TileList dataProvider problem

Question

I use removeAll function to clean the dataProvider then I additem to it.
There is an error occured. Because the dataProvider is null !
So I recreate the dataProvider the error still there Why ~~?
this is the code:
var i:int = 0;
   if( TileList.dataProvider )
    TileList.dataProvider.removeAll(); // I remove all items.
   else{  // next time I try to recreate it but I still can't add item to the dataprovider
     // TileList.dataProvider.addItem("Class 1"); I can't do it because the dataprovider is null now
    TileList.dataProvider = new ListCollectionView( );
    while( i++ < 15 ){
     TileList.dataProvider.addItem("Class" + i);

Answer 1

Hmm.. It seems that the data provider is not getting instanciated, which is resulating into null object reference error. I tried out the following code.
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
                layout="absolute">
    <mx:Script>
        <![CDATA[
            import flash.text.engine.ContentElement;
            import mx.collections.ArrayCollection;
            public function btnClick():void
                var i:int=0;
                if (contentList.dataProvider.length > 0)
                    contentList.dataProvider.removeAll();
                else
                    contentList.dataProvider=new ArrayCollection();
                    while (i++ < 15)
                        contentList.dataProvider.addItem("Class" + i);
        ]]>
    </mx:Script>
    <mx:Canvas width="100%"
               height="100%">
        <mx:TileList id="contentList"
                     visible="true"
                     width="50%"
                     height="50%"
                     horizontalCenter="0"
                     bottom="10"
                     horizontalScrollPolicy="off"
                     verticalScrollPolicy="off"
                     verticalAlign="middle"
                     maxColumns="3"
                     maxRows="5"
                     rowHeight="{contentList.height*0.20}"
                     columnWidth="{contentList.width*0.33}"
                     dataProvider="{new ArrayCollection()}">
        </mx:TileList>
        <mx:Button id="btn"
                   label="Populate Tile List"
                   width="{btn.label.length * 8}"
                   height="20"
                   click="btnClick()">
        </mx:Button>
    </mx:Canvas>
</mx:Application>
May be this will help you.
Thanks and Regards,
Pooja Kuber | [email protected] | www.infocepts.com