CODEWITHSUNDEEP
actionscript-3apache-flexflash-buildermxml
SimonRH
SimonRH

Reputation: 1469

Why will UIComponent not show content?

The code below works. However, If I change the container in the component from a Canvas to a UIComponent the Canvas inside the container does not show. Why is this the case?

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

Comp.mxml

<mx:Canvas   xmlns:mx = "http://www.adobe.com/2006/mxml"  buttonMode="true" useHandCursor="true"  >
    <mx:Canvas  width="100" height="100" backgroundColor="0xffff00"  />
</mx:Canvas>

Upvotes: 0

Views: 125

Answers (2)

JeffryHouser
JeffryHouser

Reputation: 39408

Because the UIComponent does not implement a measure() or updateDisplayList() method, and therefore your component is never given a size; thus there is no visual display area for the child component to be shown.

Please read up on the Flex Component LifeCycle

Upvotes: 1

tensorcrow
tensorcrow

Reputation: 68

Here is the quotation from the UIComponent spec:

The UIComponent class is not used as an MXML tag, but is used as a base class for other classes.

For details, see UIComponen specification here: http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/mx/core/UIComponent.html

Upvotes: 0

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