Instance Method

addObserver:forKeyPath:options:context:

Raises an exception.

Declaration

- (void)addObserver:(NSObject *)observer forKeyPath:(NSString *)keyPath options:(NSKeyValueObservingOptions)options context:(void *)context;

Parameters

observer

The object to register for KVO notifications. The observer must implement the key-value observing method observeValueForKeyPath:ofObject:change:context:.

keyPath

The key path, relative to the array, of the property to observe. This value must not be nil.

options

A combination of NSKeyValueObservingOptions values that specifies what is included in observation notifications.

context

Arbitrary data that is passed to observer in observeValueForKeyPath:ofObject:change:context:.

Discussion

NSArray objects are not observable, so this method raises an exception when invoked on an NSArray object. Instead of observing an array, observe the to-many relationship for which the array is the collection of related objects.

See Also

Key-Value Observing

- removeObserver:forKeyPath:

Raises an exception.

- addObserver:toObjectsAtIndexes:forKeyPath:options:context:

Registers an observer to receive key value observer notifications for the specified key-path relative to the objects at the indexes.

- removeObserver:fromObjectsAtIndexes:forKeyPath:

Removes anObserver from all key value observer notifications associated with the specified keyPath relative to the array’s objects at indexes.