如何清空界面的内容

import javax.microedition.midlet.*;

import javax.microedition.lcdui.*;

public class NotifyDemo extends MIDlet implements CommandListener

{

Display display;

Form form;

Command exitCommand;

Command finishedCommand;

public NotifyDemo()

{

display=Display.getDisplay(this);

form=new Form("测试程序结束命令");

form.append("按离开键执行destroyApp(false);/n按结束键执行notifyDestroyed()");

exitCommand=new Command("离开",Command.EXIT,1);

finishedCommand=new Command("结束",Command.EXIT,1);

form.addCommand(exitCommand);

form.addCommand(finishedCommand);

form.setCommandListener(this);

}

public void startApp()

{

display.setCurrent(form);

}

public void pauseApp(){}

public void destroyApp(boolean uncondition)

{

form.append("按离开键执行了destroyApp(false)方法体");

}

public void commandAction(Command cmd,Displayable disp)

{

if(cmd==exitCommand)

destroyApp(false);

else if(cmd==finishedCommand)

{

//destroyApp(false);

notifyDestroyed();

}

}

}

执行后显示如下：



修改一下destroyApp()

public void destroyApp(boolean uncondition)

{

for(int i=0;i<form.size();i++)

form.delete(i);

form.append("按离开键执行了destroyApp(false)方法体");

}