CODEWITHSUNDEEP
objective-cswiftapi-design
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Reputation: 958

Objective-C API: Can an NSNumber become an Int in Swift?

I am writing a framework in Objective-C, and the goal is it should be a joy to use in Swift as well.

One of my properties is a nullable NSNumber. Is there any way to bridge this to an optional Int when the API is used in Swift?

Upvotes: 0

Views: 1178

Answers (1)

Fujia
Fujia

Reputation: 1242

As per the documentation:

Swift automatically bridges certain native number types, such as Int and Float, to NSNumber.

It also allows you to pass a value of type Int, for example, to an argument expecting an NSNumber. Note that because NSNumber can contain a variety of different types, you cannot pass it to something expecting an Int value.

All of the following types are automatically bridged to NSNumber:

  • Int
  • UInt
  • Float
  • Double
  • Bool

So you can safely use these scalar types in swift and cast them to NSNumber in objc, but not the other way around. NSNumber may represent a float value, and you will see an error if you cast it to Int in swift.

Upvotes: 1

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