Use custom AS Class in MXML

Question

Hi,
I have a custom class which extend button, and parameters is
needed in constructor.
when I try to put the class in MXML as visual compoents such
as <mx:customButton />
ArgumentError: Error #1063: Argument count mismatch on ____
Expected 0, got 1.
Appearently the parameters for the constructor is missed. but
how can i pass the parameters in the tag?
Thanks in advances.
C.

Answer 1

You can't use arguments on the constructor in MXML. Aside of
anything else, there's no way to pass them. Your options are - if
you want to use the same component from AS and really want those
constructor arguments, is to make them optional:
public customButton(myArg:String=null)...
The attributes specified in the MXML will be assigned to
public properties by the same name once the instance has been
created. So if you want to be able to say:
<mx:customButton myArg="hello"/>
You'll need to do something like:
public class customButton extends Button{
public var myArg:String;
By the way it's conventional to use uppercase to start the
name of a class, and lowercase to start the name of an instance. So
it would be conventional to call your class CustomButton.
Tim