JFrame/JPanel refreshing and text fields

Question

I'm trying to switch between displaying different JPanels in BorderLayout.CENTER in a JFrame. The JPanels each contain a JTextField and a JTextPane. Calling revalidate() and repaint() on the JFrame, I get a very strange result: the first time I switch to secondPanel by clicking secondButton , everything works as expected. Then when I try to switch back using firstButton , nothing happens. It only switches back when I click secondButton again, and after that it works just as expected, except in reverse: clicking firstButton displays secondPanel and clicking secondButton displays firstPanel .

Calling revalidate() and repaint() on the JPanel to be displayed instead, everything works fine, until I click either text area. With every click, it's like part of the text "falls off" like it was just a facade, revealing the text of the corresponding area of the other JPanel underneath. If I type something, the text changes instantly to that of the other JPanel, and whatever I typed is added to it even after switching JPanels. It's really weird and hard to describe properly, so just see for yourselves.

I have three questions: 1. what the hell, 2. why the hell, and 3. how do I fix it?

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

public class MyFrame extends JFrame {

    class MyActionListener implements ActionListener {
        JPanel panel;
        MyActionListener(JPanel _panel) {
            panel = _panel;
        }

        @Override
        public void actionPerformed(ActionEvent ae) {
            MyFrame.this.add(panel, BorderLayout.CENTER);
            //MyFrame.this.revalidate();
            //MyFrame.this.repaint();
            panel.revalidate();
            panel.repaint();
        }
    }

    JPanel buttonPanel = new JPanel();

    JButton firstButton = new JButton("first");
    JPanel firstPanel = new JPanel();
    JTextPane firstPane = new JTextPane();
    JTextField firstField = new JTextField("first field");

    JButton secondButton = new JButton("second");
    JPanel secondPanel = new JPanel();
    JTextPane secondPane = new JTextPane();
    JTextField secondField = new JTextField("second field");

    MyFrame() {
        firstPane.setText("first pane");
        firstPanel.setLayout(new BorderLayout());
        firstPanel.add(firstPane, BorderLayout.CENTER);
        firstPanel.add(firstField, BorderLayout.SOUTH);
        firstButton.addActionListener(new MyActionListener(firstPanel));

        secondPane.setText("second pane");
        secondPanel.setLayout(new BorderLayout());
        secondPanel.add(secondPane, BorderLayout.CENTER);
        secondPanel.add(secondField, BorderLayout.SOUTH);
        secondButton.addActionListener(new MyActionListener(secondPanel));

        buttonPanel.setLayout(new GridLayout(0,1));
        buttonPanel.add(firstButton);
        buttonPanel.add(secondButton);

        add(buttonPanel, BorderLayout.WEST);
        add(firstPanel, BorderLayout.CENTER);

        setSize(new Dimension(300,300));
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);
    }

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

Answer 1

how do I fix it?

Use a CardLayout . See the section from the Swing tutorial on How to Use CardLayout for more information and examples.