I'm pretty new to swift, trying to get authorization from user.

to request multiple auth at once, I gathered multiple options as array, and trying to request.

let variableArray = [UNAuthorizationOptions.badge, UNAuthorizationOptions.alert]
// error: Cannot convert value of type '[UNAuthorizationOptions]' to expected argument type 'UNAuthorizationOptions'
try! await UNUserNotificationCenter.current().requestAuthorization(options: variableArray)


//these works.        
try! await UNUserNotificationCenter.current().requestAuthorization(options: [.badge, .alert])
try! await UNUserNotificationCenter.current().requestAuthorization(options: .badge)

so I checked requestAuthorization, and found this:

open func requestAuthorization(options: UNAuthorizationOptions = []) async throws -> Bool

I think it takes both UNAuthorizationOptions and [UNAuthorizationOptions] but compiler says

"hey, you are trying to pass [UNAuthorizationOptions] but I need UNAuthorizationOptions!"

how can I append variableArray above code to requestAuthorization?

CodePudding user response：

This is because UNAuthorizationOptions conforms to the protocol OptionSet and an OptionSet can be initialised using an array literal, that is [...] which is something different than your variableArray which is an Array object.

So this is why you can do both

try! await UNUserNotificationCenter.current().requestAuthorization(options: [.badge, .alert])
try! await UNUserNotificationCenter.current().requestAuthorization(options: .badge)

because one takes an UNAuthorizationOptions and the other one an OptionSet of UNAuthorizationOptions

You will find that this is quite a common pattern in swift when passing options or similar to functions in UIKit, AppKit, Foundation etc

CodePudding user response：

You need to explicitly specify the type of your variableArray as UNAuthorizationOptions. Replace variableArray with:

let variableArray: UNAuthorizationOptions = [UNAuthorizationOptions.badge, UNAuthorizationOptions.alert]