Re: Help with Undo and MVC
Re: Help with Undo and MVC
- Subject: Re: Help with Undo and MVC
- From: David Jeffery <email@hidden>
- Date: Thu, 6 Nov 2003 08:06:36 -0800
This is not the problem you are currently fighting, but you might also
want to fix this before you go any further:
- (NSUndoManager *)undoManager
{
return [self undoManager];
}
...because what you are doing is sending the "undoManager" message to
self (over and over and over and...). Your getter method should be
like this instead:
- (NSUndoManager *)undoManager
{
return undoManager;
}
David
On Monday, Nov 3, 2003, at 20:24 US/Pacific, Stephen Magyari wrote:
Thank you to Laurent and Drew for the responses, which helped me
clarify my
question --
How do I get my model to know that an NSUndoManager exists in my
document?
I think I need to either pass the undo manager "down" to the model or
have
the model keep a pointer "up" to the document, but I'm lost in either
case
in that I can't figure out exactly how to do it in a way that works.
Currently I have in my document's header:
- (NSUndoManager *)undoManager;
and in the implementation:
- (NSUndoManager *)undoManager {
return [self undoManager];
}
Is that correct? If not, how should I do it? If it is correct, then
what
should I do differently in the set method below (from my model's
implementation) to get it to recognize "undoManager" (which Xcode says
is
undeclared)?
- (void)setBookTitle:(NSString *)title;
{
[[undoManager prepareWithInvocationTarget:self]
setBookTitle:newBookTitle];
[newBookTitle release];
newBookTitle = title;
}
I've tried Drew's suggestion:
[[[doc undoManager] prepareWithInvocationTarget:self]];
But then Xcode says "doc" is undeclared, etc...
I'm clearly missing something or am doing something wrong and need a
nudge
(violent shove?) in the right direction. Thank you for the assistance
thus
far...
--Stephen
on 11/3/03 12:04 AM, Laurent Daudelin at email@hidden
wrote:
on 11/3/03 2:31 AM, Stephen Magyari at email@hidden wrote:
- (void)setBookTitle:(NSString *)title;
{
[[undoManager prepareWithInvocationTarget:self]
setBookTitle:newBookTitle];
[newBookTitle release];
newBookTitle = title;
}
I think the code above is correct (based on the examples I've seen)
but my
app won't compile (under Xcode), stating, "error: 'undoManager'
undeclared
(first use in this function....)"
Well, I think you should fix the first error you get before trying to
get
going with Undo/Redo. Did you declare that 'undoManager' variable? It
doesn't seem like you did in the method above. Is it because it's an
instance variable of the class that implements 'setBookTitle:'?
-Laurent.
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