Implementing a singleton approach in Swift

Before you write Swift's Singleton method, you can review the objective-c of the single example:

 1  + (Instancetype) sharedsingleton{  2  static  id   instance;  3   Static   dispatch_once_t Oncetoken;  5  dispatch_once (&oncetoken, ^{ Span style= "color: #008080;" >6  instance = [[Self alloc] init];  7  });  8  return   instance;  9 } 

The first thing to consider is to follow the notation in OC to write one.

So one way to do this in Swift is as follows:

1 classSingleton:nsobject {2 3     Staticvar Instance:singleton?4     Staticvar oncetoken:dispatch_once_t =05     6     //Follow the notation in OC7     classFunc Sharedsingleton ()Singleton {8Dispatch_once_ (&oncetoken) {() Voidinch9Instance =Singleton ()Ten      One         } A         returninstance! -     } -}

Swift has done a lot of optimization on the OC Foundation, so consider using some of the new features of Swift to implement the singleton.

Given that the let in Swift itself is thread-safe, implementing a singleton in Swift can be very concise:

static Let Sharedsingleton = Singleton ()

Since the implementation has changed from the original function to a property, so the use of the corresponding adjustments need to be made, when used as follows:

Singleton.sharedsingleton

Thus, Swift, which has been optimized to absorb the advantages of multiple languages, has been largely streamlined compared to the previous one.

Implementing a singleton approach in Swift