Re: [platform-swt-dev] Composite Obsession

[Steve Northover <Steve_Northover@xxxxxxxxxx>]

Tree and Table are Composites because
they can have Control children, for example, cell editors that are Text
controls.  Combo is a Composite mainly for historical reasons.  On
platforms that don't have a native Combo (or Spinner), the control needs
to be emulated by a Text and a List or some other control.  Due to
Java strong typing, only Composites can have children so an emulated Combo
must be a subclass of Composite.  The SWT class hierarchy must be
identical across platforms for portablity.  Hence, Combo and Spinner
are subclasses of Composite.  Sorry.

"Ivan Markov" <ivan.markov@xxxxxxxxx>
Sent by: platform-swt-dev-admin@xxxxxxxxxxx

11/24/2004 02:33 PM

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Subject	[platform-swt-dev] Composite Obsession

Hey,
 
Yesterday I started porting the new Spinner
widget to SWT/Fox and oh, horror! The everything-is-composite saga continues!
Why is this widget Composite? Does it make
sense for it to have children?
 
Also, why are Tree & Table Composite
and List only Scrollable?
In fact, why other controls besides Canvas,
Decorations & Shell inherit from Composite?
 
-Ivan