在Flex的项目渲染器上获取正确刷新工具提示的问题

Question

I'm having the following problem.

I have an ArrayCollection that's acting as the data provider for a tilelist (called favoriteLinksList)

I use an itemRenderer called FavoriteItem as the tilelist's itemRenderer. This FavoriteItem looks like this:

<?xml version="1.0" encoding="utf-8"?>
<mx:VBox xmlns:mx="http://www.adobe.com/2006/mxml"
 width="280" height="163"
 horizontalAlign="center"
 paddingLeft="5" paddingRight="5" paddingTop="0" paddingBottom="0" xmlns:ns1="*">

 <mx:Canvas width="100%" height="100%">
  <mx:Image
   id="thumbnail"
   width="178" height="115"
   source="{data.thumbnail}"
   toolTip = "{data.tooltip}" x="46" y="10"/>

  <mx:Text
   id="title"
   text="{data.tileListTitle}" 
   width="254"
   toolTip="{data.tooltip}" x="10" y="133"/>
 </mx:Canvas>

</mx:VBox>

As you can see, the tooltips for the two items in it are taken from data.tooltip

This works fine.

The problem is refreshing the tooltip when it has changed.

The objects (of type Object) in the ArrayCollection each have a property called tooltip (obviously since that's where the itemRenderer is getting its info from).

When I change this property to its new value, the tooltip of the itemRenderer doesn't change to reflect this.

I tried to set it manually by getting the itemRenderer from the event that is triggered upon clicking one of the items in the tilelist but without success.

Example:

event.itemRenderer.title.toolTip = event.currentTarget.selectedItem.tooltip;

after having updated the tooltip but this gives a compilation error: Access of possibly undefined property title through a reference with static type mx.controls.listClasses:IListItemRenderer.

I also tried performing a refresh() on the favoriteLinksList array collection but this gave mixed results. The tooltip was updated correctly but one of the items (the first one) in the tilelist went missing! This seems to be a Flex bug. The data provider has the same number of elements before and after the refresh and this doesn't happen if I click on the first element in the tilelist.

All help is greatly appreciated.

Answer 1

I would go about doing 2 things

1. that the object is actually bindable and the change is happening and getting to the item renderer

2. possible solution => override the setter for the data property in the item renderer, do not forget to call super.data = value

-

override public function set data(value:Object):void
{
 super.data = value;
 title.toolTip = data.tooltip;
}

stand with a breakpoint in this row, you should be getting to it when the data changes.

Answer 2

Found a solution to my problem.

The favoriteLinksList is bindable and set as the dataProvider of the tileList. However, changes to the individual objects were not being propagated to the itemRenderer.

I thought that there must a change to the favoriteLinksList Array Collection itself.

As mentioned in my question, I already tried using favoriteLinksList.refresh() but this made the first element in the tileList vanish (though it still seemed to be in the Array Collection). A possible bug in Flex perhaps?

Anyway, discovered that a way around this was to perform the following:

favoriteLinksList.setItemAt(favoriteObject, favoriteLinksList.getItemIndex(favoriteObject));

Essentially, I'm setting the item at index X to itself so not actually doing anything but this is enough for the itemRenderer to refresh the data for the itemRenderer.