Java Swing help - Overclock.net

dangerousHobo · 11-05-07

I have this sample code to figure out how to use a CardLayout, and I can't see to figure out how to set the default size for the window. The code constructs the GUI a little differently than I learned how to do so, so I think that is part of the problem. If any knows how to do this please let me know. Thanks!

Code:

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

public class CardLayoutDemo implements ItemListener {
    JPanel cards; //a panel that uses CardLayout
    final static String BUTTONPANEL = "Card with JButtons";
    final static String TEXTPANEL = "Card with JTextField";
    
    public void addComponentToPane(Container pane) {
        //Put the JComboBox in a JPanel to get a nicer look.
        JPanel comboBoxPane = new JPanel(); //use FlowLayout
        String comboBoxItems[] = { BUTTONPANEL, TEXTPANEL };
        JComboBox cb = new JComboBox(comboBoxItems);
        cb.setEditable(false);
        cb.addItemListener(this);
        comboBoxPane.add(cb);
        
        //Create the "cards".
        JPanel card1 = new JPanel();
        card1.add(new JButton("Button 1"));
        card1.add(new JButton("Button 2"));
        card1.add(new JButton("Button 3"));
        
        JPanel card2 = new JPanel();
        card2.add(new JTextField("TextField", 20));
        
        //Create the panel that contains the "cards".
        cards = new JPanel(new CardLayout());
        cards.add(card1, BUTTONPANEL);
        cards.add(card2, TEXTPANEL);
        
        pane.add(comboBoxPane, BorderLayout.PAGE_START);
        pane.add(cards, BorderLayout.CENTER);
    }
    
    public void itemStateChanged(ItemEvent evt) {
        CardLayout cl = (CardLayout)(cards.getLayout());
        cl.show(cards, (String)evt.getItem());
    }
    
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event dispatch thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("CardLayoutDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        //Create and set up the content pane.
        CardLayoutDemo demo = new CardLayoutDemo();
        demo.addComponentToPane(frame.getContentPane());
        
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    }
    
    public static void main(String[] args) {
      
        /* Turn off metal's use of bold fonts */
        UIManager.put("swing.boldMetal", Boolean.FALSE);
        
        //Schedule a job for the event dispatch thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

ted · 11-05-07

Put this line of code in after you create the JPanel:

Code:

comboBoxPane.setPreferredSize(new Dimension(400,300));

Or, you can just do frame.setSize(int x, int y); before you setVisible(true);
A couple of suggestions.

dangerousHobo · 11-05-07

Cool, Thanks!
The frame.setSize() didn't work when I first tried it before, but your other suggestion worked.

I found I can do it like so too, which is a bit like how'd I normaly set up a GUI.

Code:

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

public class CardLayoutDemo extends JFrame implements ItemListener {
    JPanel cards; //a panel that uses CardLayout
    final static String BUTTONPANEL = "Card with JButtons";
    final static String TEXTPANEL = "Card with JTextField";
    
    public CardLayoutDemo(){
    	super("Test");
    	this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    	this.addComponentToPane();
    	this.setVisible(true);
    	this.setSize(500, 800);
    }
    
    public void addComponentToPane() {
        //Put the JComboBox in a JPanel to get a nicer look.
        JPanel comboBoxPane = new JPanel(); //use FlowLayout
        String comboBoxItems[] = { BUTTONPANEL, TEXTPANEL };
        JComboBox cb = new JComboBox(comboBoxItems);
        cb.setEditable(false);
        cb.addItemListener(this);
        comboBoxPane.add(cb);
        
        //Create the "cards".
        JPanel card1 = new JPanel();
        card1.add(new JButton("Button 1"));
        card1.add(new JButton("Button 2"));
        card1.add(new JButton("Button 3"));
        
        JPanel card2 = new JPanel();
        card2.add(new JTextField("TextField", 20));
        
        //Create the panel that contains the "cards".
        cards = new JPanel(new CardLayout());
        cards.add(card1, BUTTONPANEL);
        cards.add(card2, TEXTPANEL);
        
        add(comboBoxPane, BorderLayout.PAGE_START);
        add(cards, BorderLayout.CENTER);
    }
    
    public void itemStateChanged(ItemEvent evt) {
        CardLayout cl = (CardLayout)(cards.getLayout());
        cl.show(cards, (String)evt.getItem());
    }
    
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event dispatch thread.
     */
    private static void createAndShowGUI() {
        //Create and set up the window.
      //  JFrame frame = new JFrame("CardLayoutDemo");
    //    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        //Create and set up the content pane.
        CardLayoutDemo demo = new CardLayoutDemo();
  
        
        //Display the window.
        //frame.pack();
       // frame.setVisible(true);
    }
    
    public static void main(String[] args) {
      
        /* Turn off metal's use of bold fonts */
        UIManager.put("swing.boldMetal", Boolean.FALSE);
        
        //Schedule a job for the event dispatch thread:
        //creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

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Java Swing help

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