如何获得低于 iOS 11.2 的应用内购买订阅期？

Question

I am new on in-app purchase. How can I get subscriptionPeriod below iOS 11.2? As I see it is available from iOS 11.2 in SKProduct class. My code is like this:

var durationNumberString: String? {
    if #available(iOS 11.2, *) {
        guard let nu = product.subscriptionPeriod?.numberOfUnits else { return nil }
        return "\(nu)"
    } else {
        return nil
    }
}

var durationUnitString: String? {
    if #available(iOS 11.2, *) {
        guard let unit = product.subscriptionPeriod?.unit else { return nil }
        
        switch unit {
        case .day:
            return "day"
        case .week:
            return "weak"
        case .month:
            return "month"
        case .year:
            return "year"
        @unknown default:
            return ""
        }
    } else {
        return nil
    }
}

I want to give durationNumberString and durationUnitString values below iOS 11.2 also.

Answer 1

I have found the solution. Before iOS 11.2 I can get durationNumberString and durationUnitString by hardcoding, using product identifier.

var durationNumberString: String? {
    if #available(iOS 11.2, *) {
        guard let nu = product.subscriptionPeriod?.numberOfUnits else { return nil }
        return "\(nu)"
    } else {
        switch product.productIdentifier {
        case "id_199_month":
            return "1"
        case "id_499_3month":
            return "3"
        case "id_2099_annual":
            return "1"
        default:
            return nil
        }
    }
}

var durationUnitString: String? {
    if #available(iOS 11.2, *) {
        guard let unit = product.subscriptionPeriod?.unit else { return nil }
        
        switch unit {
        case .day:
            return "day"
        case .week:
            return "weak"
        case .month:
            return "month"
        case .year:
            return "year"
        @unknown default:
            return ""
        }
    } else {
        switch product.productIdentifier {
        case "id_499_3month",
             "id_199_month":
            return "month"
        case "id_2099_annual":
            return "year"
        default:
            return nil
        }
    }
}