CODEWITHSUNDEEP
iosmethodsparameter-passingswift4
Hafiz Shoaib Awan
Hafiz Shoaib Awan

Reputation: 302

Swift Passing specific values in methods as arguments

How can I make method in which a user can pass only specific values for example 

button.setTitle("SKIP", for: .normal)

setTitle method takes specific parameters after "for", we just press . (dot) and it show suggestions for values to pass.

I want to do same thing, for example I want to make a method for calculate distance between 2 points,

func distanceBetween(loc1: CLLocation, and loc2: CLLocation, unit: String) -> CLLocationDistance {}

here user will pass location1 and location2 as arguments and I want to restrict user when he pass unit, he should have only 3 options, km, miles and meters.

Upvotes: 1

Views: 81

Answers (1)

Rakesha Shastri
Rakesha Shastri

Reputation: 11242

Create a enum with the values you need and use that enum as argument.

enum Unit {
     case km
     case miles
     case meters
}

Now your function would change to:

func distanceBetween(loc1: CLLocation, and loc2: CLLocation, unit: Unit) -> CLLocationDistance {
     switch unit {
     case .km:
         // Do something for kilometers
     case .miles:
         // Do something for miles
     case .meter:
         // Do something for meters
}

If in case you add a another unit, your compiler will throw an error saying that you haven't specified a default case and you would immediately be made to handle it.

And your fuction call would take any one of the Unit as argument. Example:

distanceBetween(loc1: location1, and loc2: location2, unit: .km)

Upvotes: 1

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