Adding and Removing Observer in UIView

ref – http://stackoverflow.com/questions/8200775/when-to-unsubscribe-from-a-nsnotification-in-a-uiview

In your UIView custom class:

- (void)didMoveToWindow {

if (self.window) {

NSLog(@"Added to a window, similar to -viewDidLoad.");

// Subscribe to notifications here.

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(topicAndEntry:)

name:INSERT_TOPIC_ENTRY

object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self

selector:@selector(topicAndEntry:)

name:INSERT_REQUIRED_KEY_VALUE

object:nil];

}

- (void)willMoveToWindow:(UIWindow *)newWindow {

if (newWindow == nil) {

NSLog(@"Will be removed from window, similar to -viewDidUnload.");

// Unsubscribe from any notifications here.

[[NSNotificationCenter defaultCenter] removeObserver:self

name:INSERT_TOPIC_ENTRY

object:nil];

[[NSNotificationCenter defaultCenter] removeObserver:self

name:INSERT_REQUIRED_KEY_VALUE

object:nil];

}