How do you create custom notifications in Swift 3?

Question

In Objective-C, a custom notification is just a plain NSString, but it\'s not obvious in the WWDC version of Swift 3 just what it should be.

Answer 1

If you want this to work cleanly in a project that uses both Objective-C and Swift at the same time, I found it to be easier to create the notifications in Objective-C.

Create an .m/.h file:

//CustomNotifications.h
#import 

// Add all notifications here
extern const NSNotificationName yourNotificationName;

//CustomNotifications.m
#import "CustomNotifications.h"

// Add their string values here
const NSNotificationName yourNotificationName = @"your_notification_as_string";

In your MyProject-Bridging-Header.h (named after your project) to expose them to Swift.

#import "CustomNotifications.h"

Use your notifications in Objective-C like this:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(yourMethod:) name:yourNotificationName:nil];

And in Swift (5) like this:

NotificationCenter.default.addObserver(self, selector: #selector(yourMethod(sender:)), name: .yourNotificationName, object: nil)