midlet7.java

这是郭克华老师的J2ME视频的源代码

package prj8_1;

import java.util.Date;

import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.TextBox;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class MIDlet7 extends MIDlet implements CommandListener{

	private TextBox tbx = new TextBox("输入一个数字","",10,TextField.ANY);
	private Display dis;
	private Command cmd = new Command("打印平方",Command.SCREEN,1);
	
	public MIDlet7() {
		// TODO Auto-generated constructor stub
	}
	protected void startApp() throws MIDletStateChangeException {
		// TODO Auto-generated method stub
		dis = Display.getDisplay(this);
		dis.setCurrent(tbx);
		tbx.addCommand(cmd);
		
		tbx.setCommandListener(this);
		
		Image img = Image.createImage("/file");
	}
	
	public void commandAction(Command c,Displayable d){
		String str = tbx.getString();
		try{
			this.print(str);
		}catch(CustomException ce){
			System.out.println(ce.getMessage());
			System.out.println(ce.getDate());
		}
	}
	
	public void print(String str) throws CustomException{//表示这个函数可能要抛出异常给客户端
		try{
			int intValue = Integer.parseInt(str);
			int result = intValue * intValue;
			System.out.println("平方是:" + result);
		}
		catch(Exception ex){
			CustomException ce = new CustomException("格式错误",new Date());
			throw ce;	//将ce抛给客户端
		}

	}
		
	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
		// TODO Auto-generated method stub

	}
	protected void pauseApp() {
		// TODO Auto-generated method stub

	}
}
class CustomException extends Exception{//自定义异常
	private Date date;
	public CustomException(String message,Date date){
		super(message);
		this.date = date;
	}
	public Date getDate(){
		return this.date;
	}
}