# NSKeyValueObserving documentation

2005 Free Software Foundation, Inc.
Software documentation for the NSArray(NSKeyValueObserverRegistration) category
Foundation/NSKeyValueObserving.h
NSArray objects are not observable, so the registration methods raise an exception.
addObserver:
anObserver
toObjectsAtIndexes:
indexes
forKeyPath:
aPath
options:
options
context:
aContext
Description forthcoming.
removeObserver:
anObserver
fromObjectsAtIndexes:
indexes
forKeyPath:
aPath
Description forthcoming.
Software documentation for the NSObject(NSKeyValueObserverNotification) category
Foundation/NSKeyValueObserving.h
These methods are sent to the receiver when observing it active for a key and the key is about to be (or has just been) changed.
didChange:
changeKind
valuesAtIndexes:
indexes
forKey:
aKey
Description forthcoming.
didChangeValueForKey:
aKey
Description forthcoming.
didChangeValueForKey:
aKey
withSetMutation:
mutationKind
usingObjects:
objects
Description forthcoming.
willChange:
changeKind
valuesAtIndexes:
indexes
forKey:
aKey
Description forthcoming.
willChangeValueForKey:
aKey
Description forthcoming.
willChangeValueForKey:
aKey
withSetMutation:
mutationKind
usingObjects:
objects
Description forthcoming.
Software documentation for the NSObject(NSKeyValueObserverRegistration) category
Foundation/NSKeyValueObserving.h
Description forthcoming.
addObserver:
anObserver
forKeyPath:
aPath
options:
options
context:
aContext
Description forthcoming.
removeObserver:
anObserver
forKeyPath:
aPath
Description forthcoming.
Software documentation for the NSObject(NSKeyValueObserving) category
Foundation/NSKeyValueObserving.h
Description forthcoming.
observeValueForKeyPath:
aPath
ofObject:
anObject
change:
aChange
context:
aContext
Description forthcoming.
Software documentation for the NSObject(NSKeyValueObservingCustomization) category
Foundation/NSKeyValueObserving.h
These methods permit modifications to the observing system.
automaticallyNotifiesObserversForKey:
aKey
Specifies whether the class should send the notification methods of the NSKeyValueObserverNotification protocol when instances of the class receive messages to change the value for the key.
The default implementation returns `YES`.
keyPathsForValuesAffectingValueForKey:
dependentKey
Returns a set of key paths for properties whose values affect the value of the specified dependentKey.
setKeys:
triggerKeys
triggerChangeNotificationsForDependentKey:
dependentKey
Tells the observing system that when NSKeyValueObserverNotification protocol messages are sent for any key in the triggerKeys array, they should also be sent for dependentKey.
observationInfo
Returns a reference to the observation information for the receiver as stored using the -setObservationInfo: method.
The default implementation returns information from a global table.
setObservationInfo:
observationInfo
Stores observation information for the receiver. By default this is done in a global table, but classes may implement storage in an instance variable or some other scheme (for improved performance).