flex DragManager
DragManager 类管理拖放操作，您可以使用它来将数据从 Flex 应用程序中的一个位置移动到另一位置。例如，您可以选择一个对象（如 List 控件中的项目）或一个 Flex 控件（如 Image 控件），然后将其拖至另一个组件进行添加。
1.DragManager.showFeedback(feedback:String):void参数feedback可选值
DragManager.COPY 在拖动鼠标，并按下Crtl键时显示一个带有一个白色加号的绿色圆圈表示可以放置
DragManager.LINK 在拖动鼠标，并按下shift键时出现一个带有白色箭头的圆圈
DragManager.MOVE 仅一个箭头表示当前可以拖放
DragManager.NONE表示不能放置的图标
1.简单的demo
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.controls.Label;
import mx.core.IUIComponent;
import mx.containers.Box;
import mx.containers.Canvas;
import mx.events.DragEvent;
import mx.managers.DragManager;
import mx.core.DragSource;
import mx.core.UIComponent;
private static const FORMAT:String = "box";
private function boxMouseDownHandler(evt:MouseEvent):void{
var iu:Box = evt.currentTarget as Box;
var dragSource:DragSource = new DragSource();
dragSource.addData( iu, FORMAT );
// lbl.setStyle("backgroundColor","red");
DragManager.doDrag( iu, dragSource, evt );
}
private function canvasDragEnterHandler(evt:DragEvent):void{
if(evt.dragSource.hasFormat(FORMAT)){
DragManager.acceptDragDrop(Canvas(evt.currentTarget));
}
}
private function canvasDragHandler(evt:DragEvent):void{
var box:Box = Box(evt.dragInitiator);
box.x = evt.localX;
box.y = evt.localY;
}
]]>
</mx:Script>
<mx:Canvas backgroundColor="0xEEEEEE" width="652" verticalScrollPolicy="off" horizontalScrollPolicy="off" height="320" horizontalCenter="0" verticalCenter="0" dragEnter="canvasDragEnterHandler(event)" dragDrop="canvasDragHandler(event)">
<mx:Box id="box" width="54" height="66" x="80" y="79" mouseDown="boxMouseDownHandler(event)" focusEnabled="true" >
<mx:Image source="file.png" width="41" height="36" x="111" y="121"/>
</mx:Box>
</mx:Canvas>
</mx:Application>
2.拖拽显示拖拽对象的缩略图，遗憾的是DragManager 对拖拽区域控制的不是很好，
效果图：
<?xml version="1.0"?>
<!-- dragdrop\DandDImageProxy.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
//Import classes so you don't have to use full names.
import mx.managers.DragManager;
import mx.core.DragSource;
import mx.events.DragEvent;
import flash.events.MouseEvent;
[Embed(source='1.png')]
public var globeImage:Class;
private function mouseOverHandler(event:MouseEvent):void
{
var dragInitiator:Image=Image(event.currentTarget);
var ds:DragSource = new DragSource();
ds.addData(dragInitiator, "img");
var imageProxy:Image = new Image();
imageProxy.source = globeImage;
imageProxy.height=60;
imageProxy.width=40;
DragManager.doDrag(dragInitiator, ds, event,
imageProxy, -15, -15, 1.00);
}
private function dragEnterHandler(event:DragEvent):void {
if (event.dragSource.hasFormat("img"))
{
DragManager.acceptDragDrop(Canvas(event.currentTarget));
}
}
private function dragDropHandler(event:DragEvent):void {
Image(event.dragInitiator).x =
Canvas(event.currentTarget).mouseX;
Image(event.dragInitiator).y =
Canvas(event.currentTarget).mouseY;
}
]]>
</mx:Script>
<!-- The Canvas is the drag target -->
<mx:Canvas id="v1"
width="500" height="500"
borderStyle="solid"
backgroundColor="#DDDDDD"
dragEnter="dragEnterHandler(event);"
horizontalScrollPolicy="off"
verticalScrollPolicy="off"
dragDrop="dragDropHandler(event);">
<!-- The image is the drag initiator. -->
<mx:Image id="myimg"
source="@Embed(source='1.png')"
mouseMove="mouseOverHandler(event);"/>
</mx:Canvas>
</mx:Application>
3.拖拽显示拖拽对象的缩略图，控制拖拽区域:
<?xml version="1.0"?>
<!-- dragdrop\DandDImageProxy.mxml -->
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
//Import classes so you don't have to use full names.
import mx.managers.DragManager;
import mx.core.DragSource;
import mx.events.DragEvent;
import flash.events.MouseEvent;
[Embed(source='1.png')]
public var globeImage:Class;
private function mouseOverHandler(event:MouseEvent):void
{
var dragInitiator:Image=Image(event.currentTarget);
var ds:DragSource = new DragSource();
ds.addData(dragInitiator, "img");
var imageProxy:Image = new Image();
imageProxy.source = globeImage;
imageProxy.height=60;
imageProxy.width=40;
DragManager.doDrag(dragInitiator, ds, event,
imageProxy, -15, -15, 1.00);
}
private function dragEnterHandler(event:DragEvent):void {
if (event.dragSource.hasFormat("img"))
{
DragManager.acceptDragDrop(Canvas(event.currentTarget));
}
}
private function dragDropHandler(event:DragEvent):void {
Image(event.dragInitiator).x =
Canvas(event.currentTarget).mouseX;
Image(event.dragInitiator).y =
Canvas(event.currentTarget).mouseY;
if(Image(event.dragInitiator).x <0)
{
Image(event.dragInitiator).x =0;
}
if(Image(event.dragInitiator).x >v1.width-Image(event.dragInitiator).width)
{
Image(event.dragInitiator).x =v1.width-Image(event.dragInitiator).width;
}
if(Image(event.dragInitiator).y<0)
{
Image(event.dragInitiator).y=0;
}
if(Image(event.dragInitiator).y>v1.height-Image(event.dragInitiator).height)
{
Image(event.dragInitiator).y=v1.height-Image(event.dragInitiator).height;
}
}
]]>
</mx:Script>
<!-- The Canvas is the drag target -->
<mx:Canvas id="v1"
width="500" height="500"
borderStyle="solid"
backgroundColor="#DDDDDD"
dragEnter="dragEnterHandler(event);"
horizontalScrollPolicy="off"
verticalScrollPolicy="off"
dragDrop="dragDropHandler(event);">
<!-- The image is the drag initiator. -->
<mx:Image id="myimg"
source="@Embed(source='1.png')"
mouseMove="mouseOverHandler(event);"/>
</mx:Canvas>
</mx:Application>
附件（dNdLib.swc.zip ）为google code 上的拖拽包