Flex3基礎教程（3）

—Flex3事件機制鄭巖峰2008-5-211精選2021版課件觀察者模式(Observer)什么是觀察者模式？生活中的觀察者模式（好萊塢原則、訂閱報紙、房產(chǎn)中介…）AS3中事件例子:button.addEventListener(“click”,onClick);internalfunctiononClick(evt:MouseEvent):void{ txt.text=“clickabutton!”; }2精選2021版課件事件機制類繼承圖ObjectEventDispatcherDisplayObjectAVMiMovieVideoStaticTextShapeMorphShapeInteractiveObjectBitmapDisplayObjectContainerSimpleButtonTextFieldLoaderSpriteStageMovieClipUIComponent3精選2021版課件事件流1.捕獲事件（從根節(jié)點到子節(jié)點，檢測對象是否注冊了監(jiān)聽器，是則調(diào)用監(jiān)聽函數(shù)）2.目標階段（調(diào)用目標對象本身注冊的監(jiān)聽程序）3.冒泡階段（從目標節(jié)點到根節(jié)點，檢測對象是否注冊了監(jiān)聽器，是則調(diào)用監(jiān)聽函數(shù)）注：事件發(fā)生后，每個節(jié)點可以有2個機會（2選1）響應事件，默認關閉捕獲階段。4精選2021版課件IEventDispatcher接口addEventListener()注冊事件監(jiān)聽器removeEventListener()移除事件監(jiān)聽器dispatchEvent()派發(fā)事件EventDispatcher類，見參考手冊5精選2021版課件addEventListeneraddEvnetListener(type:String,listener:Function,useCapture:Boolean=false,priority:int=0,useWeakReference:Boolean=false)removeEventListener(type:String,listener:Function,useCapture:Boolean=false)6精選2021版課件Event對象Event類作為創(chuàng)建Event對象的基類，當發(fā)生事件時，Event對象將作為參數(shù)傳遞給事件偵聽器。MouseEventKeyboardEvent查參考手冊7精選2021版課件如何自定義事件1.創(chuàng)建自定義事件名稱的Event dispatchEvent(newEvent(“myEvnet”,true,false);2.創(chuàng)建自定義事件類 PublicclassMyEventextendsEvent{ …. }8精選2021版課件拖曳事件的實現(xiàn)D