load Jpanels from seperate classes

[Kyle Fernandes]

Hello, Im trying to create an interface where I cant change the components of the without have to change frames. For example the main interface would have a empty jPanel in which I would add or remove other jPanels to. The other jPanels say for example one for login would be called from another class and all its components would load on the jpanel on the main interface. after the login button is clicked the login jpanel should be removed from the main and a new one placed in.

Here is some example code..

Login.java

public class Login extends javax.swing.JPanel {

    /** Creates new form Login */
    public Login() {
        initComponents();

    }

    @SuppressWarnings("unchecked")
    private void initComponents() {

        jLabel1 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jLabel3 = new javax.swing.JLabel();
        jPasswordField1 = new javax.swing.JPasswordField();
        jTextField1 = new javax.swing.JTextField();
        jButton1 = new javax.swing.JButton();
        etc.....

    }
    private javax.swing.JButton jButton1;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JPasswordField jPasswordField1;
    private javax.swing.JTextField jTextField1;
}

Main.java

public class Main extends FrameView{

    public Main(SingleFrameApplication app) {
        super(app);
        
        initComponents();
        Login crum = new Login();
        jPanel1.add(crum);
        jPanel1.setVisible(true);
        jPanel1.revalidate();   <------this jPanel is in the main.java and is the one that needs to be replaced or add the login.java jPanel..

any help would be much appreciated thank you..

[Luigi Plinge]

Doesn't the code above work? What happens when you try it?

[Rob Spoor]

Why not use a CardLayout instead?

[Kyle Fernandes]

It doesnt seem to work..I just get a blank area where the panel should be but everything else in the frame seems fine..Im not sure if I should setVisible() somewhere..
Im not familiar with card layout..:/Im using netbeans..drag and drop...

[Kyle Fernandes]

I tried to change the add(component) part to jPanel1.add(crum, BorderLayout.CENTER);
now Im getting this new error, Im not sure if its related..

Exception "java.lang.ClassNotFoundException: org.openide.loaders.DataObject"while constructing DataFlavor for: application/x-java-openide-dataobjectdnd; mask=1; class=org.openide.loaders.DataObject

[Luigi Plinge]

I don't know about the exception - sometimes class loading errors might be because you've spelt the class name wrong.

What layout manager are you using with your panel? JPanels have a FlowLayout by default, so trying to add something with BorderLayout parameters might cause problems. Also your code looks like it's from NetBeans, which uses something called a GroupLayout unless you tell it to use something else.

[Luigi Plinge]

I did an experiment and it seems you need to both validate() and repaint() the container when you add a new panel to it.

Ignore all (generated) code up to line 53

package experiments;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.Timer;

public class PanelSwapDemoFrame extends javax.swing.JFrame {

    /** Creates new form PanelSwapDemoFrame */
    public PanelSwapDemoFrame() {
        initComponents();
    }

    /** This method is called from within the constructor to initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">
    private void initComponents() {

        panel = new javax.swing.JPanel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        panel.setBackground(new java.awt.Color(255, 255, 204));
        panel.setBorder(javax.swing.BorderFactory.createLineBorder(new java.awt.Color(0, 0, 0), 2));
        panel.setLayout(new java.awt.BorderLayout());

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(67, 67, 67)
                .addComponent(panel, javax.swing.GroupLayout.PREFERRED_SIZE, 259, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(74, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(56, 56, 56)
                .addComponent(panel, javax.swing.GroupLayout.PREFERRED_SIZE, 183, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(61, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {

            public void run() {
                final PanelSwapDemoFrame f = new PanelSwapDemoFrame();

                f.setVisible(true);

                final JPanel p1 = new JPanel();
                final JPanel p2 = new JPanel();

                p1.add(new JLabel("panel 1"));
                p2.add(new JLabel("JPanel number 2"));

                f.addPanel(p1);

                new Timer(1000, new ActionListener() {

                    private JPanel current = p1;

                    public void actionPerformed(ActionEvent e) {
                        if (current == p1) {
                            f.swapPanels(p1, p2);
                            current = p2;
                        } else {
                            f.swapPanels(p2, p1);
                            current = p1;
                        }
                    }
                }).start();
            }
        });
    }

    public void addPanel(JPanel p) {
        panel.add(p);
    }

    public void swapPanels(JPanel a, JPanel b) {
        panel.remove(a);
        panel.add(b);
        panel.validate();
        panel.repaint();
    }
    // Variables declaration - do not modify
    private javax.swing.JPanel panel;
    // End of variables declaration
}

[Rob Spoor]

You do if you add / remove components after the parent has already been made visible.