如何使用Reactive Cocoa和通知

Question

如何从通知名称中创建信号？例如,我想从:

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

类似于:

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

Answer 1

-[NSNotificationCenter rac_addObserverForName:object:]返回无限信号.你可以像这样订阅它

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")
  }

该信号如无限所述.如果您需要此信号/订阅绑定到寿命self,您可以添加takeUntil:使用rac_willDeallocSignal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,您可以找到该NSNotificationCenter (RACSupport)类别.这有一个方法:

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