Flex手机项目继承IconItemRenderer自定义List组件

在学习Flex手机项目的过程中，用到了List组件。系统默认的List有两种形式，一种是只显示一行文件的LabelItemRenderer简单样式，另一种为继承了LabelItemRenderer样式的IconItemRenderer样式。后一种相对比较复杂，在每个item中可以添加图片，图标，多行文件等内容。但是如果认真可以发现，后一种还是不能满足各种项目需求，例如想在每个item里添加一个"修改"或“删除”按钮，就不能做到了。本人花了不少时间查找相关资料，以为可以简单通过设置其属性的方法来添加按钮，但是没有找到，想到就来火，看来网络也不是万能的。写下一笔，以填空白。




认真可以发现，其实第二种就是继承了第一种的LabelItemRenderer重新的定义的组件。既然可以通过继承LabelItemRenderer重写，那么也就可以通过继承IconItemRenderer来自定义自己的组件了。好，行动。在FB4.6里，可以通过两种方法来处定义组件，一种是mxml的设计模式，另一种为as的代码模式。这里讲通过写一个as类来继承。新建一种as类，新建类的时候要继承IconItemRenderer，新建createChildren方法，在createChildren方法里动态添加一个button，设置这个button的各个属性，例如x,y,label等，最后利用this.addChild（）方法把这个自定义组件添加到父类中去。

代码如下：

[java] view plaincopyprint?

1. package common 
2. { 
3.     import flash.events.MouseEvent; 
4.      
5.     import spark.components.Button; 
6.     import spark.components.IconItemRenderer; 
7.      
8.     public class MyItem2extends IconItemRenderer 
9.     { 
10.         private var delButton:Button; 
11.         private var editButton:Button; 
12.         public function MyItem2() 
13.         { 
14.             super(); 
15.         } 
16.         /**
17.          * @private
18.          *
19.          * Override this method to create children for your item renderer
20.          */  
21.         override protected function createChildren():void 
22.         { 
23.             super.createChildren(); 
24.             // create any additional children for your item renderer here 
25.             delButton=new Button(); 
26.             delButton.x=this.parent.width-100; 
27.             delButton.y=25; 
28.             delButton.label="删除"; 
29.             delButton.scaleX=0.6; 
30.             delButton.scaleY=0.6; 
31.             delButton.height=35; 
32.             delButton.width=70; 
33.             delButton.addEventListener(MouseEvent.CLICK,delHandleClick); 
34.             this.addChild(delButton); 
35.              
36.             editButton=new Button(); 
37.             editButton.x=this.parent.width-50; 
38.             editButton.y=25; 
39.             editButton.label="修改"; 
40.             editButton.scaleX=0.6; 
41.             editButton.scaleY=0.6; 
42.             editButton.height=35; 
43.             editButton.width=70; 
44.             editButton.addEventListener(MouseEvent.CLICK,editHandleClick); 
45.             this.addChild(editButton); 
46.         } 
47.         private function delHandleClick(event:MouseEvent):void{ 
48.              
49.         } 
50.         private function editHandleClick(event:MouseEvent):void{ 
51.              
52.         } 
53.     } 
54. } 

package common{import flash.events.MouseEvent;import spark.components.Button;import spark.components.IconItemRenderer;public class MyItem2 extends IconItemRenderer{private var delButton:Button;private var editButton:Button;public function MyItem2(){super();}/** * @private *  * Override this method to create children for your item renderer  */override protected function createChildren():void{super.createChildren();// create any additional children for your item renderer heredelButton=new Button();delButton.x=this.parent.width-100;delButton.y=25;delButton.label="删除";delButton.scaleX=0.6;delButton.scaleY=0.6;delButton.height=35;delButton.width=70;delButton.addEventListener(MouseEvent.CLICK,delHandleClick);this.addChild(delButton);editButton=new Button();editButton.x=this.parent.width-50;editButton.y=25;editButton.label="修改";editButton.scaleX=0.6;editButton.scaleY=0.6;editButton.height=35;editButton.width=70;editButton.addEventListener(MouseEvent.CLICK,editHandleClick);this.addChild(editButton);}private function delHandleClick(event:MouseEvent):void{}private function editHandleClick(event:MouseEvent):void{}}}

在上面的类中，每个item添加了一个“修改”及“删除”按钮，接下来，在mxml里引用这个自定义的组件
如下：

[java] view plaincopyprint?

1. <?xml version="1.0" encoding="utf-8"?> 
2. <s:View xmlns:fx="http://ns.adobe.com/mxml/2009"  
3.         xmlns:s="library://ns.adobe.com/flex/spark" title="主页视图" xmlns:common="common.*"> 
4.     <fx:Declarations> 
5.         <!-- 将非可视元素（例如服务、值对象）放在此处 --> 
6.     </fx:Declarations> 
7.      
8.     <s:List width="100%"  
9.             height="100%" 
10.             alternatingItemColors="0xE3E3E3" 
11.             contentBackgroundColor="0xF9F9F9" 
12.             downColor="0x70B2EE" 
13.             selectionColor="0x70B2EE" 
14.             labelField="productName" focusEnabled="false" 
15.             > 
16.         <s:itemRenderer> 
17.             <fx:Component> 
18.                 <common:MyItem2 iconPlaceholder="@Embed('assets/home.png')" 
19.                                 iconField="productIcon" 
20.                                 iconWidth="50"  
21.                                 iconHeight="50"> 
22.                      
23.                 </common:MyItem2> 
24.             </fx:Component> 
25.         </s:itemRenderer> 
26.         <s:dataProvider> 
27.             <s:ArrayList> 
28.                 <fx:Object productIcon="assets/fx.jpg" productName="Flex SDK"  
29.                            productDesc="A highly productive, free, open source framework."/> 
30.                 <fx:Object productIcon="assets/fb.jpg" productName="Flash Builder"  
31.                            productDesc="Designed to help developers rapidly develop RIAs."/> 
32.                 <fx:Object productIcon="assets/fc.jpg" productName="Flash Catalyst"  
33.                            productDesc="An approachable new interaction design tool."/> 
34.             </s:ArrayList> 
35.         </s:dataProvider> 
36.     </s:List> 
37. </s:View> 

<?xml version="1.0" encoding="utf-8"?><s:View xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark" title="主页视图" xmlns:common="common.*"><fx:Declarations><!-- 将非可视元素（例如服务、值对象）放在此处 --></fx:Declarations><s:List width="100%" height="100%"alternatingItemColors="0xE3E3E3"contentBackgroundColor="0xF9F9F9"downColor="0x70B2EE"selectionColor="0x70B2EE"labelField="productName" focusEnabled="false"><s:itemRenderer><fx:Component><common:MyItem2 iconPlaceholder="@Embed('assets/home.png')"iconField="productIcon"iconWidth="50" iconHeight="50"></common:MyItem2></fx:Component></s:itemRenderer><s:dataProvider><s:ArrayList><fx:Object productIcon="assets/fx.jpg" productName="Flex SDK"    productDesc="A highly productive, free, open source framework."/><fx:Object productIcon="assets/fb.jpg" productName="Flash Builder"    productDesc="Designed to help developers rapidly develop RIAs."/><fx:Object productIcon="assets/fc.jpg" productName="Flash Catalyst"    productDesc="An approachable new interaction design tool."/></s:ArrayList></s:dataProvider></s:List></s:View>

效果如下：


怎样，效果还行吧？纠结了两个多星期，终于发现了这个方法，分享下。其实还有另一种方法可以实现，就是添加一个mxml组件，新建的时候要基于IconItemRenderer，然后添加以下代码：

[java] view plaincopyprint?

1. <?xml version="1.0" encoding="utf-8"?> 
2. <s:IconItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009"  
3.                     xmlns:s="library://ns.adobe.com/flex/spark"   
4.                     labelField="title"  
5.                     messageField="message"  
6.                     iconField="ico"  
7.                     iconWidth="64"  
8.                     iconHeight="64" 
9.                     initialize="init()"> 
10.     <fx:Script> 
11.         <![CDATA[ 
12.             import spark.components.Button; 
13.             private var delButton:Button; 
14.             private function init():void{ 
15.                 if(!delButton){ 
16.                     delButton=new Button(); 
17.                     delButton.addEventListener(MouseEvent.CLICK,handleClick); 
18.                     delButton.x=this.parent.width-70; 
19.                     delButton.y=20; 
20.                     delButton.height=30; 
21.                     delButton.width=50; 
22.                     delButton.label="aa"; 
23.                     this.addChild(delButton); 
24.                 } 
25.             } 
26.             private function handleClick(event:MouseEvent):void{ 
27.                  
28.             } 
29.         ]]> 
30.     </fx:Script> 
31. </s:IconItemRenderer> 

<?xml version="1.0" encoding="utf-8"?><s:IconItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" xmlns:s="library://ns.adobe.com/flex/spark"  labelField="title" messageField="message" iconField="ico" iconWidth="64" iconHeight="64"initialize="init()"><fx:Script><![CDATA[import spark.components.Button;private var delButton:Button;private function init():void{if(!delButton){delButton=new Button();delButton.addEventListener(MouseEvent.CLICK,handleClick);delButton.x=this.parent.width-70;delButton.y=20;delButton.height=30;delButton.width=50;delButton.label="aa";this.addChild(delButton);}}private function handleClick(event:MouseEvent):void{}]]></fx:Script></s:IconItemRenderer>

这样同样可以在item里添加一个button按钮。触类旁通，如果想自定义添加一个图片或其它组件，可以通过这两种方法来实现。