Question

Why does Flash still offer to declare library items as either MovieClip, Graphic or Button? Is this just for backwards compatibility or is there any reason not to use MovieClip for everything? (Well, Button does have some additional functionality, but what about Graphic? does a Graphic have any advantage over a MovieClip?)

Answer 1

This tree might give you a good idea of what you’re asking:

Basically, the further up the tree you are, the more lightweight the object is going to be. As you can see, SimpleButton is going to be lighter and more suitable for situations where you only need the functionality of a click-able button with different states, rather than using MovieClip that can act as a container, have a timeline, etc etc.

It’s good practice to try and aim for the use of the most primitive types possible. For example, if you’re not going to have timeline animation for a graphic, use Sprite. If ontop of that you’re not going to be adding anything additional into the graphic, use Shape, and so on.

Something major to note is that MovieClip is the heaviest DisplayObject you can use.