HTML向Flex传参

最近有个需求，要在网站中播放一段介绍性的视频，于是做了一个用Flex播放视频的demo。播放视频的代码是以前在网上找的，但是从html页面获得视频地址的时候参数传递问题浪费了很多时间，现整理总结如下：

在Flex中接收参数很简单，通过FlexGlobals.topLevelApplication.parameters或直接用parameters，文档中对parameters的介绍如下：

spark.components.Application.parameters():Object

[只读] 包含表示提供给此 Application 的参数的名称-值对的 Object。

可以使用 for-in 循环来提取 parameters Object 中的所有名称和值。

参数有两个源：Application 的 URL 中的查询字符串和 FlashVars HTML 参数（仅适用于主 Application）的值。

接收参数代码：

privatefunction init():void
{
    if (parameters != null) {
        var source:String = parameters.source as String;
        var param2:String = parameters.test as String;
    }
}

			private function init():void
			{
				if (parameters != null) {
					var source:String = parameters.source as String;
					var param2:String = parameters.test as String;
				}
			}

        parameters 参数有两个来源Url和FlashVars，分别介绍如下：

新建一个Flex应用程序时会同时新建一个html页面，Flex应用是嵌入到html中的。其中包括javascript和<noscript>标签两部分，只有当浏览器不支持javascript时才会执行<noscript>中的代码。

        1.通过url传递参数

这种方式和html url传参一样，swf?param1=param1&param2=param2代码如下：

swfobject.embedSWF(
                "VideoPlayer.swf?source=http://material.157you.com/material/767/dcf_enc.flv&param2=test", "flashContent",
                "500", "500",
                swfVersionStr, xiSwfUrlStr,
                flashvars, params, attributes);

swfobject.embedSWF(
                "VideoPlayer.swf?source=http://material.157you.com/material/767/dcf_enc.flv&param2=test", "flashContent", 
                "500", "500", 
                swfVersionStr, xiSwfUrlStr, 
                flashvars, params, attributes);

<noscript>
    <objectclassid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"width="500"height="500"id="VideoPlayer">
      <paramname="movie"value="VideoPlayer.swf?source=http://material.157you.com/material/767/dcf_enc.flv"/>
      ......
      <!--[if !IE]>-->
      <objecttype="application/x-shockwave-flash"data="VideoPlayer.swf?source=http://material.157you.com/material/767/dcf_enc.flv&param2=test "width="500"height="500">
         .......
      <!--<![endif]-->
      ......
    </object>
<noscript>

<noscript>
	<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="500" height="500" id="VideoPlayer">
      <param name="movie" value="VideoPlayer.swf?source=http://material.157you.com/material/767/dcf_enc.flv" />
      ......
      <!--[if !IE]>-->
      <object type="application/x-shockwave-flash" data="VideoPlayer.swf?source=http://material.157you.com/material/767/dcf_enc.flv&param2=test " width="500" height="500">
         .......
      <!--<![endif]-->
      ......
	</object>
<noscript>

        2.通过FlashVars传递参数

var flashvars = {};
flashvars.source = "http://material.157you.com/material/767/dcf_enc.flv";
flashvars.param2 = "test";

swfobject.embedSWF(
    "VideoPlayer.swf", "flashContent",
    "500", "500",
    swfVersionStr, xiSwfUrlStr,
    flashvars, params, attributes);

            var flashvars = {};
            flashvars.source = "http://material.157you.com/material/767/dcf_enc.flv";
            flashvars.param2 = "test";
            
            swfobject.embedSWF(
                "VideoPlayer.swf", "flashContent", 
                "500", "500", 
                swfVersionStr, xiSwfUrlStr, 
                flashvars, params, attributes);

<noscript>
    <objectclassid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000"width="500"height="500"id="VideoPlayer">
        <paramname="movie"value="VideoPlayer.swf"/>
        <paramname="flashvars"value="source=http://material.157you.com/material/767/dcf_enc.flv&param2=test"/>
     ......
        <!--[if !IE]>-->
        <objecttype="application/x-shockwave-flash"data="VideoPlayer.swf"width="500"height="500">
            <paramname="flashvars"value="source=http://material.157you.com/material/767/dcf_enc.flv&param2=test"/>
            ......
        <!--<![endif]-->
        ......
    </object>
<noscript>

<noscript>
	<object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" width="500" height="500" id="VideoPlayer">
		<param name="movie" value="VideoPlayer.swf" />
		<param name="flashvars" value="source=http://material.157you.com/material/767/dcf_enc.flv&param2=test" />
     ......
		<!--[if !IE]>-->
		<object type="application/x-shockwave-flash" data="VideoPlayer.swf" width="500" height="500">
		    <param name="flashvars" value="source=http://material.157you.com/material/767/dcf_enc.flv&param2=test" />
		    ......
		<!--<![endif]-->
		......
	</object>
<noscript>

注意：当同时使用url和flashvars传参时，如果参数名相同则flashvars的值会覆盖url的值

        以上是通过Flex提供的专门传递参数的方式实现的，还有一种方式也可以实现参数传递，我们知道在Flex中可以调用JS的方法，所以可以在JS中写一个方法，返回值为要传递的参数，这样在Flex中就可以获取到了，这算是曲线救国的一种方法。

JS方法，返回参数params：

function flexParams() {
    var params = {param2:'test'};
    params.source = "http://material.157you.com/material/767/dcf_enc.flv";

    return params;
}

			function flexParams() {
				var params = {param2:'test'};
				params.source = "http://material.157you.com/material/767/dcf_enc.flv";

				return params;
			}

Flex中调用JS方法，获得参数：

privatefunction init():void
{
    var params:Object = ExternalInterface.call("flexParams");

    if (params != null) {
        var source:String = params.source as String;
        var param2:String = params.param2 as String;
    }
}

			private function init():void
			{
				var params:Object = ExternalInterface.call("flexParams");
				
				if (params != null) {
					var source:String = params.source as String;
					var param2:String = params.param2 as String;
				}
			}