在ActionScript中动态创建Flex组件

问题描述

是不是有一些方法可以重写下面的代码，这样我就不需要每一个可以想象的类型的巨大的switch语句了？另外，如果我可以用某种方式替换switch语句来动态地创建新的控件，那么我可以使代码更小，更直接，而且不必预测自定义控件类型的可能性。

之前：

 <？xml version =1.0encoding =utf-8 ？> 
  layout =vertical> 
< mx：Script> 
<！[CDATA [
 import mx.containers.HBox; 
导入mx.controls.Button; 
导入mx.controls.Label; 
 public function CreateControl（event：Event）：void {
 var Type：String = Edit.text; 
 var NewControl：Object; 
 
 switch（Type）{
'mx.controls :: Label'：NewControl = new Label（）; break; 
 case'mx.controls :: Button'：NewControl = new Button（）; break; 
 case'mx.containers :: HBox'：NewControl = new HBox（）; break; 
 ...所有其他类型，包括不可预见的自定义类型
 
 $ b this.addChild（NewControl as DisplayObject）; 
} 
]]> 
< / mx：Script> 
 < mx：TextInput id =Edit/> 
< mx：Button label =Createclick =CreateControl（event）;/> 
< / mx：WindowedApplication> 
  

后：

 <？xml version =1.0encoding =utf-8？> 
  layout =vertical> 
< mx：Script> 
<！[CDATA [
 import mx.containers.HBox; 
导入mx.controls.Button; 
导入mx.controls.Label; 
 public function CreateControl（event：Event）：void {
 var Type：String = Edit.text; 
 
 var NewControl：Object = * ??? *（Type）; 
 
 this.addChild（NewControl as DisplayObject）; 
} 
]]> 
< / mx：Script> 
 < mx：TextInput id =Edit/> 
< mx：Button label =Createclick =CreateControl（event）;/> 
< / mx：WindowedApplication> 
  

解决方案

请看flash.utils.getDefinitionByName（） 。

我还没有运行这个代码，但是你应该可以按照

<$ p公共函数CreateControl（event：Event）：void {
var Type：String = Edit.text;
var controlClass：Class = getDefinitionByName（Type）as Class;

var NewControl：Object = new controlClass（）;

this.addChild（NewControl as DisplayObject）;
}

Isn't there some way to re-write the following code, such that I don't need a gigantic switch statement with every conceivable type? Also, if I can replace the switch statement with some way to dynamically create new controls, then I can make the code smaller, more direct, and don't have to anticipate the possibility of custom control types.

Before:

<?xml version="1.0" encoding="utf-8"?>
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml"
  layout="vertical">
  <mx:Script>
    <![CDATA[
      import mx.containers.HBox;
      import mx.controls.Button;
      import mx.controls.Label;
      public function CreateControl(event:Event):void {
        var Type:String=Edit.text;
        var NewControl:Object;

        switch (Type) {
          case 'mx.controls::Label':NewControl=new Label();break;
          case 'mx.controls::Button':NewControl=new Button();break;
          case 'mx.containers::HBox':NewControl=new HBox();break;
          ... every other type, including unforeseeable custom types
        }

        this.addChild(NewControl as DisplayObject);
      }
    ]]>
  </mx:Script>
  <mx:Label text="Control Type"/>
  <mx:TextInput id="Edit"/>
  <mx:Button label="Create" click="CreateControl(event);"/>
</mx:WindowedApplication>

AFTER:

<?xml version="1.0" encoding="utf-8"?>
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml"
  layout="vertical">
  <mx:Script>
    <![CDATA[
      import mx.containers.HBox;
      import mx.controls.Button;
      import mx.controls.Label;
      public function CreateControl(event:Event):void {
        var Type:String=Edit.text;

        var NewControl:Object= *???*(Type);

        this.addChild(NewControl as DisplayObject);
      }
    ]]>
  </mx:Script>
  <mx:Label text="Control Type"/>
  <mx:TextInput id="Edit"/>
  <mx:Button label="Create" click="CreateControl(event);"/>
</mx:WindowedApplication>

解决方案

Take a look at flash.utils.getDefinitionByName().

I haven't run this code, but you should be able to do something along the lines of

public function CreateControl(event:Event):void {
    var Type:String=Edit.text;
    var controlClass:Class = getDefinitionByName(Type) as Class;

    var NewControl:Object= new controlClass();

    this.addChild(NewControl as DisplayObject);
}

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