函数
protected void keyPressed(int keyCode) {
}
让我们能够使用手机数字键
下面是我编写的一个实例，由两个文件组成：

//liuy002.java
package example.liuy.liuy002;

import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class liuy002 extends MIDlet {

/**
* @see MIDlet#startApp()
*/
protected void startApp() throws MIDletStateChangeException {
Display d = Display.getDisplay(this);
keytest f = new keytest();
d.setCurrent(f);
}

/**
* @see MIDlet#pauseApp()
*/
protected void pauseApp() {
}

/**
* @see MIDlet#destroyApp(boolean)
*/
protected void destroyApp(boolean flag) throws MIDletStateChangeException {
}
}

//keytest.java
package example.liuy.liuy002;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Graphics;

public class keytest extends Canvas {

/**
* Constructor for keytest
*/
String aMessage = "[请按键]";


protected keytest() {
super();
}

/**
* @see Canvas#paint(Graphics)
*/
protected void paint(Graphics g) {

g.drawString(aMessage,10,10,Graphics.TOP|Graphics.LEFT);

}
protected void keyPressed(int keyCode) {

aMessage = getKeyName(keyCode);
aMessage = "数字"+aMessage+"已被按下";
repaint();

}

}