Java Swing How to - Change JPanel background with JButton

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Question

We would like to know how to change JPanel background with JButton.

Answer

/* ww  w .  j a v a 2  s. c o m*/
import java.awt.Color;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class Main extends JPanel implements ActionListener {

    private JButton yellowButton = new JButton("Yellow");

    private JButton blueButton = new JButton("Blue");

    private JButton redButton = new JButton("Red");

    public Main() {
        add(yellowButton);
        add(blueButton);
        add(redButton);

        yellowButton.addActionListener(this);
        blueButton.addActionListener(this);
        redButton.addActionListener(this);
    }

    public void actionPerformed(ActionEvent evt) {
        Object source = evt.getSource();
        Color color = getBackground();
        if (source == yellowButton)
            color = Color.yellow;
        else if (source == blueButton)
            color = Color.blue;
        else if (source == redButton)
            color = Color.red;
        setBackground(color);
        repaint();
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setSize(300, 200);
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });

        Container contentPane = frame.getContentPane();
        contentPane.add(new Main());

        frame.setVisible(true);
    }
}

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