Multiple ChoiceGroup

/*--------------------------------------------------
* MultipleChoiceGroup.java
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.com
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class MultipleChoiceGroup extends MIDlet implements ItemStateListener, CommandListener
{
private Display display; // Reference to display object
private Form fmMain; // The main form
private Command cmExit; // A Command to exit the MIDlet
private Command cmView; // View the choice selected
private int selectAllIndex; // Index of the "Select All" option
private ChoiceGroup cgPrefs; // Choice Group of preferences

private int choiceGroupIndex; // Index of choice group on form

public MultipleChoiceGroup()
{
display = Display.getDisplay(this);

// Create a multiple choice group
cgPrefs = new ChoiceGroup("Preferences", Choice.MULTIPLE);

// Append options, with no associated images
cgPrefs.append("Auto Indent", null);
cgPrefs.append("Replace Tabs", null);
cgPrefs.append("Wrap Text", null);
selectAllIndex = cgPrefs.append("Select All", null);

cmExit = new Command("Exit", Command.EXIT, 1);
cmView = new Command("View", Command.SCREEN,2);

// Create Form, add components, listen for events
fmMain = new Form("");
choiceGroupIndex = fmMain.append(cgPrefs);
fmMain.addCommand(cmExit);
fmMain.addCommand(cmView);
fmMain.setCommandListener(this);
fmMain.setItemStateListener(this);
}

public void startApp()
{
display.setCurrent(fmMain);
}

public void pauseApp()
{ }

public void destroyApp(boolean unconditional)
{ }

public void commandAction(Command c, Displayable s)
{
if (c == cmView)
{
boolean selected[] = new boolean[cgPrefs.size()];

// Fill array indicating whether each element is checked
cgPrefs.getSelectedFlags(selected);

for (int i = 0; i < cgPrefs.size(); i++)
System.out.println(cgPrefs.getString(i) + (selected[i] ? ": selected" : ": not selected"));

}
else if (c == cmExit)
{
destroyApp(false);
notifyDestroyed();
}
}

public void itemStateChanged(Item item)
{
if (item == cgPrefs)
{
// Is "Select all" option checked ?
if (cgPrefs.isSelected(selectAllIndex))
{
// Set all checkboxes to true
for (int i = 0; i < cgPrefs.size() - 1; i++)
cgPrefs.setSelectedIndex(i, true);

// Remove the check by "Select All"
cgPrefs.setSelectedIndex(selectAllIndex, false);
}
}
}
}