文章标题

[a addObserver:b forKeyPath:@”name” options:NSKeyValueObservingOptionOld | NSKeyValueObservingOptionNew context:@”test”];

-(void)observeValueForKeyPath:(NSString )keyPath ofObject:(id)object change:(NSDictionary )change context:(void *)context
{
NSLog(@”%@ %@ %@ %@”, object, keyPath, change, context);
}