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

public class Multiple_List_MIDlet
    extends MIDlet {

  Display display = Display.getDisplay(this);

  //声明一个代表列表框的List对象
  List currentList;

  /*
   1.构造器
   */
  public Multiple_List_MIDlet() {
    Image aimage = null, bimage = null, cimage = null;
    try {
      aimage = Image.createImage("/icons/background/star.png");
      bimage = Image.createImage("/icons/background/hand.png");
      cimage = Image.createImage("/icons/background/boot.png");
    }
    catch (Exception e) {
      System.out.println(e.getMessage());
    }

    Image[] imageArray = {
        aimage, bimage, cimage};

    String[] stringArray = {
        "选项A", "选项B", "选项C"};

    try {
      currentList = new List("List界面组件", Choice.MULTIPLE,
                             stringArray, imageArray);
    }
    catch (Exception e) {
      System.out.println(e.getMessage());
    }

    display.setCurrent(currentList);

    Check c = new Check();
    c.start();
  }

  /*
   2.检测类
   */
  private class Check
      extends Thread {
    int temp[] = {
        -1, -1, -1};
    public final void run() {
      boolean flag = false;
      while (true) {
        int num = currentList.size();
        for (int i = 0; i < num; i++) {
          if (currentList.isSelected(i)) {
            if (temp[i] != i) {
              temp[i] = i;
              flag = true;
              print();
            }
          }
          else {
            if (temp[i] == i) {
              temp[i] = -1;
              flag = true;
              print();
            }
          }
        }
        try {
          sleep(1);
        }
        catch (Exception e) {
          e.getMessage();
        }
      }
    }

    /*
     3.打印类
     */
    void print() {
      String s = "";
      for (int i = 0; i < temp.length; i++) {
        if (temp[i] != -1) {
          s = s + "选项 " + (temp[i] + 1) + " 被选中！" + "\n";
        }
      }
      Alert info = new Alert("当前选中项：", s, null, AlertType.INFO);
      info.setTimeout(2000);
      display.setCurrent(info);
    }
  }

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

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

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

}