midlet1.java~52~

J2ME的一个简单例子

package j2me;

import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.Display;
import java.util.Calendar;
import java.util.Date;
import javax.microedition.lcdui.game.TiledLayer;
import java.io.*;

public class MIDlet1 extends MIDlet implements CommandListener{
  public static MIDlet1 midlet;
   Display display;
   Form form = new Form("Container Form");

// 定义列表(主菜单)
    List menu;
// 定义文本框
    TextBox input;
// Item类的组件 (Gauge类表示显示屏幕上的一个条形图)
   Gauge gauge = new Gauge("Your enquiry is being processed", false, 100, 30);
// 定义来自Command类的命令
   static final Command okCommand = new Command("OK",Command.OK,1);
   static final Command backCommand = new Command("Back",Command.BACK,0);
   static final Command exitCommand = new Command("Exit", Command.STOP,2);
   String currentMenu; // 定义串变量以标识当前的窗体名
   DateField date;
   Alert alert=new Alert("My Alert Title","My Message",null,AlertType.INFO);

   public MIDlet1() {
  }

   public void startApp() throws MIDletStateChangeException {

// 得到display对象
     display = Display.getDisplay(this);
// 创建初始菜单并加入项
     menu = new List("Enquiries", Choice.IMPLICIT);
     menu.append("Current Balance ", null);
     menu.append("Fixed Deposit ", null);
     menu.append("Check Status ", null);
// 加入Exit命令到窗体
     menu.addCommand(exitCommand);
     menu.setCommandListener(this);
// 调用mainmenu方法，设置初始屏幕

     mainMenu();
  // 加入计量组件到窗体
  date=new DateField("Select to Date",DateField.DATE_TIME);
  //form.append(date);
}

// mainMenu 方法

void mainMenu() {
  //alert.setTimeout(Alert.FOREVER);
  //display.setCurrent(alert);
  //display.setCurrent(menu);
  Calendar c=Calendar.getInstance();
  Date d=c.getTime();
  DateField df=new DateField("Select to Date",DateField.DATE);
  df.setDate(d);
  form.append(df);
  display.setCurrent(form);
  showTextBox();
 //display.setCurrent(new canvas());
  currentMenu = "Main";
}

public void pauseApp() {
  form = null;
  display = null;
  menu = null;
  input = null;
  gauge = null;
}

// 当MIDlet被撤消是调用

public void destroyApp(boolean unconditional) throws MIDletStateChangeException{
  notifyDestroyed();
}

//显示TextBox组件

public void showTextBox()
{
  //input = new TextBox ("Enter the Check Number:", "", 20, TextField.ANY);
  //input.addCommand(backCommand);
  //input.addCommand(okCommand);
  //input.setCommandListener(this);
  //input.setString("");
  //display.setCurrent(input);
  currentMenu = "input";
  canvas c=new canvas();
  c.addCommand(backCommand);
  c.addCommand(okCommand);
  c.setCommandListener(this);
  c.setTitle("My Games");

  TiledLayer layer=new TiledLayer(3,3,null,20,20);

  Ticker ticker=new Ticker("This Is A Ticker!");
  form.setTicker(ticker);
  display.setCurrent(form);
}

//显示进度指示器屏幕

public void showForm()
{
  form.addCommand(backCommand);
  form.setCommandListener(this);
  display.setCurrent(form);
  currentMenu = "form";
}

//命令激活

public void commandAction(Command c, Displayable d) {
  String label = c.getLabel();
  if (label.equals("Exit")) {
    try{
      destroyApp(true);
    }
    catch (Exception e){}
  }

  else if (label.equals("Back")) {
    if(currentMenu.equals("input") || currentMenu.equals("form")) {
        mainMenu();
      }
  }
  else {
    if (label.equals("OK")) {
      showForm();
    }
    else {
      List down = (List)display.getCurrent();
      switch(down.getSelectedIndex()) {
        case 0: showForm();break;
        case 1: showForm();break;
        case 2: showTextBox();break;
      }
    }
  }
  }
}