Re: tearing my hair, ok here is a compilable example.
- Subject: Re: tearing my hair, ok here is a compilable example.
- From: Chris Idou <email@hidden>
- Date: Thu, 16 Oct 2008 01:54:43 -0700 (PDT)
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I disagree. I changed both to be NSObjects, and nothing changed.
--- On Thu, 10/16/08, Stephen J. Butler <email@hidden> wrote:
> From: Stephen J. Butler <email@hidden>
> Subject: Re: tearing my hair, ok here is a compilable example.
> To: email@hidden
> Date: Thursday, October 16, 2008, 12:03 AM
> It has something to do with Class1 being a subclass of
> NSObjectController. This code works for me with the same IB
> connections (sorry, had to reformat; it's my
> compulsion):
>
> #import <Cocoa/Cocoa.h>
>
> @interface Class1 : NSObject
> {
> BOOL canLink;
> }
>
> - (BOOL) canLink;
>
> - (IBAction) change:(id)v;
>
> @end
>
>
> #import "Class1.h"
>
> @implementation Class1
>
> - (BOOL) canLink
> {
> NSLog( @"%s %d nc:%p", _cmd, canLink, self );
> return canLink;
> }
>
>
> - (IBAction) change:(id)v
> {
> [self willChangeValueForKey:@"canLink"];
> canLink = !canLink;
> [self didChangeValueForKey:@"canLink"];
>
> NSLog( @"%s %d", _cmd, canLink );
> }
>
> - (void) setCanLink:(BOOL)aValue
> {
> canLink = aValue;
> }
>
> @end
>
>
> #import <Cocoa/Cocoa.h>
>
> @class Class1;
>
> @interface Class2 : NSObject
> {
> IBOutlet Class1 *class1;
> }
>
> - (BOOL) myMethod;
>
> @end
>
>
> #import "Class2.h"
> #import "Class1.h"
>
> @implementation Class2
>
> + (NSSet*) keyPathsForValuesAffectingMyMethod
> {
> NSLog( @"%s", _cmd );
> return [NSSet
> setWithObject:@"class1.canLink"];
> }
>
> #pragma mark -
>
> - (void) awakeFromNib
> {
> NSLog( @"%s class1:%p", _cmd, class1 );
>
> [self addObserver:self
> forKeyPath:@"myMethod"
> options:NSKeyValueObservingOptionNew
> context:[Class2 class]];
> }
>
> - (void) observeValueForKeyPath:(NSString*)keyPath
> ofObject:(id)object
> change:(NSDictionary*)change
> context:(void *)context
> {
> NSLog( @"%s %@", _cmd, keyPath );
> if (context == [Class2 class])
> {
> if ([keyPath
> isEqualToString:@"myMethod"])
> {
> NSLog( @"newvalue - myMethod:%d",
> [self myMethod] );
> }
> }
> else
> {
> [super observeValueForKeyPath:keyPath
> ofObject:object
> change:change context:context];
> }
> }
>
> - (BOOL) myMethod
> {
> return [class1 canLink];
> }
>
> @end
>
>
>
> On Thu, Oct 16, 2008 at 1:18 AM, Chris Idou
> <email@hidden> wrote:
> > That thought had occured to me, but making it
> readwrite doesn't seem to help. Cocoa NIB loading
> doesn't seem to call accessors, it seems to access them
> more directly. I even tried this:
> >
> >
> > -(Class1 *)class1 {
> > return class1;
> > }
> >
> > -(void)setClass1:(Class1 *)v {
> > NSLog(@"setClass1: %@", v);
> > [self
> willChangeValueForKey:@"class1"];
> > class1 = v;
> > [self
> didChangeValueForKey:@"class1"];
> > }
> >
> > But they don't get called.
> >
> > I even tried adding to awakeFromNIB:
> >
> > id old = [self class1];
> > [self setClass1:nil];
> > [self setClass1:old];
> >
> > To try and force the issue, but to no avail.
> >
> > Someone has observed that my code works when called
> from main() and bypassing IB. But it still doesn't work
> when loaded from a NIB!
> >
> >
> > --- On Wed, 10/15/08, Quincey Morris
> <email@hidden> wrote:
> >
> >> From: Quincey Morris
> <email@hidden>
> >> Subject: Re: tearing my hair, ok here is a
> compilable example.
> >> To: email@hidden
> >> Date: Wednesday, October 15, 2008, 10:54 PM
> >> On Oct 15, 2008, at 22:13, Chris Idou wrote:
> >>
> >> > @class Class1;
> >> > @interface Class2 : NSObject {
> >> > IBOutlet Class1 *class1;
> >> >
> >> >
> >> > }
> >> > @property(readonly) Class1 *class1;
> >> > -(BOOL)myMethod;
> >> > @end
> >> >
> >> > #import "Class2.h"
> >> > #import "Class1.h"
> >> >
> >> > @implementation Class2
> >> >
> >> > @synthesize class1;
> >> >
> >> > ...
> >> >
> >> > - (void)awakeFromNib {
> >> > [self addObserver:self
> >> > forKeyPath:@"myMethod"
> >> >
> options:NSKeyValueObservingOptionNew
> >> > context: [Class2 class]];
> >> >
> >> > }
> >> >
> >> >
> >> > + (NSSet *)keyPathsForValuesAffectingMyMethod
> {
> >> >
> >>
> NSLog(@"keyPathsForValuesAffectingMyMethod");
> >> > return [NSSet
> >> setWithObject:@"class1.canLink"];
> >> > }
> >>
> >> I think your problem is that Class2 isn't
> properly KVO
> >> compliant for
> >> the key "class1". Consider what happens
> when your
> >> nib is loaded. At
> >> some point, the nib loader needs to set
> "class1"
> >> to its correct value.
> >> Since the property is readonly and synthesized,
> there's
> >> no setter
> >> method, so the instance variable is changed
> directly.
> >> (I'm going from
> >> memory here, but I believe that's what
> documented to
> >> happen.) That
> >> presumably fails to trigger any KVO notifications,
> and your
> >>
> >> "keyPathsForValuesAffectingMyMethod" is
> not
> >> consulted.
> >>
> >> Try this:
> >>
> >> > ...
> >>
> >> > @interface Class2 ()
> >>
> >> > @property(readwrite) Class1 *class1;
> >> > @end
> >>
> >> >
> >>
> >> > @implementation Class2
> >> >
> >> > @synthesize class1;
> >> > ....
> >>
> >> If my theory is correct, that should cause the
> outlet to be
> >> set via a
> >> KVC-compliant setter, and the keypath dependency
> should
> >> start working.
> >>
> >>
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> >
> >
> >
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