I have this App.mxml:
<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx">
<s:Button id="bt" label="click me"/>
</s:Application>
And this test case:
package flexUnitTests
{
import flexunit.framework.Assert;
public class AppTest
{
[Test]
public function testApp():void
{
var app:App = new App();
Assert.assertNotNull(app.bt);
}
}
}
But app.bt
is null. I want to access the button :(
Short Answer:
The life cycle methods have not run on app; so no createChildren() method was executed in order to create the child component of bt.
Longer Answer:
Things get slightly more complicated with the main application file, as it there is no higher level Flex component in the display hierarchy. I'm unclear on all specifics, but..
I think the Flex Compiler does some magic to set up this component--and the Flex Framework--that help makes the whole app work. You are, in essence, bypassing that work by creating your own instance of the component.