[Q] Making a button immune to mouse clicks
ned at bike-nomad.com
Sun Apr 14 14:23:20 UTC 2002
On Sunday 14 April 2002 07:08 am, I wrote:
> Any plain Morph (one that doesn't override handlesMouseDown: and
> mouseDown: et. al.) can be sensitized to mouse clicks. Just say:
> myMorph on: #mouseDown send: #doSomething to: someObject.
Just to clarify:
The #doSomething selector can actually have an arity (number of
arguments) of 0, 1, 2, or 3. So you can pass the event itself, the
morph that received the event, and a single parameter. But there is
only one parameter shared between all the event types. To pass a
parameter you use the form #on:send:to:withValue: .
These are passed as:
arity = 0 ifTrue:
[^ recipient perform: selector].
arity = 1 ifTrue:
[^ recipient perform: selector with: event].
arity = 2 ifTrue:
[^ recipient perform: selector with: event with: sourceMorph].
arity = 3 ifTrue:
[^ recipient perform: selector with: valueParameter with: event
Unfortunately, the error message in
EventHandler>>on:send:to:withValue: that says 'Warning: value
parameters are passed as last of 3 arguments' is incorrect, as is the
class comment in EventHandler which says it's:
mouseDownRecipient perform: mouseDownSelector3 with: event with:
targetMorph with: valueParameter
This is to keep you on your toes.
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