• 82,880 points

edited Mar 4, 2022 by Sarfaraz 25,285 views
webinar REGISTER FOR FREE WEBINAR X
REGISTER NOW
webinar_success Thank you for registering Join Edureka Meetup community for 100+ Free Webinars each month JOIN MEETUP GROUP