Hello again list,

I have a custom object class RSPerson with a handful of string properties. I 
have registered a singleton undoManager to observe changes, but the change dict 
is always coming up symmetrical. 

Edits made to the properties through UI do not appear in the change dict.
However setting the stringValue from the UI on the custom objects' properties 
does trigger the observer method (?!)

Some code. The observer is set on each person as the person is populated. 

RSPerson:

#import <Foundation/Foundation.h>
@interface RSPerson : NSObject

@property (strong) IBOutlet NSString * firstName;
@property (strong) IBOutlet NSString * lastName;
@property (strong) IBOutlet NSString * organization;

@property (strong) IBOutlet NSUndoManager * observer;

- (void) registerObserver:(id)observer;

@end

@implementation RSPerson

- (id) init {
    self = [super init];
    if(self) {

    }
    return self;
}

- (void) registerObserver:(id)observer {
    self.observer = observer;
    [self addObserver:observer forKeyPath:@"firstName"      
options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld) 
context:NULL];
    [self addObserver:observer forKeyPath:@"lastName"       
options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld) 
context:NULL];
    [self addObserver:observer forKeyPath:@"organization"   
options:(NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld) 
context:NULL];
}

- (void) dealloc {
    [self removeObserver:self.observer forKeyPath:@"firstName"];
    [self removeObserver:self.observer forKeyPath:@"lastName"];
    [self removeObserver:self.observer forKeyPath:@"organization"];
    self.observer = nil;
}

@end



RSUndoManager:

#import <Foundation/Foundation.h>
@interface RSUndoManager : NSUndoManager

+ (RSUndoManager *) sharedInstance;
+ (BOOL) sharedInstanceExists;

- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object 
change:(NSDictionary *)change context:(void *)context;

@end

@implementation RSUndoManager

static RSUndoManager * instance = nil;

+ (RSUndoManager *) sharedInstance {
    if(!instance ) {
        instance = [[[self class] alloc] init];
    }
    return instance;
}

+ (BOOL) sharedInstanceExists {
    return (nil != instance);
}

- (id) init {
    if(![[self class] sharedInstanceExists])
    {
        self = [super init];
        if(self) {
        }
        return self;
    }
    return instance;
}

- (void) observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object 
change:(NSDictionary *)change context:(void *)context
{
    NSLog(@" [%04d] %s %@: %@",__LINE__,__PRETTY_FUNCTION__, keyPath,[change 
description]);
    
    if([keyPath isEqualToString:@"organization"])
    {
        NSString * newVal = [change valueForKey:NSKeyValueChangeNewKey];
        NSString * oldVal = [change valueForKey:NSKeyValueChangeOldKey];
        if(newVal != oldVal) {
            NSLog(@" [%04d] %s %@: %@: %@",__LINE__,__PRETTY_FUNCTION__, @" not 
equal",oldVal,newVal);
        }
        else {
            NSLog(@" [%04d] %s %@: %@: %@",__LINE__,__PRETTY_FUNCTION__, @" is 
equal",oldVal,newVal);
        }
    }
}

@end


The case illustrated here ought to be showing me distinct values when I enter a 
value into my UI in the organization field. No such luck. 

Any suggestions?



Erik Stainsby
[email protected]


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