两个TextField的“清除”按钮怎么用？
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); } }