> Message: 1
> Date: Sun, 20 Apr 2008 14:02:52 -0600
> From: Keary Suska <[EMAIL PROTECTED]>
> Subject: Re: Binding NSButton enabled state
> To: "Cocoa-Dev (Apple)" <cocoa-dev@lists.apple.com>
> Message-ID: <[EMAIL PROTECTED]<[EMAIL PROTECTED]>
> >
> Content-Type: text/plain; charset="US-ASCII"
>
> on 4/20/08 11:47 AM, [EMAIL PROTECTED] purportedly said:
>
> > On Sat, Apr 19, 2008 at 11:55 PM, Chris Hanson <[EMAIL PROTECTED]> wrote:
> >
> >> On Apr 19, 2008, at 11:08 AM, Lorenzo Thurman wrote:
> >>
> >> I have two NSTableViews, tableA and tableB, each managed by separate
> >>> NSArrayControllers. When a selection is made in either table, an
> >>> instance
> >>> variable is set. I want to have an NSButton's enabled state to 'YES'
> >>> whenever the instance variable is set.
> >>>
> >>
> >> Don't think of it as an instance variable, think of it as a property.
> >> Restating your problem, you want your "Do Something" button's enabled
> >> property to be bound to your window controller's "can do something"
> >> property.
> >>
> >> What this means is that you need to manipulate your window controller's
> >> "can do something" property in a way that things bound to it can notice
> --
> >> in other words, in a way that will post key-value observing
> notifications.
> >> Thus instead of manipulating it as an instance variable, you should
> just
> >> always invoke its setter.
> >>
> >> You haven't said how you're actually noticing that the selection in one
> of
> >> your tables has changed; I assume you're either using an NSTableView
> >> delegate method or a notification to do so.
> >>
> >> -- Chris
> >>
> >>
> > Here's my code:I register to receive these notifications when the
> selection
> > changes.
> >
> > -(void)applicationDidFinishLaunching:(NSNotification*)not{
> >
> >
> > [[NSNotificationCenter defaultCenter] addObserver:self
> selector:@selector(
> > usTableViewSelectionDidChange:) name:
> > NSTableViewSelectionDidChangeNotification object:usCityTable];
> >
> > [[NSNotificationCenter defaultCenter] addObserver:self
> selector:@selector(
> > intlableViewSelectionDidChange:) name:
> > NSTableViewSelectionDidChangeNotification object:intlTable];
> >
> > }
> >
> >
> > These are the messages sent when a selection is changed (Is there a way
> to
> > use just one?):
>
> Yes, if instead you make your controlling object the delegate to both
> tableviews and implement -tableViewSelectionDidChange:.
>
> > -(void) usTableViewSelectionDidChange:(NSNotification*)not{
> >
> > NSArray* selObjs = [usTableContent selectedObjects];
> >
> > if([selObjs count] > 0) {
> >
> > [intlTable deselectAll:self];
> >
> > NSDictionary* selectedDictionary = [selObjs objectAtIndex:0];
> >
> > [self setValue:[selectedDictionary objectForKey:@"location"] forKey:
> > @"location"];
> >
> > [self setSelectedItem:selectedDictionary];
> >
> > }
> >
> > }
> >
> > -(void) intlableViewSelectionDidChange:(NSNotification*)not{
> >
> > NSArray* selObjs = [intlTableContent selectedObjects];
> >
> > if([selObjs count] > 0){
> >
> > [cityTable deselectAll:self];
> >
> > NSDictionary* selectedDictionary = [selObjs objectAtIndex:0];
> >
> > [self setValue:[selectedDictionary objectForKey:@"location"] forKey:
> > @"location"];
> >
> > [self setSelectedItem:selectedDictionary];
> >
> > }
> >
> >
> > }
>
> Note that when you call -deselectAll:, that triggers an
> NSTableViewSelectionDidChangeNotification, so you may want to watch out.
> Your checks probably avoid loops, but the notifications will get sent more
> often than is necessary.
>
> Anyway, what kind of object is "location"? Are you applying any
> transformers? If not, how are you considering how your object will get
> coerced into a boolean?
>
> HTH,
>
> Keary Suska
> Esoteritech, Inc.
> "Demystifying technology for your home or business"
>
>
>
>
> I'll look at the tableview deleegates again. I looked at those before, but
reasoned that they might not work as I would like, but I can't remember why.
Thanks for pointing out the potential for looping and the extra
notifications that get sent, but the problem I ran into without the
deselectAll, was that if I made a selection in tableA, my interface updated
correctly, then made a selection in tableB, my interface updated correctly,
but then made the same selection again in tableA, my interface did not
update correctly, since there was not change in selection
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