CODEWITHSUNDEEP
javaswing
Jim
Jim

Reputation: 81

Erase Swing Content Pane/Panel & display a new panel

I have created an applet where when you press the button "Forgot Pass" I erase the current JPanel on the applet & create a new JPanel that displays the JComponents related to Retrieving/Forgetting a password.

I can successfully clear the JPanel using .removeAll(); BUT after I create all my new JComponents & add them to the content pane (main JPanel) the applet just goes gray & doesn't show the new JPanel & components UNLESS I resize the applet, then it repaints & works.

I have tried putting .invalidate() after I have created all the new JComponents but that still doesn't refresh the applet?

How can I make my JPanel appear after I clear it with .removeAll() & add different JComponents to it?

Code: 

public class App extends JApplet
{
    JPanel mainPanel; 

    public void init()
    {
        SwingUtilities.invokeAndWait( new Runnable() {
            public void run()
            {
                showLoginPanel(); // this shows fine on loading
            }
        });

    }

    public void showForgotPassPanel()
    {
        mainPanel.removeAll();

        mainPanel = (JPanel) getContentPane();
        Box hBox  = Box.createHorizontalBox();
        Box vBox  = Box.createVerticalBox();
        mainPanel.setLayout( new BorderLayout() ); 

        ... create components

        ... add components to mainPanel

        mainPanel.invalidate(); // doesn't make new layout visible, not unless I resize the applet
    }
}

Upvotes: 5

Views: 12033

Answers (3)

Gio
Gio

Reputation: 1

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

import static javax.swing.JFrame.EXIT_ON_CLOSE;

import java.awt.HeadlessException;

public class PruebaVentana extends JFrame {
    JButton b1, b2;
    JPanel panel1 = new JPanel();
    JPanel panel2 = new JPanel();
    JPanel contenedor = new JPanel();

    public PruebaVentana() throws HeadlessException, InterruptedException {
        super("Abriendo nuevo JPanel por medio de un botón");
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        this.setBounds(50, 50, 500, 300);

        iniciarPanel();
    }// fin de constructor PruebaVentana

    public void iniciarPanel() {
        this.getContentPane().add(contenedor);
        contenedor.setLayout(null);
        contenedor.add(this.panel1);
        contenedor.add(this.panel2);
        panel2.setBackground(new Color(0, 10, 150));
        panel1.setBackground(new Color(150, 0, 0));

        panel1.setBounds(0, 0, 500, 230);
        panel2.setBounds(0, 0, 500, 230);
        panel1.setLayout(null);
        panel2.setLayout(null);
        panel2.setVisible(false);

        b1 = new JButton("Abre Panel 2");
        b2 = new JButton("Abre Panel 1");

        b1.setBounds(10, 10, 150, 30);
        b1.setForeground(new Color(200, 100, 50));
        b2.setBounds(170, 10, 150, 30);
        b2.setForeground(new Color(50, 100, 200));

        panel1.add(b1);
        panel2.add(b2);

        b1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                panel2.setVisible(true);
                panel1.setVisible(false);
            }// fin de actionPerformed
        });// fin de actionListener

        b2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                panel1.setVisible(true);
                panel2.setVisible(false);
            }// fin de actionPerformed
        });// fin de actionListener

    }// fin de iniciarPanel

    public static void main(String[] args) throws HeadlessException, InterruptedException {
        PruebaVentana v = new PruebaVentana();
        v.setVisible(true);

    }// fin de método main

}// fin de clase PruebaVentana

Upvotes: 0

Hovercraft Full Of Eels
Hovercraft Full Of Eels

Reputation: 285405

Another "clean" option is to swap views with a CardLayout. It does all the dirty work for you behind the scenes.

Upvotes: 0

POSIX_ME_HARDER
POSIX_ME_HARDER

Reputation: 762

Use mainPanel.revalidate(); and/or mainPanel.repaint(); methods.

Upvotes: 5

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