FLEX EVENT

1.事件对象

在基于MXML

事件对象定义了一些任何监听函数都可以访问的属性，如下所示：

 

bubbles

 

 指示事件是否是冒泡事件，即是否从已接收任何侦听器进一步沿事件链向上重新发送该事件对象。

cancelable

 

指示该事件是否是可取消的。

currentTarget        

 

 

 处于活动进程的事件对象。

eventPhase  

 

事件流的当前阶段。                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            

 

Target

事件目标，即发出该事件的对象。

 

 Type

事件类型

2.处理事件的方式

可以通过两种方式在Flex应用程序中处理事件：

2.1在MXML对象声明中使用基于XML属性的事件处理器

   MXML事件处理器使用一个XML属性，其中属性的名称与被处理的事件名称相匹配。XML属性的值是一个能够触发某个操作的ActionScript语句。在基于MXML的事件处理器的生存期中，事件对象的名称始终相同：event（通常以小写形式表示）。

 

 

<mx:Button

click=" { textComponent.text = 'You clicked the button' " label=" Click Me " />

<mx:Text

 

id=" textComponent " />

或者

<mx:Script>

<![CDATA[

      private function clickHandler():void

     {

         textComponent.text ='You clicked the button';

      }

]]>

</mx:Script>

<mx:Button click="clickHandler（） " label="Click Me" />

<mx:Text

 

 

id=" textComponent " />

2.2使用addEventListener（）方法

addEventListener（）是在ActionScript类EventDispatcher中定义的，这个类位于能够分配事件的每个AS类的继承层次结构中。简单来讲，可以从知道如何分配事件的任何对象调用addEventListener（）。

addEventListener（）的第一个参数是要监听的事件名称，如MouseEvent.CLICK="click"， MOUSE_DOWN="mouseDown"，MOUSE_UP="mouseUp"，MOUSE_MOVE="mouseMove"，RIGHT_CLICK="rightClick"，MOUSE_WHEEL="mouseWheel"。

当然也可以使用removeEventListener（）。