Flex 利用ActionScript接口实现Module模块间的数据通信

Flex 利用ActionScript接口实现Module模块间的数据通信

http://353345996-qq-com.javaeye.com/blog/543139
在面向对象的编程中，我们讲要面向接口编程。面向接口的编程方式从一定程度上解决了相互关联的模块间的紧密耦合问题。以上提到的所有数据传输和共享方式都在不同程度上导致了模块间的紧耦合。不过，Flex提供了一种利用标准的ActionScript接口实现Module模块间数据通信的方式。具体地说，对于Module模块对象和主应用Application对象间的通信，我们可以定义一个ActionScript接口，Module模块对象实现了这个接口中定义的方法和属性，那么主应用Application就可以访问这个接口中定义的属性和方法。接口中定义了Module模块对象和主应用Application需要共享的数据和方法，是两者间共同的一个契约，同时也实现了接口和实现的分离，达到了松耦合的目的。参考以下示例，主应用Application，

<?xml version="1.0"?>
<!-- modules/interfaceexample/Main.mxml -->
<mx:Application xmlns="*" xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
import mx.events.ModuleEvent;
import mx.modules.ModuleManager;
[Bindable]
public var selectedItem:Object;
[Bindable]
public var currentModuleName:String;
private function applyModuleSettings(e:Event):void {
// Cast the ModuleLoader's child to the interface.
// This child is an instance of the module.
// You can now call methods on that instance.
var ichild:* = mod.child as IModuleInterface;
if (mod.child != null) {
// Call setters in the module to adjust its
// appearance when it loads.
ichild.setAdjusterID(myId.text);
ichild.setBackgroundColor(myColor.selectedColor);
} else {
trace("Uh oh. The mod.child property is null");
}
// Set the value of a local variable by calling a method
// on the interface.
currentModuleName = ichild.getModuleName();
}
private function reloadModule():void {
mod.unloadModule();
mod.loadModule();
}
]]>
</mx:Script>
<mx:Form>
<mx:FormItem label="Current Module:">
<mx:Label id="l1" text="{currentModuleName}"/>
</mx:FormItem>
<mx:FormItem label="Adjuster ID:">
<mx:TextInput id="myId" text="Enter your ID"/>
</mx:FormItem>
<mx:FormItem label="Background Color:">
<mx:ColorPicker id="myColor"
selectedColor="0xFFFFFF"
change="reloadModule()"
/>
</mx:FormItem>
</mx:Form>
<mx:Label text="Long Shot Insurance" fontSize="24"/>
<mx:ComboBox
labelField="label"
close="selectedItem=ComboBox(event.target).selectedItem"
>
<mx:dataProvider>
<mx:Object label="Select Module"/>
<mx:Object label="Auto Insurance" module="AutoInsurance.swf"/>
</mx:dataProvider>
</mx:ComboBox>
<mx:Panel width="100%" height="100%">
<mx:ModuleLoader id="mod"
width="100%"
url="{selectedItem.module}"
ready="applyModuleSettings(event)"
/>
</mx:Panel>
<mx:Button id="b1" label="Reload Module" click="reloadModule()"/>
</mx:Application>

接口文件，

// modules/interfaceexample/IModuleInterface
package
{
import flash.events.IEventDispatcher;
public interface IModuleInterface extends IEventDispatcher {
function getModuleName():String;
function setAdjusterID(s:String):void;
function setBackgroundColor(n:Number):void;
}
}

Module模块文件，
<?xml version="1.0"?>
<!-- modules/interfaceexample/AutoInsurance.mxml -->
<mx:Module xmlns:mx="http://www.adobe.com/2006/mxml" width="100%"
height="100%" implements="IModuleInterface">
<mx:Panel id="p1"
title="Auto Insurance"
width="100%"
height="100%"
backgroundColor="{bgcolor}"
>
<mx:Label id="myLabel" text="ID: {adjuster}"/>
</mx:Panel>
<mx:Script>
<![CDATA[
[Bindable]
private var adjuster:String;
[Bindable]
private var bgcolor:Number;
public function setAdjusterID(s:String):void {
adjuster = s;
}
public function setBackgroundColor(n:Number):void {
// Use a bindable property to set values of controls
// in the module. This ensures that the property will be set
// even if Flex applies the property after the module is
// loaded but before it is rendered by the player.
bgcolor = n;
// Don't do this. The backgroundColor style might not be set
// by the time the ModuleLoader triggers the READY
// event:
// p1.setStyle("backgroundColor", n);
}
public function getModuleName():String {
return "Auto Insurance";
}
]]>
</mx:Script>
</mx:Module>