Event Example 1 : Key Event « J2ME « Java
Event Example 1
/* License
*
* Copyright 1994-2004 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistribution of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistribution in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* Neither the name of Sun Microsystems, Inc. or the names of contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* This software is provided "AS IS," without a warranty of any kind. ALL
* EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
* ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
* OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
* AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
* AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
* DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
* REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
* INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
* OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
* EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
*
* You acknowledge that this software is not designed, licensed or intended
* for use in the design, construction, operation or maintenance of any
* nuclear facility.
*/
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class EventEx1 extends MIDlet implements CommandListener {
// display manager
Display display = null;
// a menu with items
List menu = null; // main menu
// textbox
TextBox input = null;
// command
static final Command backCommand = new Command("Back", Command.BACK, 0);
static final Command mainMenuCommand = new Command("Main", Command.SCREEN, 1);
static final Command exitCommand = new Command("Exit", Command.STOP, 2);
String currentMenu = null;
// constructor.
public EventEx1() {
}
/**
* Start the MIDlet by creating a list of items and associating the
* exit command with it.
*/
public void startApp() throws MIDletStateChangeException {
display = Display.getDisplay(this);
menu = new List("Menu Items", Choice.IMPLICIT);
menu.append("Item1", null);
menu.append("Item2", null);
menu.append("Item3", null);
menu.append("Item4", null);
menu.addCommand(exitCommand);
menu.setCommandListener(this);
mainMenu();
}
public void pauseApp() {
display = null;
menu = null;
input = null;
}
public void destroyApp(boolean unconditional) {
notifyDestroyed();
}
// main menu
void mainMenu() {
display.setCurrent(menu);
currentMenu = "Main";
}
/**
* a generic method that will be called when selected any of
* the items on the list.
*/
public void prepare() {
input = new TextBox("Enter some text: ", "", 5, TextField.ANY);
input.addCommand(backCommand);
input.setCommandListener(this);
input.setString("");
display.setCurrent(input);
}
/**
* Test item1.
*/
public void testItem1() {
prepare();
currentMenu = "item1";
}
/**
* Test item2.
*/
public void testItem2() {
prepare();
currentMenu = "item2";
}
/**
* Test item3.
*/
public void testItem3() {
prepare();
currentMenu = "item3";
}
/**
* Test item4.
*/
public void testItem4() {
prepare();
currentMenu = "item4";
}
/**
* Handle events.
*/
public void commandAction(Command c, Displayable d) {
String label = c.getLabel();
if (label.equals("Exit")) {
destroyApp(true);
} else if (label.equals("Back")) {
if(currentMenu.equals("item1") || currentMenu.equals("item2") ||
currentMenu.equals("item3") || currentMenu.equals("item4")) {
// go back to menu
mainMenu();
}
} else {
List down = (List)display.getCurrent();
switch(down.getSelectedIndex()) {
case 0: testItem1();break;
case 1: testItem2();break;
case 2: testItem3();break;
case 3: testItem4();break;
}
}
}
}
