How can I replace one of two JPanels with another JPanel in Java?

Question

I designed an interface for the welcome screen with one JFrame included two JPanels (JPanel1 on right and JPanel2 on left). The buttons on the left is to switch the Panels in JPanel1. I want to press on a button to replace JPanel1 content with another JPanel but I don`t know how. Please help.

Answer 1

Here is a very simple example of something that should approximate your description. On the left, we have a hug button to toggle the content of the right panel. On the right, you have a panel with a given border and a label. When you press the button, the content on the right is swapped with the other panel.

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class TestCardLayout2 {

    protected void initUI() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JPanel leftPanel = new JPanel(new BorderLayout());
        JLabel label = new JLabel("Left panel");
        leftPanel.add(label, BorderLayout.NORTH);
        JButton button = new JButton("Toggle right panel");
        leftPanel.add(button);
        frame.add(leftPanel, BorderLayout.WEST);

        final CardLayout cardLayout = new CardLayout();
        final JPanel rightPanel = new JPanel(cardLayout);
        rightPanel.setPreferredSize(new Dimension(200, 500));

        JPanel rightPanel1 = new JPanel(new FlowLayout(FlowLayout.LEFT));
        rightPanel1.setBorder(BorderFactory.createLineBorder(Color.RED));
        JPanel rightPanel2 = new JPanel(new FlowLayout(FlowLayout.RIGHT));
        rightPanel2.setBorder(BorderFactory.createLineBorder(Color.BLUE));
        JLabel label1 = new JLabel("Right panel 1 with a red border");
        JLabel label2 = new JLabel("Right panel 2 with a blue borer");
        rightPanel1.add(label1);
        rightPanel2.add(label2);

        rightPanel.add(rightPanel1, "panel1");
        rightPanel.add(rightPanel2, "panel2");
        frame.add(rightPanel, BorderLayout.EAST);

        button.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                cardLayout.next(rightPanel);
            }
        });
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new TestCardLayout2().initUI();
            }
        });
    }

}

Answer 2

An alternative to CardLayout would be JRootPane and its JRootPane.setContentPane() method. Here's an example:

final JPanel panel1 = ...;
final JPanel panel2 = ...;
boolean showingPanel1 = true;
final JRootPane rootPane = new JRootPane();
rootPane.setContentPane(panel1);
JButton switchButton = new JButton("Switch");
switchButton.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent evt) {
        if (showingPanel1) {
            rootPane.setContentPane(panel2);
        } else {
            rootPane.setContentPane(panel1);
        }
        showingPanel = !showingPanel;
    }
});

Add the rootPane and switchButton components to your window, and then clicking switchButton will switch out the panels.

Here's a tutorial. You should mostly be concerned with JRootPane.setContentPane, the other stuff in the tutorial isn't relevant.

Answer 3

The best answer I found is that I will create one JFrame only and gonna make one big JPanel include two JPanels (JPanelLeft include the buttons and JPanelRight include what the button do) then I will copy the main JPanel for each JButton. When I press on any button I will do (JFrame.getContentPane.removeAll) to remove the old JPanel then (JFrame.getContentPane.Add(NewJPanel).

This works for me and keep my design as I Want. Thanks for every body.