ios - 如何使用 touchIDAuthenticationAllowableReuseDuration

Question

我在应用程序启动或进入前台时通过 LAContext 对用户进行身份验证。如果设备被锁定，则将要求用户两次授权自己。为避免这种行为，我将 context.touchIDAuthenticationAllowableReuseDuration 值设置为 240，但它没有按预期工作。用户还是要给自己授权两次。我做错了什么？

---

import LocalAuthentication

class AccessControl {

    internal var context = LAContext()
    private var policy: LAPolicy = .deviceOwnerAuthentication
    private var reason: String = NSLocalizedString("auhenticationLocalizedFallbackTitle", comment: "")

    init() {
        context.touchIDAuthenticationAllowableReuseDuration = 240
    }

    func evaluateUserWithBiometricsOrPasscode(success: @escaping () -> Void, error: @escaping () -> Void) {

        guard context.canEvaluatePolicy(policy, error: nil) else {
            error()
            return
        }
        context.evaluatePolicy(policy, localizedReason: reason) { eStatus, eError in
            DispatchQueue.main.async {
                if eStatus {
                    success()
                } else {
                    error()
                }
            }
        }
    }

}

Answer 1

您需要每次都使用相同的 LAContext 对象才能获得该行为。

class AccessControl {

    // MARK: - Singleton
    public static let shared = AccessControl()

    // Policy
    private var policy: LAPolicy = .deviceOwnerAuthentication

    // Reason
    private var reason: String = NSLocalizedString("auhenticationLocalizedFallbackTitle", comment: "")

    // Context
    lazy var context: LAContext = {
        let mainContext = LAContext()
        if #available(iOS 9.0, *) {
            // specify your interval
            mainContext.touchIDAuthenticationAllowableReuseDuration = 60
        }
        return mainContext
    }()


    // Evaluate
    func evaluateUserWithBiometricsOrPasscode(success: @escaping () -> Void, error: @escaping () -> Void) {

        guard context.canEvaluatePolicy(policy, error: nil) else {
            error()
            return
        }
        context.evaluatePolicy(policy, localizedReason: reason) { eStatus, eError in
            DispatchQueue.main.async {
                if eStatus {
                    success()
                } else {
                    error()
                }
            }
        }
    }
}

并像下面这样调用此函数:这也适用于FaceID 身份验证。

AccessControl.shared.evaluateUserWithBiometricsOrPasscode(success: {

}) {

}