spacerdemo.java

图书中的经典例子 好好看看 会有帮助的。java2me版本的

//spacerDemo.java file
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;

public class spacerDemo extends MIDlet implements CommandListener
{
    private Command exitCommand, spacerCommand;
    private Form form;
    public spacerDemo()
    {
        exitCommand =new Command("Exit",Command.EXIT,1);
        spacerCommand =new Command("addSpacer",Command.SCREEN,1);
        
        form = new Form("spacerDemo");
        form.addCommand(exitCommand);
        form.addCommand(spacerCommand);
        //设置命令监听对象
        form.setCommandListener(this);
        //添加Item对象
        form.append("Login");
        form.append(new TextField("Name","",10,TextField.ANY));
        form.append(new TextField("Password","",6,TextField.PASSWORD));
    }
    protected void startApp(  ) throws MIDletStateChangeException
    {
        Display.getDisplay(this).setCurrent(form);
    }

    protected void pauseApp(  )
    {
    }

    protected void destroyApp( boolean p1 )
    {
    }

    public void commandAction(Command c,Displayable d)
    {
        if (c ==exitCommand)
        {
            destroyApp(false);
            notifyDestroyed();
        }
        else if (c ==spacerCommand)
        {
            form.removeCommand(spacerCommand);
            //插入屏幕宽度，高度为5和20象素的Spacer对象
            form.insert(2,new Spacer(form.getWidth(), 5));
            form.insert(1,new Spacer(form.getWidth(),20));
        }

    }
}