尝试快速将协议添加到类签名中

Question

我正在尝试快速创建应用内购买。在我的班级签名中，我有以下内容：

class ViewController: UIViewController, UITextFieldDelegate, UIAlertViewDelegate,   
SKStoreProductViewControllerDelegate, SKPaymentTransactionObserver{

但是，我收到一条错误消息：类型“ViewController”不符合协议：SKPaymentTransactionObserver

我读过这个：https://developer.apple.com/library/prerelease/mac/documentation/Swift/Conceptual/BuildingCocoaApps/WritingSwiftClassesWithObjective-CBehavior.html 和 Conform to protocol in ViewController, in Swift

SKSoreProductViewControllerDelegate 工作正常。请问我错过了什么？

Answer 1

你是否在你的类中实现了所需的方法？

paymentQueue:updatedTransactions: 和 paymentQueue:updatedDownloads: 是必需的方法，如果它们没有实现，你会收到警告。

Answer 2

SKPaymentTransactionProtocol 有这些方法：

func paymentQueue(queue: SKPaymentQueue!, updatedTransactions transactions: [AnyObject]!) 
@optional func paymentQueue(queue: SKPaymentQueue!, removedTransactions transactions: [AnyObject]!)
@optional func paymentQueue(queue: SKPaymentQueue!, restoreCompletedTransactionsFailedWithError error: NSError!)
@optional func paymentQueueRestoreCompletedTransactionsFinished(queue: SKPaymentQueue!)
@optional func paymentQueue(queue: SKPaymentQueue!, updatedDownloads downloads: [AnyObject]!)

第一个方法是您的类必须实现以符合协议的必需方法。将其添加到您的 ViewController 中，错误就会消失。

class ViewController: UIViewController, UITextFieldDelegate, UIAlertViewDelegate,   
SKStoreProductViewControllerDelegate, SKPaymentTransactionObserver{
    func paymentQueue(queue: SKPaymentQueue!, updatedTransactions transactions: [AnyObject]!){/*...*/}
    /*...*/
}

Answer 3

为了快速使用这个：

public func paymentQueue(queue: SKPaymentQueue, updatedTransactions transactions: [SKPaymentTransaction]) { /* */ }

而不是这个：

public func paymentQueue(queue: SKPaymentQueue!, updatedTransactions transactions: [AnyObject]!) { /* */ }