使你的TextInput组件只能输入数字.

restrict属性学习.
只能输入数字.
示例：

代码：

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2008/05/15/restricting-which-characters-a-user-can-type-in-a-textinput-control-in-flex/ -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
        layout="vertical"
        verticalAlign="middle"
        backgroundColor="white">

    <mx:Script>
        <![CDATA[
            private function textInput_change(evt:Event):void {
                arrColl.addItem(evt);
            }
        ]]>
    </mx:Script>

    <mx:ArrayCollection id="arrColl" />

    <mx:ApplicationControlBar dock="true">
        <mx:TextInput id="textInput"
                restrict="0-9-"
                change="textInput_change(event);" />
    </mx:ApplicationControlBar>

    <mx:DataGrid id="dataGrid"
            dataProvider="{arrColl}"
            width="100%"
            height="100%" />

</mx:Application>

来自：http://blog.flexexamples.com/2008/05/15/restricting-which-characters-a-user-can-type-in-a-textinput-control-in-flex/