midlet1.java

这是郭克华老师的J2ME视频的源代码

package prj14_1;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Graphics;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;

public class MIDlet1 extends MIDlet {
	private BallCanvas bc = new BallCanvas();
	private Display dis;
	protected void startApp() throws MIDletStateChangeException {
		dis = Display.getDisplay(this);
		dis.setCurrent(bc);
	}
	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
		// TODO Auto-generated method stub

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

	}

	class BallCanvas extends Canvas implements Runnable,CommandListener{
		private int left = 50;
		private int top = 50;
		private int d = 100;
		private int DIR = 1;	//1：向下，2：向上
		
		private Command cmdPause = new Command("暂停",Command.SCREEN,1);
		private Command cmdResume = new Command("继续",Command.SCREEN,1);
		
		private Thread th;
		private boolean RUN = true;
		
		public BallCanvas(){
			this.addCommand(cmdPause);
			this.setCommandListener(this);
			th = new Thread(this);
			th.start();
		}
		public void commandAction(Command c,Displayable d){
			if(c==cmdPause){//按下暂停按钮
				this.removeCommand(cmdPause);
				this.addCommand(cmdResume);
				RUN = false;
				th = null;
			}
			else if(c==cmdResume){//按下继续按钮
				this.removeCommand(cmdResume);
				this.addCommand(cmdPause);
				RUN = true;
				th = new Thread(this);
				th.start();
			}
		}
		public void paint(Graphics g){
			g.setColor(0,255,0);//绿色
			g.fillRect(0,0,this.getWidth(),this.getHeight());
			g.setColor(255,0,0);
			g.fillArc(left,top,d,d,0,360);
		}
		public void run(){
			while(RUN){
				if(DIR==1){
					top+=3;
					d--;
					if(top>=this.getHeight()-d){
						DIR = 2;
					}
				}
				if(DIR==2){
					top-=3;
					d++;
					if(top<=50){
						DIR = 1;
					}
				}
				
				repaint();//重画
				try{
					Thread.currentThread().sleep(10);
				}catch(Exception ex){}				
			}
		}
	}

}