I seem to have found a reasonable solution, but I'm a bit confused about why it
works and other things haven't.
To recap, I'm trying to control an array of dictionaries. Each dictionary
contains a file name and a checkbox (boolean). The array is stored in a
@"files" member of the user defaults.
Firstly, it seems that checking "handles content as compound value" for the
array controller seems to help, because any change (even just the checkbox)
then triggers a full update to the model, and I can get notified that the top
level array has changed.
Now if I bind my NSArrayController to my NSPreferencesController subclass, with
Controller key = "values" and key path = "files", it notifies on any update,
including just the checkbox. However it doesn't accept external changes to the
user preferences. If I change and set the "files" attribute of the User
Defaults, it doesn't update.
BUT...
if I kind of proxy the values, and have this in my preferences controller:
-(NSArray *)files {
return [[[self values] valueForKey:@"files"] makeCollectionMutable];
}
-(void)setFiles:(NSArray *)files {
[[self values] setValue:files forKey:@"files"];
}
and I have an observer for the user defaults:
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context {
if ([keyPath isEqualToString:@"files"]) {
[self didChangeValueForKey:@"files"];
}
}
Now instead I link my NSArray Controller to Controller key = "files" and key
path = "" (blank), now it seems to work fine bi-directionally.
Which is good, but I don't understand why it should work differently to just
having Controller key = "values" and key path = "files".
It seems like the way the bindings work is it is listening to changes to
"values" but not changes to "values.files". It seems like what I need is
Controller key = "values.files" and key path = "" (blank). But IB doesn't seem
to allow the controller key to be a dotted value.
Am I thinking about this wrong somehow? Can I get the bindings to listen to
changes to values.files without having to proxy it through my own methods?
--- On Thu, 9/18/08, Chris Idou <[EMAIL PROTECTED]> wrote:
> From: Chris Idou <[EMAIL PROTECTED]>
> Subject: Re: Listening for changes in a table
> To: cocoa-dev@lists.apple.com
> Date: Thursday, September 18, 2008, 8:27 PM
> --- On Thu, 9/18/08, Ken Thomases
> <[EMAIL PROTECTED]> wrote:
>
> > Two possibilities:
> >
> > * If you used a custom class rather than a dictionary,
> then
> > there
> > would be a setter of your own design called when the
> > property is set
> > due to a change in the checkbox.
>
> Yes I could do that, but given that I'm storing the
> result in the user preferences, and the user preferences can
> store dictionaries but not objects, I was hoping to stay
> with dictionaries.
>
> Maybe I should try inheriting from NSMutableDictionary or
> something.
>
> > * Your controller can use KVO to observe the property
> to
> > which the
> > checkbox is bound. Then it will receive change
> > notifications when the
> > property is changed.
>
> Would that mean observing every single dictionary in the
> array and adding and removing observers as the array expands
> and contracts? Sounds fiddly.
>
> --- On Thu, 9/18/08, I. Savant
> <[EMAIL PROTECTED]> wrote:
>
> > Why does everybody forget about / ignore
> > <NSTableDataSource>?
>
> I'm a bit vague on how a DataSource and an
> ArrayController work together. Do you choose one or the
> other? In any case, it sounds like a fairly fiddly option
> too.
>
>
>
>
>
>
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