itemcommandevent_midlet.java

本光盘是《J2ME无线移动游戏开发》一书的配套光盘

package ch04;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class ItemCommandEvent_MIDlet
    extends MIDlet
    implements CommandListener,
    ItemCommandListener {
  //声明一个窗体对象
  private Form aform;

  //声明一个退出按钮
  private Command exitCommand;

  //声明一个响应超连模式标签按钮
  private Command hllinkCommand;

  //声明一个响应按钮模式标签按钮
  private Command bCommand;

  //声明一个Display对象
  private Display aDisplay;

  //声明一个超连模式标签
  private StringItem hlstringItem;

  //声明一个按钮模式标签
  private StringItem bstringItem;

  //声明一个响应超连模式标签的提示框
  private Alert hlAlert;

  //声明一个响应按钮模式标签的提示框
  private Alert bAlert;

  /*
   1.构造器
   */
  public ItemCommandEvent_MIDlet() {
    exitCommand = new Command("退出", Command.EXIT, 1);
    hllinkCommand = new Command("响应超连模式标签", Command.ITEM, 2);
    bCommand = new Command("响应按钮模式标签", Command.ITEM, 2);

    aform = new Form("ItemCommandListener事件监听器");

    hlstringItem = new StringItem(null, "我是一个超连模式标签", Item.HYPERLINK);
    hlstringItem.setItemCommandListener(this);
    hlstringItem.setDefaultCommand(hllinkCommand);

    bstringItem = new StringItem(null, "我是一个按钮模式标签", Item.BUTTON);
    bstringItem.setItemCommandListener(this);
    bstringItem.setDefaultCommand(bCommand);

    hlAlert = new Alert("HYPERLINK模式StringItem", "你选择了超连模式标签！"
                        , null, AlertType.INFO);
    bAlert = new Alert("BUTTON模式StringItem", "你选择了按钮模式标签！"
                       , null, AlertType.INFO);

    aform.append("请选择一种标签，点击它。");
    aform.append("\n");
    aform.append(hlstringItem);
    aform.append(bstringItem);

    aform.addCommand(exitCommand);
    aform.setCommandListener(this);

    aDisplay = Display.getDisplay(this);
    aDisplay.setCurrent(aform);
  }

  /*
   2.响应按钮事件
   */
  public void commandAction(Command c, Displayable d) {
    if (c == exitCommand) {
      destroyApp(false);
      notifyDestroyed();
    }

  }

  /*
   3.响应条目按钮事件
   */
  public void commandAction(Command c, Item i) {
    if (c == hllinkCommand) {
      aDisplay.setCurrent(hlAlert, aform);
    }
    else if (c == bCommand) {
      aDisplay.setCurrent(bAlert, aform);
    }
  }

  //启动应用程序
  public void startApp() throws MIDletStateChangeException {
  }

  //挂起应用程序
  public void pauseApp() {
  }

  //撤销应用程序
  public void destroyApp(boolean unconditional) {
    notifyDestroyed();
  }

}