此前已经讲解了TextBox与List的应用，那么现在将有一个综合它们两个的程序，功能是选择了相应的list选项就能把当前的屏幕切换成对应的TextBox基本文本屏幕，其实用到的切换结束就是这个语句：display.setCurrent(想要实现的屏幕对象)；然而怎样然按钮监听器知道你选择的是哪个候选项呢，可以用getSelectedIndex()来获得选择的选项序号：switch (((List)d).getSelectedIndex())，以下便给出源代码import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.lcdui.*;

public class ListControl extends MIDlet implements CommandListener {

private final static Command exitCommand = new Command("Exit",Command.EXIT,1);
private final static Command backCommand = new Command("back",Command.BACK,1);
private Display display;
private List mainList;
private TextBox tb;

public ListControl()
{
?? display = Display.getDisplay(this);
?? tb = new TextBox("Terry","9prior",15,0);
?? tb.addCommand(exitCommand);
?? tb.addCommand(backCommand);
?? tb.setCommandListener(this);??
??
}

protected void startApp() throws MIDletStateChangeException
{
?? Image[] imageArray = null;
?? try{
?? Image icon = Image.createImage("/1.png");
?? imageArray = new Image[]{
??? icon,
??? icon,
??? icon???
?? };
?? }catch (java.io.IOException err)
?? {
??? System.out.println("loan ...");
?? }
??
?? String[] stringArray = {
???? "choice 1",
???? "choice 2",
???? "choice 3"
?? };
??
?? mainList = new List("katrina",Choice.IMPLICIT,stringArray,imageArray);
?? mainList.addCommand(exitCommand);
?? mainList.setCommandListener(this);
?? display.setCurrent(mainList);
}

protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
??

}

protected void pauseApp() {
??
}

public void commandAction(Command c, Displayable d)
{
?? if (d.equals(mainList)){ //用equals来判断当前display是什么
???
??? if (c == List.SELECT_COMMAND){
???? if (d.equals(mainList)){
????? switch (((List)d).getSelectedIndex()){/*用getSelectedIndex()来获得选择的选项序号*/
?????
????? case 0:
?????? tb.setString("Text A");
?????? display.setCurrent(tb);
?????? break;
????? case 1:
?????? tb.setString("Text B");
?????? display.setCurrent(tb);
?????? break;
????? case 2:
?????? tb.setString("Text C");
?????? display.setCurrent(tb);
?????? break;
?????
????? }
???? }
????
??? }
?? }else
??? if(c == backCommand){
???? display.setCurrent(mainList);
??? }
??
??
}

?

}