actionscript-3 - 列表 itemRenderer 拖过检测

Question

如图所示，假设 item1 的 List1 拖到 item iv 的 List2 上，我希望 item iv 检测到拖过状态并突出显示本身，那么如何实现呢？

Answer 1

为每个列表元素附加一个MouseEvent.MOUSE_OVER侦听器，以检查您是否正在拖动任何内容，如果是，则event.target突出显示。

Answer 2

这是我的解决方案和代码：对于List2：

<s:List
itemRenderer="components.MyRenderer"
dragEnter="myDragEnterHandler(event)"
dragOver="myDragOverHandler(event)"
dragExit="myDragExitHandler(event)">
<fx:Script>
    <![CDATA[
        private function myDragEnterHandler(event:DragEvent):void {
            //we shoudld make List2 be drop target
            DragManager.acceptDragDrop(e.currentTarget as IUIComponent);              
        }

        private function myDragOverHandler(event:DragEvent):void {
            var dropIndex:int = calDropIndex(event);
            var element:MyRenderer= calDropItem(dropIndex);
            //undo highlight if there is last over item
            if(lastOverItem) {
               lastOverItem.undoHighlight();            
            }
            //remember the last highlight one and highlight it
            lastOverItem = element;     
            element.highlight(); 
        }

        private function myDragExitHandler(event:DragEvent):void {
             var dropIndex:int = calDropIndex(event);
             var element:MyRenderer= calDropItem(dropIndex);
             element.undoHighlight(); 
        }

        private function calDropIndex(event:DragEvent):int {
             var dropLocation:DropLocation = 
                 event.currentTarget.layout.calculateDropLocation(event);
             var dropIndex:int = dropLocation.dropIndex;
             return dropIndex;
       }

       private function calDropItem(dropIndex:int):MyRenderer{
           var element:IVisualElement;
           if (layout.useVirtualLayout) {
            element = layout.target.getVirtualElementAt(dropIndex);
           } else {
            element = layout.target.getElementAt(dropIndex);
           }
           return element as MyRenderer;
      }
    ]]>
</fx:Script>
</S:List>