如何在通知中使用反应式Cocoa

How can I create a signal out of a notification name? For example, I want to go from:

如何用通知名创建信号?例如，我想从

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

to something like:

类似的:

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

3 个解决方案

#1

-[NSNotificationCenter rac_addObserverForName:object:] returns an infinite signal. You can subscribe to it like this

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

Objective-c

objective - c

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

Swift

斯威夫特

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

---

This signal is as stated infinite. If you need this signal/subscription to be bound to the lifetime of self you can add takeUntil: with rac_willDeallocSignal like this:

这个信号是无限的。如果需要将此信号/订阅绑定到self的生命周期，可以添加takeUntil:与rac_willDeallocSignal如下:

Objective-c

objective - c

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

Swift

斯威夫特

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

#2

In the RACExtensions you can find the NSNotificationCenter (RACSupport) category. That has a method for this purpose:

在RACExtensions中，可以找到NSNotificationCenter (RACSupport)类别。为此目的有一种方法:

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

#3

Swift version using ReactiveCocoa 4.1:

使用ReactiveCocoa的Swift版本4.1:

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