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封装多MIDIet程序

摘要: 封装多MIDIet程序

内容: 你可以将多个MIDIet程序存储在一个JAR文件中。设备会自动显示一个MIDIet的菜单，又用户选择运行哪个MIDIet程序。

以下的例子中包含所有你所需要的： 两个简单MIDIet程序的源代码，一个存储在JAR文件中的表单文件（MANIFEST），一个JAVA文件描述符文件（.jad），MIDIet的图象文件（.png），还有一个用于运行MIDIet程序和编译，预检，创建JAR文件的DOS批处理文件。


源代码1：

/*----------------------------------------------------
* www.CoreJ2ME.com
*
* Simple MIDlet1
*---------------------------------------------------*/
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class MIDlet1 extends MIDlet implements CommandListener
{
 private Display display; // Reference to Display object
 private TextBox tbxMain; // A Textbox to display a message
 private Command cmdExit; // A Command to exit the MIDlet

 // The constructor
 public MIDlet1()
 {
 display = Display.getDisplay(this);

 cmdExit = new Command("Exit", Command.SCREEN, 1);

 tbxMain = new TextBox("Welcome", "Core J2ME", 50, 0);
 tbxMain.addCommand(cmdExit);
 tbxMain.setCommandListener(this);
 }

 // Called by application manager to start the MIDlet.
 public void startApp()
 {
 display.setCurrent(tbxMain);
 }

 // A required method
 public void pauseApp()
 { }

 // A required method
 public void destroyApp(boolean unconditional)
 { }

 // Check to see if our Exit command was selected
 public void commandAction(Command c, Displayable s)
 {
 if (c == cmdExit)
 {
  destroyApp(false);
  notifyDestroyed();
 } 
 }
}

源代码2：

/*----------------------------------------------------
* www.CoreJ2ME.com
*
* Simple MIDlet2
*---------------------------------------------------*/

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

public class MIDlet2 extends MIDlet implements CommandListener
{
 private Display display; // Reference to Display object
 private Form frmMain; // The main form
 private TextField txfName; // A text field to prompt for name
 private Command cmdExit; // A Command to exit the MIDlet

 // The constructor
 public MIDlet2()
 {
 display = Display.getDisplay(this);

 cmdExit = new Command("Exit", Command.SCREEN, 1);

 txfName = new TextField("Name:", "", 10, TextField.ANY); 
 
 frmMain = new Form("Sample Form"); 
 frmMain.addCommand(cmdExit);
 frmMain.append(txfName);
 frmMain.setCommandListener(this); 
 }

 // Called by application manager to start the MIDlet.
 public void startApp()
 {
 display.setCurrent(frmMain);
 } 

 // A required method
 public void pauseApp()
 { }

 // A required method
 public void destroyApp(boolean unconditional)
 { }
 
 // Check to see if our Exit command was selected
 public void commandAction(Command c, Displayable s)
 {
 if (c == cmdExit)
 {
  destroyApp(false);
  notifyDestroyed();
 } 
 }
}

-----------------------------------------------------------------------------------------------------------------------

mainfest.mf 文件（要存到JAR文件里）：

MIDlet-Name: TwoMIDlets
MIDlet-Version: 1.0
MIDlet-Vendor: Core J2ME Technology
MIDlet-1: MIDlet1,/image1.png, MIDlet1
MIDlet-2: MIDlet2,/image2.png, MIDlet2
MicroEdition-Configuration: CLDC-1.0
MicroEdition-Profile: MIDP-1.0

----------------------------------------------------------------------------------------------------------------------

MIDlet.jad 文件

MIDlet-Name: TwoMIDlets
MIDlet-Version: 1.0
MIDlet-Vendor: Core J2ME Technology
MIDlet-Description: Packaging multiple MIDlets
MIDlet-Jar-URL: MIDlet.jar
MIDlet-Jar-Size: 3144
MIDlet-1: MIDlet1,/image1.png, MIDlet1
MIDlet-2: MIDlet2,/image2.png, MIDlet2
----------------------------------------------------------------------------------------------------------------------
Emulator的显示结果：
从左向右：
1。显示MIDIet程序的菜单。
2。运行MIDIet 1
3。运行MIDIet 2
IMG http://www.corej2me.com/DeveloperResources/sourcecode/general/multipleMIDlets/screen1.jpg[/IMG]


文章要点：
1． 入口：

MIDlet-1: MIDlet1,/image1.png, MIDlet1
MIDlet-2: MIDlet2,/image2.png, MIDlet2

以上在mainfest和 jad文件中必须是同样的！
2． 你可以省略对图像文件的引用，如下所示：
MIDlet-1: MIDlet1,, MIDlet1
MIDlet-2: MIDlet2,, MIDlet2

3． 下面的属性在jad文件中是可选的：

MIDlet-Description: Packaging multiple MIDlets

4． 以上的例程基于MIDP与 CLDC的1.0.3版本。

-----------------------------------------------------------------------------------------------------------------------------
源代码下载：
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关于翻译作者:

bruceyuki,JAVA C#技术爱好者，现就读于新西兰奥克兰大学，正参与大学的一个AI项目,可以点击http://www.matrix.org.cn/user_view.asp?username=bruceyuki查看他的个人信息

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