Macromedia flex 2-migrating applications to flex 2 Manuale Utente

178

Migration Patterns

Using the drag-and-drop feature

When you convert drag-and-drop code, be aware of the following changes:

■

The 

doDrag()

 method takes an additional required attribute, 

mouse_event

. This 

attribute is the MouseEvent object that contains the mouse information for the start of the 
drag.

■

All drag-and-drop-specific events are now DragEvent class events.

■

For a drop target to accept an item for dropping, it must call the 

acceptDragDrop()

 

method, not use the 

event.handled

 property.

The following example lets you drag one of two colored canvases onto a larger canvas to apply 
the color to the larger canvas:

Flex 1.x:

<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">

<mx:Script><![CDATA[

import mx.managers.Dragmanager;
function dragIt(event, text, format) {

var ds:mx.core.DragSource = new mx.core.DragSource();
ds.addData(text, format);
DragManager.doDrag(event.target, ds, mx.containers.Canvas,

{backgroundColor:event.target.getStyle('backgroundColor'),
width:30, height:30});

}
function doDragEnter(event) {

if (event.dragSource.hasFormat('color')) {

event.handled = true;

}

}
function doDragDrop(event) {

var data = event.dragSource.dataForFormat('color');
myCanvas.setStyle("backgroundColor", data);

}

]]></mx:Script>
<mx:HBox>

<mx:Canvas backgroundColor="#FF0000" borderStyle="solid" width="30"

height="30" mouseMove="dragIt(event, 'red', 'color')"/>

<mx:Canvas backgroundColor="#00FF00" borderStyle="solid" width="30"

height="30" mouseMove="dragIt(event, 'green', 'color')"/>

</mx:HBox>
<mx:Label text="Drag the item into this canvas"/>
<mx:Canvas id="myCanvas" backgroundColor="#FFFFFF" borderStyle="solid" 

width="100" height="100" dragEnter="doDragEnter(event)"
dragDrop="doDragDrop(event)"/>

 </mx:Application>