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MrFusion
Oct 28, 2009, 08:17 AM
I am breaking my head over KVO.

This is part of a NSArrayController subclass. I have to check when its selection changes and then do something with it.
Its parent class has the same code, but checks for arrangedObjects instead of selectedObjects.
The problem is that it works for arrangedObjects but not for selectedObjects. The documentation does say that selectedObjects adheres to KVO.

Any ideas as to the possible cause of this problem?


-(id) initWithCoder:(NSCoder *)decoder {
//init method for classes loaded from nib
self = [super initWithCoder:decoder];
if (self != nil) {
[self addObserver:self
forKeyPath:@"selectedObjects"
options:NSKeyValueObservingOptionNew
context:NULL]; //register for notification of new objects

}
return self;
}

#pragma mark -
#pragma mark cache
- (void)observeValueForKeyPath:(NSString *)keyPath
ofObject:(id)object
change:(NSDictionary *)change
context:(void *)context {
if ([keyPath isEqual:@"selectedObjects"]) { //selectedObjects
id selectedObject = [[self selectedObjects] myFirstObject];
// do something with selectedObject
}
// be sure to call the super implementation
// if the superclass implements it
[super observeValueForKeyPath:keyPath
ofObject:object
change:change
context:context];
}