Notifications and KVO observers used by AIM team

AIMNotificationObserver is a notification observer that should be used as alternative for [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(getNotification:) name:name object:sender]. AIMObserver is a KVO observer that should be used as an alternative for [obj addObserver:self forKeyPath:keyPath options:NSKeyValueObservingOptionNew|NSKeyValueObservingOptionOld|NSKeyValueObservingOptionInitial context:NULL];. It is guaranteed that observer is removed when the object is deallocated.

Usage

NSNotificationCenter observer:

@interface ViewController ()
@property (strong, nonatomic) AIMNotificationObserver *observer;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    __weak __typeof(self) weakSelf = self;
    self.observer = [AIMNotificationObserver observeName:@"changeBackground" onChange:^(NSNotification *notification) {
        //use weakSelf to avoid strong reference cycles
        weakSelf.view.backgroundColor = [UIColor red];
    }];
}

@end

KVO observer:

@interface ViewController ()
@property (strong, nonatomic) AIMObserver *observer;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    __weak __typeof(self) weakSelf = self;
    self.observer = [AIMObserver observed:self.view.layer keyPath:@"backgroundColor" onChange:^(NSDictionary *change) {
        //use weakSelf to avoid strong reference cycles
        [weakSelf.button setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
    }];
}

@end

Installation

Use the CocoaPods.

Add to your Podfile

pod 'AIMObservers'

and then call

pod install

and import

#import "AIMNotificationObserver.h"

or

#import "AIMObserver.h"

Example

In the example, AIMNotificationObserver is used to change the background of the main view, as respond to a notification and AIMObserver is used to change button text color, when background has changed (pretty lame usage, but in a real life application, you could use notification and KVO in a much more complicated way).