使用事件监听器

使用两种方法为按钮添加事件响应：直接为其添加click属性；为整个程序添加事件监听器。

Demo：

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" 
    creationComplete="createListener()">
    <mx:Panel title="Currency Converter" x="20" y="20" width="450" height="150" layout="absolute">
        <mx:Label text="Price in Dollars" x="25" y="37"/>
        <mx:TextInput x="120" y="35" id="txtPrice"/>
        <mx:Label x="120" y="65" id="labResult"/>
        <!--Use click property to register events for button-->
        <!--
        <mx:Button label="Convert to Yen" x="290" y="35" id="btnConvert" click="ConvertCurrency()"/>
        -->
        <mx:Button label="Convert to Yen" x="290" y="35" id="btnConvert"/>
        
    </mx:Panel>
    
    <mx:Script>
        <![CDATA[
            /**//*Event function for click property of Button
            public function ConvertCurrency():void{
                var rate:Number=120;
                var price:Number=Number(txtPrice.text);
                if(isNaN(price))
                {
                    labResult.text="Input a valid number!";
                }else{
                    price=price*rate;
                    labResult.text="Price in Yen:"+String(price);
                }
            }
            */
            public function createListener():void...{
                btnConvert.addEventListener(MouseEvent.CLICK,ConvertCurrency);
            }
            public function ConvertCurrency(e:Event):void...{
                var rate:Number=120;
                var price:Number=Number(txtPrice.text);
                if(isNaN(price))...{
                    labResult.text="Input a valid number!";
                }else...{
                    price=price*rate;
                    labResult.text="Price in Yen:"+String(price);
                }
                
            }
        ]]>
    </mx:Script>
</mx:Application>