两个TextField的“清除”按钮如何用

import javax.microedition.lcdui.Command;import javax.microedition.lcdui.CommandListener;import javax.microedition.lcdui.Display;import javax.microedition.lcdui.Displayable;import javax.microedition.lcdui.Form;import javax.microedition.lcdui.TextField;import javax.microedition.midlet.MIDlet;import javax.microedition.midlet.MIDletStateChangeException;public class Delete extends MIDlet implements CommandListener{    private Form form = new Form("“清除”要怎么用？请教各位大虾");    private Display dis;    private TextField user = new TextField("用户名：","",20,TextField.ANY );    private TextField pass = new TextField("密码：","",20,TextField.PASSWORD );    private Command cmdDel = new Command("清除",Command.SCREEN,1);    int position;        protected void startApp() throws MIDletStateChangeException {        dis = Display.getDisplay(this);        dis.setCurrent(form);                form.append(user);        form.append(pass);                form.addCommand(cmdDel);        form.setCommandListener(this);    }    public void commandAction(Command c, Displayable d) {                if(c==cmdDel){            if("什么"=="用户名"){                position = user.getCaretPosition();                user.delete(position-1, 1);            }            else if("什么"=="密码"){                position = pass.getCaretPosition();                pass.delete(position-1, 1);            }        }        }    protected void destroyApp(boolean arg0) throws MIDletStateChangeException {        // TODO Auto-generated method stub    }    protected void pauseApp() {        // TODO Auto-generated method stub    }}

    if(c==cmdDel){            if("什么"=="用户名"){                position = user.getCaretPosition();                user.delete(position-1, 1);            }            else if("什么"=="密码"){                position = pass.getCaretPosition();                pass.delete(position-1, 1);            }        }