Swing Basics

References

java.sun.com/docs/books/tutorial/uiswing/

http://java.sun.com/products/jfc/tsc/articles/architecture/

A basic application frame

import javax.swing.*;

public class AppFrame extends JFrame implements Runnable {

private static final long serialVersionUID = 1L;

public AppFrame() {
setDefaultCloseOperation(EXIT_ON_CLOSE);
setDefaultLookAndFeelDecorated(true);
}

public void run() {
pack();
setVisible(true);
}

public void display() {
SwingUtilities.invokeLater(this);
}

public static void main(String[] args) {
AppFrame app = new AppFrame();
app.setTitle("Test AppFrame");
app.display();
}
}

A basic content panel

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

public class GUI1 extends JPanel implements ActionListener {

private static final long serialVersionUID = 1L;
private Color color = Color.RED;
private Color nextColor = Color.GREEN;

public GUI1() {
Button b = new Button("Change");
b.addActionListener(this);
add(b);
}

public void actionPerformed(ActionEvent ae) {
Color temp = nextColor;
nextColor = color;
color = temp;
repaint();
}

public void paintComponent(Graphics gc) {
super.paintComponent(gc);
Graphics2D gc2d = (Graphics2D) gc;
gc2d.setColor(color);
gc2d.fillOval(20, 20, 50, 50);

}

public static void main(String[] args) {
AppFrame app = new AppFrame();
app.setTitle("GUI 1");
GUI1 gui = new GUI1();
app.setContentPane(gui);
app.display();
}
}

Menus

public class GUI2 extends JPanel implements ActionListener {

private static final long serialVersionUID = 1L;
private Color color = Color.RED;
private Color nextColor = Color.GREEN;

public GUI2() {
Button b = new Button("Change");
b.addActionListener(this);
add(b);
}

private JMenu makeMenu() {
JMenu result = new JMenu("Commands");
result.setMnemonic('c');
JMenuItem item = new JMenuItem("Change", 'h');
item.addActionListener(this);
result.add(item);
item = new JMenuItem("Exit", 'x');
item.addActionListener(this);
result.add(item);
return result;
}

public void actionPerformed(ActionEvent ae) {
String cmmd = ae.getActionCommand();
if (cmmd.equals("Change")) {
Color temp = nextColor;
nextColor = color;
color = temp;
repaint();
} else if (cmmd.equals("Exit")) {
System.exit(0);
}
}

public void paintComponent(Graphics gc) {
super.paintComponent(gc);
Graphics2D gc2d = (Graphics2D) gc;
gc2d.setColor(color);
gc2d.fillOval(20, 20, 50, 50);

}

public static void main(String[] args) {
AppFrame app = new AppFrame();
app.setTitle("GUI 2");
GUI2 gui = new GUI2();
JMenuBar menuBar = new JMenuBar();
menuBar.add(gui.makeMenu());
app.setJMenuBar(menuBar);
app.setContentPane(gui);
app.display();
}
}