How to know the order of component rendering in Flex

I have a component that has a sub-component they both use a shared variable from the model. The shared variable needs to be set by the parent component before it can be used by the child component. I did like this in the parent component:

<mx:Canvas
    xmlns:mx="library://ns.adobe.com/flex/mx" 
    ...
    creationComplete="group1_completeHandler(event)" >
        ....
        protected function group1_activateHandler(event:Event):void {
           model.myVariable = somet开发者_StackOverflowhing;
        }
   ....
   <components:myCustomComponent>
     ...
   <components:myCustomComponent>
 ...
</mx:Canvas>

But for some reason when the code inside myCustomComponent tries to use myVariable for the first time I get a "null" object error. This means I guess that the child component gets rendered before the group1_activateHandler gets called and consequently myVariable gets set.

What should I do to ensure that the parent container initializes the variable before the child component gets created?

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You should set the variable in initialize() instead of creationComplete() which is invoked after all components are created and rendered.

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I recommend you factor the variable out of the components into a separate code which you can instantiate separately from the actual components. Then use binding to bind your components to this class. This will give you a much cleaner design.