java.lang.InstantiationException: Class not a MIDlet是什么错误，请指教

[dssng]

Unable to create MIDlet FullCanvasTest

java.lang.InstantiationException: Class not a MIDlet

at com.sun.midp.midlet.MIDletState.createMIDlet(+51)

at com.sun.midp.midlet.Selector.run(+22)
是什么原因产生的错误，请高手指教

[goodloop]

源码贴出来看下

[goodloop]

你extends MIDlet了么?

[dssng]

源代码如下： 谢谢大家帮我看看为什么会出上面的错

import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
public class MyGame extends Canvas
implements Runnable
{
int r=0;
int x=50;

int y=50;
int length=5;
public MyGame()
{
Thread t=new Thread(this);
t.start();
}
public void paint(Graphics g)
{
clear(g);
paintAnimation(g,100,10,r);
paintCross(g,x,y,length);
}
public void clear(Graphics g)
{
g.setColor(255,255,255);
g.fillRect(0,0,getWidth(),getHeight());
}
public void paintAnimation(Graphics g,int x,int y,int l)
{
g.setColor(0,0,0);
g.drawRect(x,y,l,l);
}

public void paintCross(Graphics g,int x,int y,int length)
{
g.setColor(255,0,0);
g.drawLine(x-length,y,x+length,y);
g.drawLine(x,y-length,x,y+length);
}
public void run()
{
while(true)
{
r++;
if(r>10)
r=0;
repaint();
}
}
protected void keyPressed(int keycode)
{
switch(getGameAction(keycode))
{
case Canvas.UP:
y=y-2;
break;
case Canvas.DOWN:
y=y+1;
break;
case Canvas.LEFT:
x=x-2;
break;
case Canvas.RIGHT:
x=x+2;
break;
}
}
}
请大家帮忙看看

[goodloop]

你没有继承MIDlet就不可以执行啊
你另外再写一个类
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class CanvasTestMIDlet extends MIDlet{
private Display display;
public CanvasTestMIDlet(){
display=Display.getDisplay(this);
}
public void startApp(){
MyGame gameCanvas = new MyGame();
display.setCurrent(gameCanvas);
}
public void pauseApp(){

}
public void destroyApp(boolean unconditional){

}
}

[goodloop]

记住从CanvasTestMIDlet开始运行程序,WTK中要改变那个类名..

[superego]

这个、错误应该是找不到MIDlet 下的类。。。。。。。。。
你把源嘛贴出来！

[dssng]

问题解决了，非常感谢goodloop(小志)