Retrieving the information in the `change` dictionary from KVO

cocoa, key-value-observing, objective-c

Solution

Here's a list of the keys used by the change dictionary.

An extract:

Keys used by the change dictionary

These constants are used as keys in the change dictionary passed to `observeValueForKeyPath:ofObject:change:context:`.

NSString *const NSKeyValueChangeKindKey;
NSString *const NSKeyValueChangeNewKey;
NSString *const NSKeyValueChangeOldKey;
NSString *const NSKeyValueChangeIndexesKey;
NSString *const NSKeyValueChangeNotificationIsPriorKey;

Problem

The method ``` - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context { } ``` has a parameter `change` which is a dictionary that contains information about the nature of the value change, how would I find out what was in this dictionary?

Original source