How to add a JInternalFrame to JFrame?

Question

I have my JFrame, and I want to attach to a button an ActionListener that triggers the JInternalFrame.

I do:

private void aboutMenuItemActionPerformed(java.awt.event.ActionEvent evt) {
    AboutFrame about = new AboutFrame(); //jInternalFrame
    this.add(about);        
}

But it doesn't bring it to front. What did I miss?

Answer 1

You probable want to use a JDesktopPane, then set the content pane of your frame to the desktop pane

    JDesktopPane desktop = new JDesktopPane(); //a specialized layered pane
    createFrame(); //create first "window"
    setContentPane(desktop);

Then you can do something like this

private void aboutMenuItemActionPerformed(java.awt.event.ActionEvent evt)
{                                              
    AboutFrame about = new AboutFrame();           <--- JInternalFrame
    about.setVisible(true); //necessary as of 1.3  <--- set it visible
    desktop.add(about);                            <--- add to desktop
    try {
        about.setSelected(true);                   <--- set it selected
    } catch (java.beans.PropertyVetoException e) {}        

}

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See How to Us Internal Frames

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UDATE

Run this example, I made on NetBeans GUI Builder also. It works fine, without the behavior yout're talking about.

public class NewJFrame extends javax.swing.JFrame {
    public NewJFrame() {
        initComponents();
    }

    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jDesktopPane1 = new javax.swing.JDesktopPane();
        jMenuBar1 = new javax.swing.JMenuBar();
        jMenu1 = new javax.swing.JMenu();
        jMenu2 = new javax.swing.JMenu();
        jMenuItem1 = new javax.swing.JMenuItem();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        javax.swing.GroupLayout jDesktopPane1Layout = new javax.swing.GroupLayout(jDesktopPane1);
        jDesktopPane1.setLayout(jDesktopPane1Layout);
        jDesktopPane1Layout.setHorizontalGroup(
            jDesktopPane1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 376, Short.MAX_VALUE)
        );
        jDesktopPane1Layout.setVerticalGroup(
            jDesktopPane1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 302, Short.MAX_VALUE)
        );

        jMenu1.setText("File");
        jMenuBar1.add(jMenu1);

        jMenu2.setText("About");

        jMenuItem1.setText("About");
        jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jMenuItem1ActionPerformed(evt);
            }
        });
        jMenu2.add(jMenuItem1);

        jMenuBar1.add(jMenu2);

        setJMenuBar(jMenuBar1);

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jDesktopPane1)
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addComponent(jDesktopPane1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap())
        );

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

    private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
        AboutFrame about = new AboutFrame();
        about.setVisible(true);
        jDesktopPane1.add(about);
        try {
            about.setSelected(true);
        } catch (java.beans.PropertyVetoException e) {
        }
    }                                          


    public static void main(String args[]) {

        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }

        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new NewJFrame().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JDesktopPane jDesktopPane1;
    private javax.swing.JMenu jMenu1;
    private javax.swing.JMenu jMenu2;
    private javax.swing.JMenuBar jMenuBar1;
    private javax.swing.JMenuItem jMenuItem1;
    // End of variables declaration                   
}

AboutFrame.java

import java.awt.Dimension;
import java.awt.Graphics;
import javax.swing.JInternalFrame;
import javax.swing.JPanel;

public class AboutFrame extends JInternalFrame{

    public AboutFrame() {
        add(new Panel());
        pack();
    }

    private class Panel extends JPanel {
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);

            g.drawString("About Screen", 100, 100);
        }
        public Dimension getPreferredSize(){
            return new Dimension(300, 300);
        }
    }
}

---

Steps I took

1. Opened a new JFrame form
2. Dragged a JDesktopPane to the main frame and expanded it the size of the frame
3. Dragged a JMenuBar to the top of the frame
4. Dragged a JMenuItem to the JMenuBar
5. Added an event listener to the JMenuItem
6. Added the action code that i provided for you earlier. That's all I did, and it works fine.

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EDIT

A different apprach would be instead of using an JInternalFrame for this. Use a modal JDialog. You can create it the same way you did the JInternalFrame , and show it the same way. This will guarantee you don't get this result. :)