[flexcoders] Re: Tree Custom Data Descriptor Example Update

Fri, 19 May 2006 12:27:41 -0700


--- In flexcoders@yahoogroups.com, "sufibaba" <[EMAIL PROTECTED]> wrote:
>
> Hi Flex Team,
>
> Wondering if there is a working example for Beta3. The example in the
> docs is not working.
>
> Flex 2.0 Developer's Guide > Building User Interfaces to
> Flex Applications > Using Data Providers and Collections > Creating a
> custom data descriptor
>
> Thanks,
>
> Tim
>

Here's a simple example descriptor that handles XML structures with no frills (no attribute flags, dnd, empty branches, etc) but should demonstrate the concepts.  

Note:  For beta3, you'll probably want to add null checks to get/has/is  methods, but post b3, the descriptor will not be sent null unless its in your dataset.

ExampleTree.mxml
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" >

    <mx:Tree width="250"
             showRoot="true"
             labelField="@label"
             dataDescriptor="{new ExampleDescriptor()}">
        <mx:dataProvider> 
            <mx:XML id="treeDP">  
                <node label="Mail">
                    <node label="Inbox"/>   
                    <node label="PersonalFolder">     
                        <node label="Demo"/>       
                        <node label="Personal"/>        
                        <node label="SavedMail"/>      
                    </node>      
                    <node label="Calendar"/>
                    <node label="Sent"/>
                    <node label="Trash"/>
                </node>  
            </mx:XML>
        </mx:dataProvider>
    </mx:Tree> 
</mx:Application>   


ExampleDescriptor.as
package
{
    import mx.collections.ICollectionView;
    import mx.collections.XMLListCollection;
    import mx.controls.treeClasses.ITreeDataDescriptor;
   
    public class ExampleDescriptor implements ITreeDataDescriptor
    {
        public function ExampleDescriptor()
        {
            super();
        }
       
        public function getChildren(node:Object, model:Object=null):ICollectionView
        {
            return new XMLListCollection(node.*);
        }
       
        public function isBranch(node:Object, model:Object=null):Boolean
        {
            return XMLList(node.*).length() > 0;
        }
       
        public function hasChildren(node:Object, model:Object=null):Boolean
        {
            return isBranch(node, model);
        }
       
        public function getData(node:Object, model:Object=null):Object
        {
            return Object(node);
        }
       
        //Drag and drop support methods below
        public function addChildAt(parent:Object,
                                   newChild:Object,
                                   index:int,
                                   model:Object=null):Boolean
        {
            return false;   
        }
               
        public function removeChildAt(parent:Object,
                                      child:Object,
                                      index:int,
                                      model:Object=null):Boolean
        {
            return false;   
        }
       
    }
}
 



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