flex 驗證－提交模式 源碼解析

一、設定組件的屬性

在組件裡會有這樣的代碼：

public function set XXX(value):void{

      if(this._XXX != value){

          this._XXX=value;

         invalidateProerties();

      }

}

１.調用UIComponent類的invalidateProperties方法：

public function invalidateProperties():void    {        if (!invalidatePropertiesFlag)        {            invalidatePropertiesFlag = true;            if (nestLevel && UIComponentGlobals.layoutManager)                UIComponentGlobals.layoutManager.invalidateProperties(this);        }    }

2.如上述代碼所示，高用LayoutManager的invalidateProperties方法

 public function invalidateProperties(obj:ILayoutManagerClient ):void    {        if (!invalidatePropertiesFlag && systemManager)        {            invalidatePropertiesFlag = true;            if (!listenersAttached)                attachListeners(systemManager);        }        // trace("LayoutManager adding " + Object(obj) + " to invalidatePropertiesQueue");        if (targetLevel <= obj.nestLevel)            invalidateClientPropertiesFlag = true;        invalidatePropertiesQueue.addObject(obj, obj.nestLevel);        // trace("LayoutManager added " + Object(obj) + " to invalidatePropertiesQueue");    }

３.attachlisteners方法給systemManager添加監聽

public function attachListeners(systemManager:ISystemManager):void    {        if (!waitedAFrame)        {            systemManager.addEventListener(Event.ENTER_FRAME, waitAFrame);        }        else        {            systemManager.addEventListener(Event.ENTER_FRAME, doPhasedInstantiationCallback);            if (!usePhasedInstantiation)            {                if (systemManager && (systemManager.stage || usingBridge(systemManager)))                {                    systemManager.addEventListener(Event.RENDER, doPhasedInstantiationCallback);                    if (systemManager.stage)                        systemManager.stage.invalidate();                }            }        }        listenersAttached = true;    }

４.在觸發render事件的時候，回調

 private function doPhasedInstantiationCallback(event:Event):void    {        // if our background processing is suspended, then we shouldn't do any         // validation        if (UIComponentGlobals.callLaterSuspendCount > 0)            return;                systemManager.removeEventListener(Event.ENTER_FRAME, doPhasedInstantiationCallback);        systemManager.removeEventListener(Event.RENDER, doPhasedInstantiationCallback);        if (!UIComponentGlobals.catchCallLaterExceptions)        {            doPhasedInstantiation();        }        else        {            try            {                doPhasedInstantiation();            }            catch(e:Error)            {                // Dispatch a callLaterError dynamic event for Design View.                 var callLaterErrorEvent:DynamicEvent = new DynamicEvent("callLaterError");                callLaterErrorEvent.error = e;                callLaterErrorEvent.source = this; callLaterErrorEvent.object = currentObject;                systemManager.dispatchEvent(callLaterErrorEvent);            }        }currentObject = null;    }

 

private function doPhasedInstantiation():void    {        // trace(">>DoPhasedInstantation");        // If phasing, do only one phase: validateProperties(),        // validateSize(), or validateDisplayList().        if (usePhasedInstantiation)        {            if (invalidatePropertiesFlag)            {                validateProperties();                // The Preloader listens for this event.                systemManager.document.dispatchEvent(                    new Event("validatePropertiesComplete"));            }            else if (invalidateSizeFlag)            {                validateSize();                // The Preloader listens for this event.                systemManager.document.dispatchEvent(                    new Event("validateSizeComplete"));            }            else if (invalidateDisplayListFlag)            {                validateDisplayList();                // The Preloader listens for this event.                systemManager.document.dispatchEvent(                    new Event("validateDisplayListComplete"));            }        }        // Otherwise, do one pass of all three phases.        else        {            if (invalidatePropertiesFlag)                validateProperties();            if (invalidateSizeFlag)                validateSize();            if (invalidateDisplayListFlag)                validateDisplayList();        }        // trace("invalidatePropertiesFlag " + invalidatePropertiesFlag);        // trace("invalidateSizeFlag " + invalidateSizeFlag);        // trace("invalidateDisplayListFlag " + invalidateDisplayListFlag);        if (invalidatePropertiesFlag ||            invalidateSizeFlag ||            invalidateDisplayListFlag)        {            attachListeners(systemManager);        }        else        {            usePhasedInstantiation = false;listenersAttached = false;var obj:ILayoutManagerClient = ILayoutManagerClient(updateCompleteQueue.removeLargest());            while (obj)            {                if (!obj.initialized && obj.processedDescriptors)                    obj.initialized = true;                if (obj.hasEventListener(FlexEvent.UPDATE_COMPLETE))                    obj.dispatchEvent(new FlexEvent(FlexEvent.UPDATE_COMPLETE));                obj.updateCompletePendingFlag = false;                obj = ILayoutManagerClient(updateCompleteQueue.removeLargest());            }            // trace("updateComplete");            dispatchEvent(new FlexEvent(FlexEvent.UPDATE_COMPLETE));        }        // trace("<<DoPhasedInstantation");    }

注釋：

１，在組件調用invalidateProperties()方法後，調用UIComponent的invalideProperties()。

２，再調用LayoutManager的invalidateProperties()方法。

３，給systemManager添加Render事件(必需要stage.invalidate(),此事件才可以觸發)，在將來要更新和呈現顯示列表的時候調用。

４，REnder事件被觸發後，調用UIcomponent的validateProperties()方法。

５，再調用commitProperties()方法。通常在自訂群組件的時候會複寫該方法，將驗證－提交延遲到此方法中。改寫一些屬性，達到局部重新整理的效果。如：

override      protected      function commitProperties(): void      {      super.commitProperties();      if (sourceChanged){      if (! this.image){     image =  new Image();        this.addChild(image);     image.source =  this._source;        } else {     image.source =  this._source;      }     sourceChanged =  false ;      }      if (scaleChanged){      this.imageWidth =  this.imageWidth *   this.scale;      this.imageHeight =  this.imageHeight *+  this.scale;     scaleChanged =  false ;      }         }  

 

 

invalidateSize ----> measure和invalidateDisplayList   --------> updateDisplayList和上述的過程是一樣的。