The following program creates four check boxes. The initial state of the first box is
checked. The status of each check box is displayed. Each time you change the state of a
check box, the status display is updated.
// Demonstrate check boxes.
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*
<applet code="CheckboxDemo" width=250 height=200>
</applet>
*/
public class CheckboxDemo extends Applet implements ItemListener {
String msg = "";
Checkbox winXP, winVista, solaris, mac;
public void init() {
winXP = new Checkbox("Windows XP", null, true);
winVista = new Checkbox("Windows Vista");
solaris = new Checkbox("Solaris");
mac = new Checkbox("Mac OS");
add(winXP);
add(winVista);
add(solaris);
add(mac);
winXP.addItemListener(this);
winVista.addItemListener(this);
solaris.addItemListener(this);
mac.addItemListener(this);
}
public void itemStateChanged(ItemEvent ie) {
repaint();
}
// Display current state of the check boxes.
public void paint(Graphics g) {
msg = "Current state: ";
g.drawString(msg, 6, 80);
msg = " Windows XP: " + winXP.getState();
g.drawString(msg, 6, 100);
msg = " Windows Vista: " + winVista.getState();
g.drawString(msg, 6, 120);
msg = " Solaris: " + solaris.getState();
g.drawString(msg, 6, 140);
msg = " Mac OS: " + mac.getState();
g.drawString(msg, 6, 160);
}
}
Sample output is shown in Figure 24-2.
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