如何使用Reactive Cocoa和通知

如何从通知名称中创build一个信号？ 例如，我想从：

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(userDidChange:) name:kTTCurrentUserLoggedOffNotification object:nil]; 

像这样的东西：

 [signalForName(kTTCurrentUserLoggedOffNotification) subscribeNext:^(id x){ ... }]; 

Answer 1

-[NSNotificationCenter rac_addObserverForName:object:]返回一个无限信号。 你可以这样订阅

Objective-C的

 [[[[NSNotificationCenter defaultCenter] rac_addObserverForName:UIApplicationDidEnterBackgroundNotification object:nil] takeUntil:[self rac_willDeallocSignal]] subscribeNext:^(id x) { NSLog(@"Notification received"); }]; 

迅速

 NSNotificationCenter.defaultCenter() .rac_addObserverForName(UIKeyboardWillShowNotification, object: nil) .takeUntil(self.rac_willDeallocSignal()) .subscribeNext { (_) in print("Notification received") } 

---

这个信号是无限的。 如果你需要这个信号/订阅绑定到自己的生命周期，你可以添加takeUntil:与rac_willDeallocSignal是这样的：

Objective-C的

 [[[[NSNotificationCenter defaultCenter] rac_addObserverForName:UIApplicationDidEnterBackgroundNotification object:nil] takeUntil:[self rac_willDeallocSignal]] subscribeNext:^(id x) { NSLog(@"Notification received"); }]; 

迅速

 NSNotificationCenter.defaultCenter() .rac_addObserverForName(UIKeyboardWillShowNotification, object: nil) .takeUntil(self.rac_willDeallocSignal()) .subscribeNext { (_) in print("Notification received") } 

Answer 2

在RACExtensions中，您可以findNSNotificationCenter (RACSupport)类别。 这有一个方法来达到这个目的：

 - (RACSignal *)rac_addObserverForName:(NSString *)notificationName object:(id)object; 

Answer 3

使用ReactiveCocoa 4.1 Swift版本：

 NSNotificationCenter.defaultCenter() .rac_addObserverForName(UIKeyboardWillShowNotification, object: nil) .takeUntil(self.rac_willDeallocSignal()) .subscribeNext { (_) in print("UIKeyboardWillShowNotification") }