Maximizing JInternalFrame in Java

Question

I am trying to get the maximum size of a JInternalFrame when it starts. I did a web search on this and tried various code suggestions, but they don't seem to work properly on my machine, which runs Java 6 on Windows 7.

I simplified the code below to make it easier to isolate the solution.

Can someone show me how to modify the code below so that the inner frame automatically expands when it is created?

import java.awt.BorderLayout; import java.awt.Dimension; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.KeyEvent; import javax.swing.JDesktopPane; import javax.swing.JFrame; import javax.swing.JInternalFrame; import javax.swing.JLayeredPane; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.KeyStroke; public class MaximizeInternalFrame extends JFrame implements ActionListener{ private static final long serialVersionUID = 1L; JLayeredPane desktop; JInternalFrame internalFrame; public MaximizeInternalFrame() { super("Test To Maximize Internal Frame"); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Make the big window be indented 50 pixels from each edge of the screen. int inset = 50; Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); Dimension screenMinus50 = new Dimension(screenSize.width - inset*2, screenSize.height - inset*2); this.setPreferredSize(screenMinus50); desktop = new JDesktopPane(); setJMenuBar(createMenuBar()); this.add(desktop, BorderLayout.CENTER); this.pack(); this.setSize(screenMinus50); this.setLocationRelativeTo(null); } protected JMenuBar createMenuBar() { JMenuBar menuBar = new JMenuBar(); //Set up the File menu. JMenu FileMenu = new JMenu("File"); FileMenu.setMnemonic(KeyEvent.VK_F); menuBar.add(FileMenu); //Set up the first menu item. JMenuItem menuItem = new JMenuItem("New"); menuItem.setMnemonic(KeyEvent.VK_N); menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N, ActionEvent.ALT_MASK)); menuItem.setActionCommand("new"); menuItem.addActionListener(new OpenListener()); FileMenu.add(menuItem); //Set up the second menu item. menuItem = new JMenuItem("Quit"); menuItem.setMnemonic(KeyEvent.VK_Q); menuItem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_Q, ActionEvent.ALT_MASK)); menuItem.setActionCommand("quit"); menuItem.addActionListener(this); FileMenu.add(menuItem); return menuBar; } class OpenListener implements ActionListener { public void actionPerformed(ActionEvent e) { // create internal frame internalFrame = new JInternalFrame("this internal frame needs to be maximized", true, true, true, true); desktop.add(internalFrame); internalFrame.setSize(internalFrame.getMaximumSize()); internalFrame.pack(); internalFrame.setVisible(true); } } public static void main(String args[]) { MaximizeInternalFrame myParentFrame = new MaximizeInternalFrame(); myParentFrame.setVisible(true); } public void actionPerformed(ActionEvent e) {if ("quit".equals(e.getActionCommand())){System.exit(0);}} } 

Answer 1

Add the following after internalFrame.setVisible(true) :

 try { internalFrame.setMaximum(true); } catch (PropertyVetoException e) { // Vetoed by internalFrame // ... possibly add some handling for this case } 

You can also remove internalFrame.setSize(internalFrame.getMaximumSize());