Editable ItemRenderer for Flex 4 Spark List

One of the nice features of the Flex mx:List component is that you can set the renderers to be editable without having to create a new itemrenderer. With the Spark List (s:List) that option is no longer available. Fortunately it is quite easy to create a custom editable itemrenderer for the List.

Select an item in the left column and change the value, you can see the change events being traced out. Right click to view the source code.

There are three steps making an editable itemrenderer for the Spark List component.

First

Create a custom itemrenderer with a TextInput and a Label.

 <?xml version="1.0" encoding="utf-8"?>
 <s:ItemRenderer xmlns:fx="http://ns.adobe.com/mxml/2009" 
             xmlns:s="library://ns.adobe.com/flex/spark" 
             xmlns:mx="library://ns.adobe.com/flex/mx" 
             autoDrawBackground="true">
 
    
    <s:Label id="labelDisplay" 
           text="{data.label}"   
           top="7" bottom="5" left="5" right="3"/>
    
    <s:TextInput id="inputTxt"  
              visible="false"  
              top="1"  bottom="1" left="1" right="0"/>
    
 </s:ItemRenderer>
  

Second

In order to toggle between the read and write states we need to add a click handler to the label and focusOut handler to the text input. You will notice that I simply set the respecitive components to either visible or not instead of uses the spark states. Using the spark states would require extending the list component to include an editHover state and for this example I wanted to keep things simple.

 <fx:Script>
   <![CDATA[
 	 import spark.components.supportClasses.ListBase;
 	 
 	 private function onChange(event:Event):void 
 	 {
 		isEdit(false);
 		
 	 }
 	 
 	 private function onEdit(event:Event):void 
 	 {
 		inputTxt.text = data.label;
 		isEdit(true);
 		//set cursor postion to end
 		inputTxt.selectRange(inputTxt.text.length,inputTxt.text.length+1);
 		inputTxt.setFocus();
 	 }
 	 
 	 private function isEdit(value:Boolean):void 
 	 {
 		labelDisplay.visible = !value;
 		inputTxt.visible =  value;
 	 }
 	 
   
   ]]>
 </fx:Script>
 
 
 <s:Label id="labelDisplay" 
 	  text="{data.label}"   
 	  click="onEdit(event)" 
 	  top="7" bottom="5" left="5" right="3"/>
 
 <s:TextInput id="inputTxt"  
 		 visible="false"  
 		 focusOut="onChange(event)"
 		 top="1"  bottom="1" left="1" right="0"/>
 
 

Third

This is the not so obvious step. You need to manually dispatch an event through the List’s dataProvider in order to notify the List and anything else that is using the data source that it’s contents have changed.

private function onChange(event:Event):void 
 {
 
 var oldValue:String = labelDisplay.text;
 
 if (oldValue != inputTxt.text)
 {
    data.label = inputTxt.text;
    labelDisplay.text = inputTxt.text;
    
    
    //dispatch the data update event
    var list:ListBase = this.owner as ListBase;
    list.dataProvider.itemUpdated(data, 'label', oldValue, inputTxt.text); 
 }
 isEdit(false);
 
 }

And that’s it. A basic editable list itemrenderer for the Spark List in 3 easy steps. Right click on the swf to see the source code.

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