Flex - 创建应用程序

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我们将使用 Flash Builder 4.5 来创建 Flex 应用程序。让我们从一个简单的HelloWorld应用程序开始。

步骤 1 – 创建项目

第一步是使用 Flash Builder IDE 创建一个简单的 Flex 项目。使用选项文件 > 新建 > Flex 项目启动项目向导。现在使用向导窗口将您的项目命名为HelloWorld，如下所示：

Create Flex Project Wizard

选择应用程序类型Web（在 Adobe Flash Player 中运行）。但是，如果未选中此选项，则保留其他默认值，然后单击“完成”按钮。项目成功创建后，您的项目资源管理器中将包含以下内容：

Flex Project Structure

以下是所有重要文件夹的简要说明：

文件夹 位置
表格 table-bordered

源代码 (mxml/as 类) 文件。

我们创建了 com/tutorialspoint/client 文件夹结构，其中包含负责客户端 UI 显示的客户端特定 Java 类。
bin-debug

这是输出部分，它代表实际的可部署 Web 应用程序。

History 文件夹包含 Flex 应用程序历史管理的支持文件。

framework_xxx.swf，Flex 应用程序应使用 Flex 框架文件。

HelloWorld.html，Flex 应用程序的包装器/宿主 HTML 文件。

HelloWorld.swf，我们的基于 Flex 的应用程序。

playerProductInstall.swf，Flash Player 快速安装程序。

spark_xxx.swf，Spark 组件支持库。

swfobject.js，负责在 HelloWorld.html 中加载 HelloWorld.swf 的 JavaScript。它检查 Flash Player 版本并将初始化参数传递给 HelloWorld.swf 文件。

textLayout_xxx.swf，文本组件支持库。
html-template

这代表可配置的 Web 应用程序。Flash Builder 将 html-template 中的文件编译到 bin-debug 文件夹。

History 文件夹包含 Flex 应用程序历史管理的支持文件。

index.template.html，Flex 应用程序的包装器/宿主 HTML 文件，其中包含 Flash Builder 特定配置的占位符。在构建过程中编译到 bin-debug 文件夹中的 HelloWorld.html。

playerProductInstall.swf，Flash Player 快速安装程序在构建过程中被复制到 bin-debug 文件夹。

swfobject.js，负责在 HelloWorld.html 中加载 HelloWorld.swf 的 JavaScript。它检查 Flash Player 版本并将初始化参数传递给 HelloWorld.swf 文件，在构建过程中被复制到 bin-debug 文件夹。

步骤 2 – 创建外部 CSS 文件

为html-template文件夹中的包装器 HTML 页面创建一个 CSS 文件styles.css。

html, body { 
   height:100%;
}

body { 
   margin:0; 
   padding:0; 
   overflow:auto; 
   text-align:center;		
}   

object:focus { 
   outline:none; 
}

#flashContent { 
   display:none;	
}

.pluginHeader {
   font-family:Arial, Helvetica, sans-serif;
   font-size:14px;
   color:#9b1204;
   text-decoration:none;
   font-weight:bold;
}

.pluginInstallText {
   font-family:Arial, Helvetica, sans-serif;
   font-size:12px;
   color:#000000;
   line-height:18px;
   font-style:normal;
}

.pluginText { 
   font-family:Arial, Helvetica, sans-serif;
   font-size:12px;
   color:#000000;
   line-height:18px;
   font-style:normal;
}

步骤 3 – 修改包装器 HTML 页面模板

修改html-template文件夹中的包装器 HTML 页面模板index.template.html。Flash Builder 将创建一个默认的包装器 HTML 页面模板html-template/index.template.html，该模板将编译为 HelloWorld.html。

此文件包含 Flash Builder 在编译过程中替换的占位符。例如，Flash Player 版本、应用程序名称等。

让我们修改此文件以在未安装 Flash 插件的情况下显示自定义消息。

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns = "http://www.w3.org/1999/xhtml" lang = "en" xml:lang = "en">
   
   <head>
      <title>${title}</title>
      <meta name = "google" value = "notranslate" />
      <meta http-equiv = "Content-Type" content = "text/html; charset = utf-8" />
      <link rel = "stylesheet" href = "styles.css" type = "text/css"></link>
      <link rel = "stylesheet" type = "text/css" href = "history/history.css" />
      <script type = "text/javascript" table table-bordered = "history/history.js">
      </script>
      <script type = "text/javascript" table table-bordered = "swfobject.js"></script>
      
      <script type = "text/javascript">
         // For version detection, set to min. required Flash Player version,
         //or 0 (or 0.0.0), for no version detection.
         var swfVersionStr = "${version_major}.${version_minor}.${version_revision}";

         // To use express install, set to playerProductInstall.swf,
         //otherwise the empty string.
         var xiSwfUrlStr = "${expressInstallSwf}";
         var flashvars = {};
         var params = {};
         params.quality = "high";
         params.bgcolor = "${bgcolor}";
         params.allowscriptaccess = "sameDomain";
         params.allowfullscreen = "true";
         
         var attributes = {};
         attributes.id = "${application}";
         attributes.name = "${application}";
         attributes.align = "middle";
         swfobject.embedSWF (
            "${swf}.swf", "flashContent",
            "${width}", "${height}",
            swfVersionStr, xiSwfUrlStr,
            flashvars, params, attributes);

         // JavaScript enabled so display the flashContent div in case
         //it is not replaced with a swf object.
         swfobject.createCSS("#flashContent", "display:block;text-align:left;");
      </script>
   </head>
   
   <body>
      <div id = "flashContent">
         <p style = "margin:100px;">

            <table width = "700" cellpadding = "10" cellspacing = "2" border = "0">
               <tr>
                  <td class = "pluginHeader">Flash Player Required</td>
               </tr>
               
               <tr>
                  <td class = "pluginText">The Adobe Flash Player version
                     10.2.0 or greater is required.</td>
               </tr>
               
               <tr>
                  <td class = "pluginInstallText" align = "left">
               
                  <table border = "0" width = "100%">
                     <tr class = "pluginInstallText" >
                        <td>Click here to download and install Adobe Flash Player:</td>
                        <td> </td>
                        <td align = "right">
                           <script type = "text/javascript">
                              var pageHost
                                 = ((document.location.protocol == "https:") ? "https://" : "http://");
                              document.write("<a target = '_blank'"
                                 +" href = 'http://get.adobe.com/flashplayer/'><"
                                 +"img style = 'border-style: none' table table-bordered = '"
                                 +pageHost
                                 +"www.adobe.com/images/shared/download_buttons/get_flash_player.gif'"
                                 +" alt = 'Get Adobe Flash player' /></a>" );
                           </script>
                        </td>
                     </tr>
                  </table>
               </tr>
            </table>
         </p>
      </div>
      
      <noscript>
         <object classid = "clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"
            width = "${width}" height = "${height}" id = "${application}">
            <param name = "movie" value = "${swf}.swf" />
            <param name = "quality" value = "high" />
            <param name = "bgcolor" value = "${bgcolor}" />
            <param name = "allowScriptAccess" value = "sameDomain" />
            <param name = "allowFullScreen" value = "true" />
         
            <!--[if !IE]>-->
            <object type = "application/x-shockwave-flash" data = "${swf}.swf"
               width = "${width}" height = "${height}">
               <param name = "quality" value = "high" />
               <param name = "bgcolor" value = "${bgcolor}" />
               <param name = "allowScriptAccess" value = "sameDomain" />
               <param name = "allowFullScreen" value = "true" />
            <!--<![endif]-->
         
            <!--[if gte IE 6]>-->
               <p>
                  <p style = "margin:100px;">
                     <table width = "700" cellpadding = "10" cellspacing = "2" 
                        border = "0">
                        <tr>
                           <td class = "pluginHeader">Flash Player Required</td>
                        </tr>
                        
                        <tr>
                           <td class = "pluginText">The Adobe Flash Player version
                           10.2.0 or greater is required.</td>
                        </tr>
                        
                        <tr>
                           <td class = "pluginInstallText" align = "left">

                           <table border = "0" width = "100%">
                              <tr class = "pluginInstallText" >
                                 <td>Click here to download and install Adobe Flash 
                                    Player:</td>
                                 <td> </td>
                                 <td align = "right">
                                    <script type = "text/javascript">
                                       var pageHost
                                          = ((document.location.protocol == "https:") ? "https://" : "http://");
                                       document.write("<a target = '_blank'"
                                          +" href = 'http://get.adobe.com/flashplayer/'><"
                                          +"img style = 'border-style: none' table table-bordered = '"
                                          +pageHost
                                          +"www.adobe.com/images/shared/download_buttons/get_flash_player.gif'"
                                          +" alt = 'Get Adobe Flash player' /></a>" );
                                    </script>
                                 </td>
                              </tr>
                           </table>
                        </tr>
                     </table>
                  </p>
               </p>
            <!--<![endif]-->
         
            <p style = "margin:100px;">
               <table width = "700" cellpadding = "10" cellspacing = "2" border = "0">
                  <tr><td class = "pluginHeader">Flash Player Required</td></tr>
                  <tr><td class = "pluginText">The Adobe Flash Player version
                     10.2.0 or greater is required.</td></tr>
                  <tr>
                     <td class = "pluginInstallText" align = "left">
                        <table border = "0" width = "100%">
                           <tr class = "pluginInstallText" >
                              <td>Click here to download and install Adobe Flash 
                                 Player:</td>
                              <td> </td>
                              <td align = "right">
                                 <script type = "text/javascript">
                                    var pageHost
                                       = ((document.location.protocol == "https:") ? "https://" : "http://");
                                    document.write("<a target = '_blank'"
                                       +" href = 'http://get.adobe.com/flashplayer/'><"
                                       +"img style = 'border-style: none' table table-bordered = '"
                                       +pageHost
                                       +"www.adobe.com/images/shared/download_buttons/get_flash_player.gif'"
                                       +" alt = 'Get Adobe Flash player' /></a>" );
                                 </script>
                              </td>
                           </tr>
                        </table>
                     </td>
                  </tr>
               </table>
            </p>
         <!--[if !IE]>-->
         </object>
         <!--<![endif]-->
         </object>
      </noscript>
   </body>
</html>

步骤 4 – 创建内部 CSS 文件

为table tablebordered/com/tutorialspoint文件夹中的HelloWorld.mxml创建一个 CSS 文件Style.css。Flex 为其 UI 控件提供的 CSS 样式与 HTML UI 控件的 CSS 样式类似。

/* CSS file */
@namespace s "library://ns.adobe.com/flex/spark";
@namespace mx "library://ns.adobe.com/flex/mx";

.heading {
   fontFamily: Arial, Helvetica, sans-serif;
   fontSize: 17px;
   color: #9b1204;
   textDecoration:none;
   fontWeight:normal;
}

.button {
   fontWeight: bold;			
}

.container {
   cornerRadius :10;
   horizontalCenter :0;	
   borderColor: #777777;
   verticalCenter:0;
   backgroundColor: #efefef;
}

步骤 5 – 修改入口级类

Flash Builder 将创建一个默认的 mxml 文件table tablebordered/com.tutorialspoint/HelloWorld.mxml，该文件具有应用程序的根标签<application>容器。让我们修改此文件以显示“Hello,World！”：

<?xml version = "1.0" encoding = "utf-8"?>
<s:Application xmlns:fx = "http://ns.adobe.com/mxml/2009"
   xmlns:s = "library://ns.adobe.com/flex/spark"
   xmlns:mx = "library://ns.adobe.com/flex/mx
   width = "100%" height = "100%"
      minWidth = "500" minHeight = "500"
      initialize = "application_initializeHandler(event)">
   
   <fx:Style source = "/com/tutorialspoint/client/Style.css" />
   <fx:Script>
      <![CDATA[
         import mx.controls.Alert;
         import mx.events.FlexEvent;
         protected function btnClickMe_clickHandler(event:MouseEvent):void {
            Alert.show("Hello World!");
         }

         protected function application_initializeHandler(event:FlexEvent):void {
            lblHeader.text = "My Hello World Application";
         }
      ]]>
   </fx:Script>
   
   <s:BorderContainer width = "500" height = "500" id = "mainContainer"
      styleName = "container">
      <s:VGroup width = "100%" height = "100%" gap = "50" horizontalAlign = "center"
         verticalAlign = "middle">
         <s:Label id = "lblHeader" fontSize = "40" color = "0x777777"
            styleName = "heading" />
         <s:Button label = "Click Me!" id = "btnClickMe"
            click = "btnClickMe_clickHandler(event)" styleName = "button" />
      </s:VGroup>
   </s:BorderContainer>
</s:Application>

您可以在同一源目录中创建更多 mxml 或 ActionScript 文件来定义新的应用程序或定义辅助例程。

步骤 6 – 构建应用程序

Flash Builder 默认情况下选中了自动构建。如果存在任何错误，请检查问题视图。完成更改后，您将不会看到任何错误。

步骤 7 – 运行应用程序

现在单击运行应用程序运行应用程序菜单并选择HelloWorld应用程序以运行该应用程序。

Flex Run Button

如果一切正常，您应该会看到浏览器弹出窗口，应用程序启动并运行。如果您的应用程序一切正常，它将产生以下结果：[在线试用]

因为您正在 Flash Player 中运行应用程序，所以它需要为您的浏览器安装 Flash Player 插件。只需按照屏幕上的说明安装插件即可。如果您已经为浏览器设置了 Flash Player 插件，那么您应该能够看到以下输出：

Flex Application Result

恭喜！您已使用Flex实现了您的第一个应用程序。

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