Flex mxml custom component - how to add uicomponents? - apache-flex

Question

how to I pass in a uicomponent to a mxml custom component?
ex: I want to pass in any number of buttons, and I want my custom component to lay them out in a certain order.
MainApp.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"
minWidth="955" minHeight="600" xmlns:local="*"
>
<local:myComp >
<s:Button label='Button1' />
<s:Button label='Button2' />
<!--I want to add anything else here -->
</local:myComp>
myComp.mxml:
<?xml version="1.0" encoding="utf-8"?>
<s:Group xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark"
xmlns:mx="library://ns.adobe.com/flex/mx"
creationComplete="init()"
width="400" height="300"
>
<fx:Script>
<![CDATA[
private function init():void {
// how do I access the added components and place them where I want?
// do I use removeChildren and AddChildren?
// addItemsHere.addchild(nextButton);
]]>
</fx:Script>
<s:HGroup id='addItemsHere' />

Answer 1

As your component extends Group, you shall use addElement instead of addChild (and for all other methods with 'child' in their name it shall be replaced with 'element'. So, access to all elements will be like that:
for(var i:int =0; i < numElements; i++){
var button:Button = Button(getElementAt(i));
doWhatIWantWithMyButton(button);
}
It is also better to override createChildren method of your component if you know what to add at the creation moment.
If you don't need very specific button placement, you can set layout property of your component to any desired layout (like VerticalLayout, for example), and those layouts are tunable.

Answer 2

You seem to be trying to recreate functionality that already exists in the SDK. This is wat SkinnableContainer is for.
Depending on your use case, there are two ways to use it:
You only need to add some custom graphic elements to you custom component, but no additional behaviour
In this scenario, you would simple reuse SkinnableContainer and assign it a custom skin, like so:
<s:SkinnableContainer skinClass="MySkin">
<s:Button label='Button1' />
<s:Button label='Button2' />
</s:SkinnableContainer>
With MySkin.mxml perhaps something like:
<s:Skin xmlns:fx="http://ns.adobe.com/mxml/2009"
xmlns:s="library://ns.adobe.com/flex/spark">
<fx:Metadata>
[HostComponent("spark.components.SkinnableContainer")]
</fx:Metadata>
<s:states>
<s:State name="normal" />
<s:State name="disabled" />
</s:states>
<s:layout>
<s:VerticalLayout/>
</s:layout>
<s:Label text="I'm a SkinnableContainer"/>
<s:Group id="contentGroup" width="100%" height="100%">
</s:SkinnableContainer>
Your Buttons will now automatically be added to the contentGroup; the SkinnableContainer class handles this for you. Note that this Group must have exactly that id; it's a required SkinPart.
You want to add some behaviour to you component
The procedure is the same, but you would now subclass SkinnableContainer (this is usually done in pure ActionScript), write some behaviour in there, and assign the skin to an instance of this class.
public class MyComp extends SkinnableContainer {
//additional behaviour goes here
}
Usage:
<local:MyComp skinClass="MySkin">
<s:Button label='Button1' />
<s:Button label='Button2' />
</local:MyComp>