为什么程序老无缘无故退出阿？

[qihuachun001]

各位大虾：
我参照闻怡洋书上的例子，每次程序运行一会儿就自动退出，没有任何提示。
我也不知道怎么回事。
各位，有相似经历的来谈谈，是什么原因？

[ccanhong]

backLayer0 = new TiledLayer(5,5,backImage0,30,30);

看看backImage0图的尺寸是否是（30＊5）＊（30＊5）?顺便查查上面这个类的构造函数是怎么用的

[cuilichen]

你这样说别人很难明白。
把程序贴出来，让大家看看。

[虎叔]

运行结束退出很正常嘛！

[qihuachun001]

具体的代码如下：
package gc7_3;

import javax.microedition.lcdui.game.*;
import javax.microedition.lcdui.*;

/**
* <p>Title: </p>
* <p>Description: </p>
* <p>Copyright: Copyright (c) 2005</p>
* <p>Company: </p>
* @author not attributable
* @version 1.0
*/

public class LayerCanvas extends GameCanvas {
private Graphics g;
private TiledLayer backLayer0;
private Image backImage0;
private int aniCounter = 0;
private int aniStarIndex = 0;
private byte[][] backMap = {
{5,-1,5,-1,-1},
{5,5,5,5,-1},
{4,5,5,5,5},
{4,4,1,5,5},
{4,4,4,4,4}};

public LayerCanvas() {
super(true);
g = this.getGraphics();
try{
backImage0 = Image.createImage("/icons/sky.png");
}catch(Exception e){
e.printStackTrace();
}
backLayer0 = new TiledLayer(5,5,backImage0,30,30);
aniStarIndex = backLayer0.createAnimatedTile(3);
for(int y=0;y<5;y++){
for(int x=0;x<5;x++){
backLayer0.setCell(x,y,backMap[y][x]);
}
}
}

public void ballAction(){
backLayer0.setCell(2,3,aniCounter%2+1);
}

public void starAction(){
if(aniCounter%2 == 0){
backLayer0.setAnimatedTile(aniStarIndex, 3);
}else{
backLayer0.setAnimatedTile(aniStarIndex, 6);
}
}

public void action(){
aniCounter ++;
this.starAction();
this.ballAction();
backLayer0.paint(g);
this.flushGraphics();
}

}

[qihuachun001]

package gc7_3;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class SimpleLayerDemo extends MIDlet implements CommandListener{
private Command exitCommand, actCommand;
private LayerCanvas canvas;

/** Constructor */
public SimpleLayerDemo() {
exitCommand = new Command("Exit",Command.EXIT, 1);
actCommand = new Command("Action",Command.SCREEN,1);

canvas = new LayerCanvas();
canvas.addCommand(actCommand);
canvas.addCommand(exitCommand);
canvas.setCommandListener(this);
}

/** Main method */
public void startApp() {
Display.getDisplay(this).setCurrent(canvas);
}

/** Handle pausing the MIDlet */
public void pauseApp() {
}

/** Handle destroying the MIDlet */
public void destroyApp(boolean unconditional) {
}

/** Quit the MIDlet */
public static void quitApp() {
}

/**Handle command events*/
public void commandAction(Command command, Displayable displayable) {
if(command == exitCommand){
this.destroyApp(false);
this.notifyDestroyed();
}
if(command == actCommand){
canvas.action();
}
}

}

一共2个文件

[qihuachun001]

大家看看，是什么问题？

[qihuachun001]

问题解决，关了诺顿的防火墙就好了