在 NSObject 类中设置协议并在 UIViewController 类中调用它们

Posted 2023-03-13

【中文标题】在 NSObject 类中设置协议并在 UIViewController 类中调用它们

【英文标题】：Set protocols in an NSObject class and call them in a UIViewController class

【发布时间】：2017-07-19 19:01:13

【问题描述】：

我是 swift 新手，我只是想知道有没有办法在 NSObject 类中声明一些委托协议并在 UIViewController 类中调用它们。我试过这样做，它会引发运行时异常。我在类中的代码如下。

NSObject 类

import UIKit
import StoreKit
class InAppPurchase: NSObject, SKProductsRequestDelegate, SKPaymentTransactionObserver 
var productsList = [SKProduct]()
    var productToPurchase = SKProduct()
    var productID = ""
    let PURCHASE_ID_PREFIX = "com.aux.ApplePaySample."


    public func initPayment (productID: String) 
        self.productID = PURCHASE_ID_PREFIX + productID
        print("Initializing Purchase Product ID: \(self.productID)")
        if SKPaymentQueue.canMakePayments() 
            let productID: NSSet = NSSet(objects: self.productID)
            let request: SKProductsRequest = SKProductsRequest(productIdentifiers: productID as! Set<String>)
            request.delegate = self
            request.start()
        else 
            print("In App Purchases not enabled")
        
    

    func buyProduct() 
        let payment = SKPayment(product: productToPurchase)
        SKPaymentQueue.default().add(self)
        SKPaymentQueue.default().add(payment as SKPayment)
    


    public func productsRequest(_ request: SKProductsRequest, didReceive response: SKProductsResponse) 
        let myProducts = response.products
        for product in myProducts 
            print("\(product.productIdentifier) \(product.price) \(product.localizedDescription)")
            productsList.append(product)
        

        for product in productsList 
            let productID = product.productIdentifier
            if productID == self.productID 
                productToPurchase = product
                buyProduct()
            
        

    

UIViewController 类

import UIKit
import StoreKit

class InAppViewController: UIViewController
    @IBOutlet var buyButton: UIButton!
    // SKProductsRequestDelegate, SKPaymentTransactionObserver 
    let defaults = UserDefaults.standard
    var product_id: NSString?
    override func viewDidLoad() 
        super.viewDidLoad()

    InAppPurchase().initPayment(productID: "101")

从技术上讲，我的 initPayment 方法应该触发代表，但它没有发生，我没有得到我在这里缺少的东西。非常感谢您的帮助。

【参考方案1】：

应该像下面这样创建一个实例

static var shared:InAppPurchase = 
        return InAppPurchase()
    ()

【参考方案2】：

您没有保留 InAppPurchase 对象。在调用委托之前，它可能会被释放并设置为 nil。

尝试创建一个类变量var iap: InAppPurchase，然后在实例化您的类时分配给该变量。

iap = InAppPurchase()
iap.initPayment(productID: "101")

这应该保留您的实例并允许它接收委托方法调用。