timerdemo.java

J2ME的源码！我以前学习J2ME的源码哈！非常适合初学者

package Timer;
import java.util.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.lcdui.*;


public class TimerDemo extends MIDlet implements CommandListener{
	int time=60;
	Display display;
	MyCanvas mycanvas;
	TextField text;
	Command cmdok,cmdpause,cmdback;
	Thread thread;
	 String daojishi;
     
     
	public TimerDemo(){
		super();
		mycanvas=new MyCanvas();
		mycanvas.setFullScreenMode(true);
		TextField text=new TextField("倒数计时器","请输入数字",255,TextField.ANY);
		Command cmdok=new Command("开始倒计时！",Command.SCREEN,0);
		Command cmdback=new Command("回去",Command.BACK,0);
		Command cmdpause=new Command("暂停",Command.SCREEN,0);
		mycanvas.addCommand(cmdok);
		mycanvas.addCommand(cmdback);
		mycanvas.addCommand(cmdpause);
		mycanvas.setCommandListener(this);
	}
	public void commandAction(Command c, Displayable d) {
		if(c==cmdok){
			  thread.start();
			  int time=60;
				if (time>0){
					time--;
					mycanvas.repaint();
		   }
		   else if(c==cmdback){
			   mycanvas.repaint();
		   }
		   else if(c==cmdpause){
			   notifyPaused();
		
	   }
		}}

	protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
		
	}
	protected void pauseApp() {
		
	}
	protected void startApp() throws MIDletStateChangeException {
		display=Display.getDisplay(this);
		display.setCurrent(mycanvas);

	}
	public class MyTimerTask extends TimerTask{
		public void run(){
			mycanvas.repaint();
			
		}
	}
   public class MyCanvas extends Canvas{
	   private Timer timer;
       private MyTimerTask timerTask;
      
      
       
       MyCanvas() {
           timer = new Timer();
           timerTask = new MyTimerTask(); 
           timer.schedule(timerTask, 1000, 1000);
           
       }
	   public void paint(Graphics g){
//		   daojishi=String.valueOf(i); 
		   g.setColor(0,0,0);
		   g.fillRect(0,0,getWidth(),getHeight());
		   g.setColor(0,200,0);
		   Font font=Font.getFont(Font.FACE_PROPORTIONAL, Font.STYLE_BOLD, Font.SIZE_LARGE);
		   g.drawString(String.valueOf(time),0,0,Graphics.TOP|Graphics.LEFT);
		   
	   }
	}

}