Explpicitly handle the dragOver event
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<!-- dragdrop\DandDListToListShowFeedbackSpark.mxml -->
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark" xmlns:mx="library://ns.adobe.com/flex/mx"
creationComplete="initApp();">
<s:layout>
<s:VerticalLayout />
</s:layout>
<fx:Script>
import mx.collections.ArrayCollection;
import mx.events.DragEvent;
import mx.managers.DragManager;
import spark.layouts.supportClasses.DropLocation;
private function initApp():void {
firstList.dataProvider = new ArrayCollection([
{label:"First", data:"1"},
{label:"Second", data:"2"},
{label:"Third", data:"3"},
{label:"Fourth", data:"4"}
]);
secondList.dataProvider = new ArrayCollection([]);
}
// Variable to store original border color.
private var tempBorderColor:uint;
// Flag to indicate that tempBorderColor has been set.
private var borderColorSet:Boolean = false;
private function dragOverHandler(event:DragEvent):void {
// Explpicitly handle the dragOver event.
event.preventDefault();
// Since you are explicitly handling the dragOver event,
// call showDropIndicator() to have the drop target
// display the drop indicator.
// The drop indicator is removed
// automatically for the list controls by the built-in
// event handler for the dragDrop event.
var dropLocal:DropLocation =
event.currentTarget.layout.calculateDropLocation(event);
event.currentTarget.layout.showDropIndicator(dropLocal);
if (event.dragSource.hasFormat("itemsByIndex"))
{
// Set the border to green to indicate that
// this is a drop target.
// Since the dragOver event is dispatched continuosly
// as you move over the drop target, only set it once.
if (borderColorSet == false) {
tempBorderColor = event.currentTarget.getStyle('borderColor');
borderColorSet = true;
}
// Set the drag-feedback indicator based on the
// type of drag-and-drop operation.
event.currentTarget.setStyle('borderColor', 'green');
if (event.ctrlKey) {
DragManager.showFeedback(DragManager.COPY);
return;
}else if (event.shiftKey) {
DragManager.showFeedback(DragManager.LINK);
return;
}else {
DragManager.showFeedback(DragManager.MOVE);
return;
}
}
// Drag not allowed.
DragManager.showFeedback(DragManager.NONE);
}
private function dragDropHandler(event:DragEvent):void {
dragExitHandler(event);
}
// Restore the border color.
private function dragExitHandler(event:DragEvent):void {
event.currentTarget.setStyle('borderColor', tempBorderColor);
borderColorSet = true;
}
</fx:Script>
<s:HGroup id="myHG">
<s:List id="firstList" dragEnabled="true" dragMoveEnabled="true" />
<s:List id="secondList" dropEnabled="true" dragOver="dragOverHandler(event);"
dragDrop="dragExitHandler(event);" dragExit="dragExitHandler(event);" />
</s:HGroup>
<s:Button id="b1" label="Reset" click="initApp();" />
</s:Application>
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