Low-Level Display Canvas:Key Code Example
/*
J2ME: The Complete Reference
James Keogh
Publisher: McGraw-Hill
ISBN 0072227109
*/
//jad file (please verify the jar size)
/*
MIDlet-Name: KeyCodeExample
MIDlet-Version: 1.0
MIDlet-Vendor: MyCompany
MIDlet-Jar-URL: KeyCodeExample.jar
MIDlet-1: KeyCodeExample, , KeyCodeExample
MicroEdition-Configuration: CLDC-1.0
MicroEdition-Profile: MIDP-1.0
MIDlet-JAR-SIZE: 100
*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
public class KeyCodeExample extends MIDlet
{
private Display display;
private MyCanvas canvas;
public KeyCodeExample ()
{
display = Display.getDisplay(this);
canvas = new MyCanvas(this);
}
protected void startApp()
{
display.setCurrent(canvas);
}
protected void pauseApp()
{
}
protected void destroyApp( boolean unconditional )
{
}
public void exitMIDlet()
{
destroyApp(true);
notifyDestroyed();
}
}
class MyCanvas extends Canvas implements CommandListener
{
private Command exit;
private String direction;
private KeyCodeExample keyCodeExample;
public MyCanvas (KeyCodeExample keyCodeExample)
{
direction = "2=up 8=dn 4=lt 6=rt";
this.keyCodeExample = keyCodeExample;
exit = new Command("Exit", Command.EXIT, 1);
addCommand(exit);
setCommandListener(this);
}
protected void paint(Graphics graphics)
{
graphics.setColor(255,255,255);
graphics.fillRect(0, 0, getWidth(), getHeight());
graphics.setColor(255, 0, 0);
graphics.drawString(direction, 0, 0,
Graphics.TOP | Graphics.LEFT);
}
public void commandAction(Command command, Displayable displayable)
{
if (command == exit)
{
keyCodeExample.exitMIDlet();
}
}
protected void keyPressed(int key)
{
switch ( key ){
case KEY_NUM2:
direction = "up";
break;
case KEY_NUM8:
direction = "down";
break;
case KEY_NUM4:
direction = "left";
break;
case KEY_NUM6:
direction = "right";
break;
}
repaint();
}
}
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