j-j2me-10-5.shtml

从IBM公司收集到的J2me教程,想要开发手机游戏的朋友,可以参考一下

menu12over.src="imagemaster/himenu12.jpg"; 
menu12out.src="imagemaster/menu12.jpg"; 

        var mainblurb="主菜单";
        var sectionblurb="章节菜单";
        var feedbackblurb="给出此教程的反馈意见";
        var previousblurb="上一屏";
        var nextblurb="下一屏";
        var nextsectionblurb="下一章";

        topmainover.src="../i/h-main.gif";
        topmainout.src="../i/main.gif";
        bottommainover.src="../i/h-main.gif";
        bottommainout.src="../i/main.gif";
        topsectionover.src="../i/h-section.gif";
        topsectionout.src="../i/section.gif";      
        bottomsectionover.src="../i/h-section.gif";
        bottomsectionout.src="../i/section.gif";      
        topfeedbackover.src="../i/h-feedback.gif";
        topfeedbackout.src="../i/feedback.gif";
        bottomfeedbackover.src="../i/h-feedback.gif";
        bottomfeedbackout.src="../i/feedback.gif";
        toppreviousover.src="../i/h-previous.gif";
        toppreviousout.src="../i/previous.gif";
        bottompreviousover.src="../i/h-previous.gif";
        bottompreviousout.src="../i/previous.gif";
        topnextover.src="../i/h-next.gif";
        topnextout.src="../i/next.gif";
        bottomnextover.src="../i/h-next.gif";
        bottomnextout.src="../i/next.gif";
        topnextsectionout.src="../i/nextsection.gif";
        topnextsectionover.src="../i/h-nextsection.gif";
        bottomnextsectionout.src="../i/nextsection.gif";
        bottomnextsectionover.src="../i/h-nextsection.gif";
      }
      function iOut(image)
      {
        if (browser=="N3")document[image].src=eval(image + "out.src");
      }
      function iOver(image)
      {
        if (browser=="N3")document[image].src=eval(image + "over.src");
      }
     // --></script><a href="#navskip"><img border="0" alt="跳至主目录" src="../i/c.gif" width="1" height="1"></a><!--#include virtual="/developerWorks/inc/tuto-inc/tuto-header.inc" --><!--#include virtual="/developerWorks/inc/tuto-inc/tuto-java-header.inc" --><br x="7"><img src="imagemaster/masthead.jpg" alt="J2ME：循序渐进" width="500" height="40"></td>
  <td width="*" valign="bottom" align="right"><a border="0" href="../tutorial.zip"><img alt="下载教程 zip 文件" border="0" src="../i/icon-zip.gif" width="38" height="26"></a><a href=../tutorial_eng/index.shtml target=_blank><img alt="英文原文" border="0" src="../i/icon-source.gif" width="43" height="26"></a></td></tr><tr><td height="2" colspan="2"><img height="2" width="1" src="../i/c.gif"></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD width="150" height="1" bgcolor="#000000" colspan="6"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR><TR><TD background="../i/sw-gold.gif"><a border="0" href="index.shtml" onMouseOver="iOver('topmain'); iOver('bottommain'); self.status=mainblurb; return true;" onMouseOut="iOut('topmain'); iOut('bottommain'); self.status=''; return true;"><img alt="主菜单" border="0" src="../i/main.gif" name="topmain" width="77" height="15"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topsection'); iOver('bottomsection'); self.status=sectionblurb; return true;" onMouseOut="iOut('topsection'); iOut('bottomsection'); self.status=''; return true;" href="index10.shtml"><img alt="章节菜单" border="0" src="../i/section.gif" name="topsection" width="98" height="15"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topfeedback'); iOver('bottomfeedback'); self.status=feedbackblurb; return true;" onMouseOut="iOut('topfeedback'); iOut('bottomfeedback'); self.status=''; return true;" href="j-j2me-12-3.shtml"><img alt="给出此教程的反馈意见" border="0" src="../i/feedback.gif" name="topfeedback" width="80" height="15"></a></TD><TD width="100%" background="../i/sw-gold.gif"><img src="../i/c.gif" width="1" height="1"></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topprevious'); iOver('bottomprevious'); self.status=previousblurb; return true;" onMouseOut="iOut('topprevious'); iOut('bottomprevious'); self.status=''; return true;" href="j-j2me-10-4.shtml"><img alt="上一屏" border="0" src="../i/previous.gif" name="topprevious" width="77" height="15"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topnext'); iOver('bottomnext'); self.status=nextblurb; return true;" onMouseOut="iOut('topnext'); iOut('bottomnext'); self.status=''; return true;" href="j-j2me-10-6.shtml"><img alt="下一屏" border="0" src="../i/next.gif" name="topnext" width="60" height="15"></a></TD></TR></TABLE><table bgcolor="ffffff" cellspacing="0" cellpadding="2" border="0" height="400" width="100%"><tr valign="bottom"><a name="navskip"></a><td height="25" colspan="4"><img border="0" height="25" width="562" src="imagemaster/titlebar10.jpg" alt="第十章：MIDP API"></td></tr><tr><td bgcolor="ffffff" width="15">&nbsp;</td><td bgcolor="ffffff" width="12">&nbsp;</td><td valign="top" align="left" bgcolor="ffffff" width="*"><p><br x="7"><table cellspacing="0" cellpadding="0" border="0"><tr><td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>HelloWorld MIDlet</b></font></td><td width="200" align="right"><nobr><font size="1" face="Verdana, Arial, Helvetica">第 5 页（共 6 页）</font></nobr></td></tr></table><br x="7"><br x="7"><font size="2" face="Verdana, Arial, Helvetica"><p>  
与使用 KJava HelloWorld   
 应用程序一样，这个 MIDlet   
 也会在 MIDP 设备的显示屏上显示 "Hello World!" 和 Exit 按钮，按下该按钮会终止应用程序。
</p><p>HelloWorld.java   
文件以下面的代码行开始，这些代码行导入稍后会在 <code style="font-family: Courier New, Courier, monospace; font-size: 12">HelloWorld</code> 类中使用的类:
</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">
      import javax.microedition.midlet.MIDlet;
      import javax.microedition.lcdui.Command;
      import javax.microedition.lcdui.CommandListener;
      import javax.microedition.lcdui.Display;
      import javax.microedition.lcdui.Displayable;
      import javax.microedition.lcdui.Form;
</code></pre><p>由于 <code style="font-family: Courier New, Courier, monospace; font-size: 12">HelloWorld</code>    
 类是一个 MIDP   
 应用程序，它扩展了 MIDlet。它也实现   
        <code style="font-family: Courier New, Courier, monospace; font-size: 12">CommandListener</code> 接口来处理事件： 
</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">
      public class HelloWorld extends MIDlet implements CommandListener
</code></pre><p>下面的方法是一个缺省构造程序，它创建一个新表单，在上面初始化控件，然后显示出来：
</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">
      private Form form;

      public HelloWorld()
      {
          // Create a new form on which to display our text
         form = new Form("Test App");

         // Add the text "Hello World!" to the form
         form.append("Hello World!");

         // Add a command button labeled "Exit"
         form.addCommand( new Command( "Exit", Command.EXIT, 1 ) );

         // Register this object as a commandListener
         form.setCommandListener( this );
      }              
</code></pre><p>调用 <code style="font-family: Courier New, Courier, monospace; font-size: 12">startApp()</code> 方法启动应用程序与小应用程序的启动方法很象。在 MIDle 的一次执行中它可能会被调用多次。如果 MIDlet 暂停，<code style="font-family: Courier New, Courier, monospace; font-size: 12">pauseApp()</code> 将会被调用。要重新启动 MIDlet，需调用 <code style="font-family: Courier New, Courier, monospace; font-size: 12">startApp()</code>。仅须执行一次的主初始化代码应该放置在构造程序中：
</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">
      public void startApp()
      {
         // Get a reference to the display, and show the form
         Display display = Display.getDisplay(this);
         display.setCurrent( form );
      } 
</code></pre><p>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">pauseApp()</code> 被调用使得 MIDlet 处于暂停状态。在此应用程序中，当进入暂停状态时，我们没执行任何操作；但是我们仍然需要在 MIDlet 中实现 <code style="font-family: Courier New, Courier, monospace; font-size: 12">pauseApp</code> 方法，因为它是父 MIDlet 类中的抽象方法。 
</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">
      public void pauseApp() { }
</code></pre><p>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">destroyApp()</code> 被调用，破坏了 MIDlet 并使其处于销毁状态。在此应用程序中，我们通过将引用设为 <code style="font-family: Courier New, Courier, monospace; font-size: 12">null</code>，释放了对表单的引用。

</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">   
      public void destroyApp(boolean unconditional)
      {
         form = null;
      }
</code></pre><p>
<code style="font-family: Courier New, Courier, monospace; font-size: 12">commandAction()</code> 方法是事件处理程序，被请求实现 <code style="font-family: Courier New, Courier, monospace; font-size: 12">CommandListener</code> 接口。目前，它破坏了应用程序并通知应用程序管理软件 MIDlet 已经完成。
</p><pre><code style="font-family: Courier New, Courier, monospace; font-size: 12">
      public void commandAction(Command c, Displayable d)
         {
            // Destroy this MIDlet
            destroyApp(true);

            // Notify the application management software that this MIDlet
            // has entered the destroyed state
            notifyDestroyed();
         }
</code></pre><br x="7"></font></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD background="../i/sw-gold.gif"><a border="0" href="index.shtml" onMouseOver="iOver('topmain'); iOver('bottommain'); self.status=mainblurb; return true;" onMouseOut="iOut('topmain'); iOut('bottommain'); self.status=''; return true;"><img alt="主菜单" border="0" src="../i/main.gif" name="bottommain" width="77" height="15"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topsection'); iOver('bottomsection'); self.status=sectionblurb; return true;" onMouseOut="iOut('topsection'); iOut('bottomsection'); self.status=''; return true;" href="index10.shtml"><img alt="章节菜单" border="0" src="../i/section.gif" name="bottomsection" width="98" height="15"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topfeedback'); iOver('bottomfeedback'); self.status=feedbackblurb; return true;" onMouseOut="iOut('topfeedback'); iOut('bottomfeedback'); self.status=''; return true;" href="j-j2me-12-3.shtml"><img alt="给出此教程的反馈意见" border="0" src="../i/feedback.gif" name="bottomfeedback" width="80" height="15"></a></TD><TD width="100%" background="../i/sw-gold.gif"><img src="../i/c.gif" width="1" height="1"></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topprevious'); iOver('bottomprevious'); self.status=previousblurb; return true;" onMouseOut="iOut('topprevious'); iOut('bottomprevious'); self.status=''; return true;" href="j-j2me-10-4.shtml"><img alt="上一屏" border="0" src="../i/previous.gif" name="bottomprevious" width="77" height="15"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topnext'); iOver('bottomnext'); self.status=nextblurb; return true;" onMouseOut="iOut('topnext'); iOut('bottomnext'); self.status=''; return true;" href="j-j2me-10-6.shtml"><img alt="下一屏" border="0" src="../i/next.gif" name="bottomnext" width="60" height="15"></a></TD></TR><TR><TD width="150" height="1" bgcolor="#000000" colspan="6"><IMG alt="" height="1" width="150" src="../i/c.gif"></TD></TR></TABLE><!--#include virtual="/developerWorks/inc/tuto-inc/tuto-footer.inc" --></body></html>