当我实际上可以访问该标识符时如何修复错误 "Use of Unresolved identifier"

Question

我有一个 class 被定义为单例，我尝试从那个 class 访问 2 个函数，但我得到一个错误，说 class 不能可以找到，但是当我按下 Cmd + Click 时，我可以导航到那个 class。我重新启动 xCode 很多次，我也尝试使用 xCode 10 和 xCode 9...同样的错误。我不知道如何解决它。

这是我的代码：

// First Class
class BankAccount {

    private init() {}

    static let bankAccountKey = "Bank Account"
    static let suiteName = "group.com.YourName"

    // Function to set the balance for ShoppingLand Bank
    static func setBalance(toAmount amount: Double) {
        guard let defaults = UserDefaults(suiteName: suiteName) else { return }
        defaults.set(amount, forKey: bankAccountKey)
        defaults.synchronize()
    }

    // Function to check new updates about the balance of ShoppingLand Bank
    static func checkBalance() -> Double? {
        guard let defaults = UserDefaults(suiteName: suiteName) else { return nil }
        defaults.synchronize()
        let balance = defaults.double(forKey: bankAccountKey)
        return balance
    }

    @discardableResult
    static func withdraw(amount: Double) -> Double? {
        guard let defaults = UserDefaults(suiteName: suiteName) else { return nil }
        let balance = defaults.double(forKey: bankAccountKey)
        let newBalance = balance - amount
        setBalance(toAmount: newBalance)
        return newBalance
    }

    @discardableResult
    static func deposit(amount: Double) -> Double? {
        guard let defaults = UserDefaults(suiteName: suiteName) else { return nil }
        let balance = defaults.double(forKey: bankAccountKey)
        let newBalance = balance + amount
        setBalance(toAmount: newBalance)
        return newBalance
    }
}

// Second Class

import Intents

class IntentHandler: INExtension {}

extension IntentHandler: INSendPaymentIntentHandling {
    func handle(intent: INSendPaymentIntent, completion: @escaping (INSendPaymentIntentResponse) -> Void) {

        guard let amount = intent.currencyAmount?.amount?.doubleValue else {
            completion(INSendPaymentIntentResponse(code: .failure, userActivity: nil))
            return
        }

        BankAccount.withdraw(amount: amount)
        completion(INSendPaymentIntentResponse(code: .success, userActivity: nil))
    }
}


extension IntentHandler: INRequestPaymentIntentHandling {
    func handle(intent: INRequestPaymentIntent, completion: @escaping (INRequestPaymentIntentResponse) -> Void) {

        guard let amount = intent.currencyAmount?.amount?.doubleValue else {
            completion(INRequestPaymentIntentResponse(code: .failure, userActivity: nil))
            return
        }
        BankAccount.deposit(amount: amount)
        completion(INRequestPaymentIntentResponse(code: .success, userActivity: nil))

    }
}

这是一个演示：

http://recordit.co/NoXKlT3dw1

感谢您的宝贵时间！

Answer 1

您没有正确设置单例。 BankAccount 是一个 class，不是实例。单例是 class 的一个版本，其中只会访问一个实例，但您仍在访问一个实例。您需要添加：

class BankAccount {
    static let shared = BankAccount()
    ...

到您的银行帐户 class。 shared 属性是实际的单例实例。稍后当您尝试访问单例时，而不是

BankAccount.withdraw(amount: amount)

您想使用该实例：

BankAccount.shared.withdraw(amount: amount)

Answer 2

确保您的 class BankAccount 文件可用于您的其他目标 -> ShoppingLandSiri。您可以从文件检查器视图中查看它。

当我实际上可以访问该标识符时如何修复错误 "Use of Unresolved identifier"

How to fix the error "Use of Unresolved identifier" when actually I can access that identifier

ios

swift

swift4

sirikit