Paul Dupuis wrote:
> For desktop applications on Windows and OSX, I am lookingf or what
> people consider the best practice to be for enabling, disabling, or
> updating menu items based on context.
>
> You have so many ways in the LiveCode language to do this:
>
> enable menuItem 2 of menu "Edit"
> disable menuItem 3 or menu "File"
>
> get the text of btn "Edit"
> if first char of line 3 of it is "(" then delete first char of line 3
> of it -- enables 3 menuItem in Edit menu
> set the text of btn "Edit" to it
>
> enable menuitem 2 of btn "File" of grp "Menubar" -- Enable Open
>
> and probably a number of other syntax variations I have forgotten. So
> is there one of the many syntax variations for menus that is "Best"
> (i.e most reliable, best performance, best balance between
> reliability and performance)
IIRC the "menu" keyword will favor whatever's in the default menu bar,
which may or may not be ideal depending on your circumstance.
For example, if you script:
disable menuitem 2 of menu "File"
...if the topmost stack has a File menu, or you have a custom menu stack
being used as a menu bar and the defaultMenubar points to it, you may
get what you expect.
But if you're not quite so careful you may wind up disabling something
in the LC IDE menubar while it's set to the defaultMenubar.
Also, IIRC the "menuItem" keyword is useful only for enabling and
disabling menu items, but I don't believe it can be used for setting
checkmarks, mnemonics, or other options.
Given that the "menu" reference is finicky and "menuItem" limited, I
rarely use either.
Working with the menuitems as text give me complete control and
unambiguous object references, for the small price of a little extra typing.
I was curious about performance, so I ran the test copied below, with
these results:
MenuItem: 219 ms
As text: 10 ms
The difference may not be surprising given that the menuItems are a
single property (rather than separately stored elements for each item as
with SuperCard), so it seems the engine needs to get all the items for a
menu, manipulate the ones in question, and restore them to the menu
object each time a change is made to any one of them.
Those results were in v9.
Interestingly, v6 seems much slower (thanks team for the speed bump with
menu updating):
MenuItem: 3473 ms
As text: 131 ms
-----------------------------------------------------------------------
-- Test script
-- Compare speed of disabling all even-numbered items in a menu
-- containing 100 items.
-- Requires 1 pulldown menu named "m1"
on mouseUp
-- Setup menu:
repeat with i = 1 to 100
put "item "& i &cr after s
end repeat
delete last char of s -- trailing CR
put s into btn "m1"
--
-- Params for test:
put 10 into n
put the text of btn "m1" into s
--
-- Test 1: menuItem
put the millisecs into t
repeat n
put s into btn "m1"
SetMenu1
end repeat
put the millisecs - t into t1
put the text of btn 1 into r1
--
-- Test 2: text
put the millisecs into t
repeat n
put s into btn "m1"
SetMenu2
end repeat
put the millisecs - t into t2
put the text of btn 1 into r2
--
-- Display results:
put "MenuItem: "& t1 &" ms" &cr \
& "As text: "& t2 &" ms" &cr \
& "Match?: "& (r1 is r2)
end mouseUp
on SetMenu1
repeat with i = 2 to the number of lines of the text of btn "m1" step 2
disable menuitem i of btn "m1"
end repeat
end SetMenu1
on SetMenu2
put the text of btn 1 into s
put 0 into i
put empty into tNuS
repeat for each line tLine in s
add 1 to i
if i mod 2 = 0 then
put "("& tLine &cr after tNuS
else
put tLine &cr after tNuS
end if
end repeat
delete last char of tNuS
set the text of btn "m1" to tNuS
end SetMenu2
--
Richard Gaskin
Fourth World Systems
Software Design and Development for the Desktop, Mobile, and the Web
____________________________________________________________________
ambassa...@fourthworld.com http://www.FourthWorld.com
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