大家好，我叫Vitaly，是Adapty的创始人。我们将继续讨论专门针对iOS应用程序内购买的系列文章。在上一部分中，我们介绍了创建和配置应用内购买的过程。在本文中，我们将分析最简单的付款墙（付款屏幕）的创建，以及我们在第一阶段配置的购买的初始化和处理。

创建订阅屏幕

任何使用应用程序内购买的应用程序都具有付费专区。有要求苹果定义的最小集合所需的元素和说明性文本这种屏幕。在这个阶段，我们将不会尽可能准确地执行所有操作，但是我们的版本将非常接近工作版本。

因此，我们的屏幕将包含以下功能元素：

标题：解释性/销售块。
一组用于启动购买过程的按钮。它们还将显示订阅的主要属性：以当地货币（商店的货币）显示的名称和价格。
恢复过去的购买按钮。使用订阅或非消耗性购买的所有应用程序都需要此元素。

Interface Builder Storyboard. ViewController, UI (UIActivityIndicatorView) , .

ViewController. , .

import StoreKit
import UIKit

class ViewController: UIViewController {

    // 1:
    @IBOutlet private weak var purchaseButtonA: UIButton!
    @IBOutlet private weak var purchaseButtonB: UIButton!
    @IBOutlet private weak var activityIndicator: UIActivityIndicatorView!

    override func viewDidLoad() {
        super.viewDidLoad()
        activityIndicator.hidesWhenStopped = true

        // 2:
        showSpinner()
        Purchases.default.initialize { [weak self] result in
            guard let self = self else { return }
            self.hideSpinner()

            switch result {
            case let .success(products):
                DispatchQueue.main.async {
                    self.updateInterface(products: products)
                }
            default:
                break
            }
        }
    }

    // 3:
    private func updateInterface(products: [SKProduct]) {
        updateButton(purchaseButtonA, with: products[0])
        updateButton(purchaseButtonB, with: products[1])
    }

    // 4:
    @IBAction func purchaseAPressed(_ sender: UIButton) { }

    @IBAction func purchaseBPressed(_ sender: UIButton) { }

        @IBAction func restorePressed(_ sender: UIButton) { }
}

- UI
viewDidLoad . , , UI, . , — . -, .
, , , .
- .

extension ViewController {
    // 1:
    func updateButton(_ button: UIButton, with product: SKProduct) {
        let title = "\(product.title ?? product.productIdentifier) for \(product.localizedPrice)"
        button.setTitle(title, for: .normal)
    }

    func showSpinner() {
        DispatchQueue.main.async {
            self.activityIndicator.startAnimating()
            self.activityIndicator.isHidden = false
        }
    }

    func hideSpinner() {
        DispatchQueue.main.async {
            self.activityIndicator.stopAnimating()
        }
    }
}Spinner

, (1) SKProduct. , extension :

extension SKProduct {
    var localizedPrice: String {
        let formatter = NumberFormatter()
        formatter.numberStyle = .currency
        formatter.locale = priceLocale
        return formatter.string(from: price)!
    }

    var title: String? {
        switch productIdentifier {
        case "barcode_month_subscription":
            return "Monthly Subscription"
        case "barcode_year_subscription":
            return "Annual Subscription"
        default:
            return nil
        }
    }
}

Purchases

. Apple. Purchases , , SKProduct .

typealias RequestProductsResult = Result<[SKProduct], Error>
typealias PurchaseProductResult = Result<Bool, Error>

typealias RequestProductsCompletion = (RequestProductsResult) -> Void
typealias PurchaseProductCompletion = (PurchaseProductResult) -> Void

class Purchases: NSObject {
    static let `default` = Purchases()

    private let productIdentifiers = Set<String>(
        arrayLiteral: "barcode_month_subscription", "barcode_year_subscription"
    )

    private var products: [String: SKProduct]?
    private var productRequest: SKProductsRequest?

    func initialize(completion: @escaping RequestProductsCompletion) {
        requestProducts(completion: completion)
    }

    private var productsRequestCallbacks = [RequestProductsCompletion]()

    private func requestProducts(completion: @escaping RequestProductsCompletion) {
        guard productsRequestCallbacks.isEmpty else {
            productsRequestCallbacks.append(completion)
            return
        }

        productsRequestCallbacks.append(completion)

        let productRequest = SKProductsRequest(productIdentifiers: productIdentifiers)
        productRequest.delegate = self
        productRequest.start()

        self.productRequest = productRequest
    }
}

Delegate:

extension Purchases: SKProductsRequestDelegate {
        guard !response.products.isEmpty else {
            print("Found 0 products")

            productsRequestCallbacks.forEach { $0(.success(response.products)) }
            productsRequestCallbacks.removeAll()
            return
        }

        var products = [String: SKProduct]()
        for skProduct in response.products {
            print("Found product: \(skProduct.productIdentifier)")
            products[skProduct.productIdentifier] = skProduct
        }

        self.products = products

        productsRequestCallbacks.forEach { $0(.success(response.products)) }
        productsRequestCallbacks.removeAll()
    }

    func request(_ request: SKRequest, didFailWithError error: Error) {
        print("Failed to load products with error:\n \(error)")

        productsRequestCallbacks.forEach { $0(.failure(error)) }
        productsRequestCallbacks.removeAll()
    }
}

, , , enum PurchaseError, Error ( LocalizedError):

enum PurchasesError: Error {
    case purchaseInProgress
    case productNotFound
    case unknown
}

StoreKit, ( ).

purchaseProduct , restorePurchases — ( non-consumable ):

        fileprivate var productPurchaseCallback: ((PurchaseProductResult) -> Void)?

    func purchaseProduct(productId: String, completion: @escaping (PurchaseProductResult) -> Void) {
        // 1:
        guard productPurchaseCallback == nil else {
            completion(.failure(PurchasesError.purchaseInProgress))
            return
        }
        // 2:
        guard let product = products?[productId] else {
            completion(.failure(PurchasesError.productNotFound))
            return
        }

        productPurchaseCallback = completion

        // 3:
        let payment = SKPayment(product: product)
        SKPaymentQueue.default().add(payment)
    }

    public func restorePurchases(completion: @escaping (PurchaseProductResult) -> Void) {
        guard productPurchaseCallback == nil else {
            completion(.failure(PurchasesError.purchaseInProgress))
            return
        }
        productPurchaseCallback = completion
        // 4:
        SKPaymentQueue.default().restoreCompletedTransactions()
    }

, ( , , , , )
peoductId,
SKPaymentQueue
, SKPaymentQueue

, , SKPaymentTransactionObserver:

extension Purchases: SKPaymentTransactionObserver {
    func paymentQueue(_ queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) {
        // 1:
        for transaction in transactions {
            switch transaction.transactionState {
            // 2:
            case .purchased, .restored:
                if finishTransaction(transaction) {
                    SKPaymentQueue.default().finishTransaction(transaction)
                    productPurchaseCallback?(.success(true))
                } else {
                    productPurchaseCallback?(.failure(PurchasesError.unknown))
                }
            // 3:
            case .failed:
                productPurchaseCallback?(.failure(transaction.error ?? PurchasesError.unknown))
                SKPaymentQueue.default().finishTransaction(transaction)
            default:
                break
            }
        }

                productPurchaseCallback = nil
    }
}

extension Purchases {
    // 4:
    func finishTransaction(_ transaction: SKPaymentTransaction) -> Bool {
        let productId = transaction.payment.productIdentifier
        print("Product \(productId) successfully purchased")
        return true
    }
}

,
, purchased restored, , , /, , finishTransaction. : consumable , , , .
, .
, 2: (, , UI , )

. purchasing (, ) deferred — (, ). UI.

ViewController, , , .

        @IBAction func purchaseAPressed(_ sender: UIButton) {
        showSpinner()
        Purchases.default.purchaseProduct(productId: "barcode_month_subscription") { [weak self] _ in
            self?.hideSpinner()
            // Handle result
        }
    }

    @IBAction func purchaseBPressed(_ sender: Any) {
        showSpinner()
        Purchases.default.purchaseProduct(productId: "barcode_year_subscription") { [weak self] _ in
            self?.hideSpinner()
            // Handle result
        }
    }

    @IBAction func restorePressed(_ sender: UIButton) {
        showSpinner()
        Purchases.default.restorePurchases { [weak self] _ in
            self?.hideSpinner()
            // Handle result
        }
    }

, . . x401om .

iOS应用内购买：初始化和处理购买

创建订阅屏幕

Purchases

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