Canvas Drag and Drop
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<!-- dragdrop\DandDCanvas.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"
backgroundColor="white">
<s:layout>
<s:VerticalLayout />
</s:layout>
<fx:Script>
import mx.core.DragSource;
import mx.managers.DragManager;
import mx.events.*;
import mx.containers.Canvas;
// Initializes the drag and drop operation.
private function mouseMoveHandler(event:MouseEvent):void {
// Get the drag initiator component from the event object.
var dragInitiator:Canvas=Canvas(event.currentTarget);
// Get the color of the drag initiator component.
var dragColor:int = dragInitiator.getStyle('backgroundColor');
// Create a DragSource object.
var ds:DragSource = new DragSource();
// Add the data to the object.
ds.addData(dragColor, 'color');
// Call the DragManager doDrag() method to start the drag.
DragManager.doDrag(dragInitiator, ds, event);
}
// Called when the user moves the drag indicator onto the drop target.
private function dragEnterHandler(event:DragEvent):void {
// Accept the drag only if the user is dragging data
// identified by the 'color' format value.
if (event.dragSource.hasFormat('color')) {
// Get the drop target component from the event object.
var dropTarget:Canvas=Canvas(event.currentTarget);
// Accept the drop.
DragManager.acceptDragDrop(dropTarget);
}
}
// Called if the target accepts the dragged object and the user
// releases the mouse button while over the Canvas container.
private function dragDropHandler(event:DragEvent):void {
// Get the data identified by the color format
// from the drag source.
var data:Object = event.dragSource.dataForFormat('color');
// Set the canvas color.
myCanvas.setStyle("backgroundColor", data);
}
</fx:Script>
<!--
A horizontal box with red and green canvases that the user can drag.
-->
<mx:HBox>
<mx:Canvas width="30" height="30" backgroundColor="red"
borderStyle="solid" mouseMove="mouseMoveHandler(event);" />
<mx:Canvas width="30" height="30" backgroundColor="green"
borderStyle="solid" mouseMove="mouseMoveHandler(event);" />
</mx:HBox>
<mx:Label text="Drag a color onto the Canvas container." />
<!-- Handles dragEnter and dragDrop events to allow dropping. -->
<mx:Canvas id="myCanvas" width="100" height="100"
backgroundColor="#FFFFFF" borderStyle="solid" dragEnter="dragEnterHandler(event);"
dragDrop="dragDropHandler(event);" />
<mx:Button id="b1" label="Clear Canvas"
click="myCanvas.setStyle('backgroundColor', '0xFFFFFF');" />
</s:Application>
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