iOS：调用AppDelegate的打开URL时，不会显示Touch Id

Question

我的应用程序支持从其他应用程序打开图像，pdf等文档。触摸ID实现如下所示，当应用程序到达前台时请求它

NotificationCenter.default.addObserver(forName: .UIApplicationWillEnterForeground, object: nil, queue: .main) { (notification) in
        LAContext().evaluatePolicy( .deviceOwnerAuthenticationWithBiometrics, localizedReason: "Request Touch ID", reply: { [unowned self] (success, error) -> Void in
             if (success) {

             } else {

             }
})

现在，当用户从后台或重新启动时打开应用程序时，请求Touch Id正常工作。从其他应用程序打开应用程序时会出现问题，例如点击应用程序URL，使用“复制到MyApp”选项从外部应用程序共享文档，其中AppDelegate的打开URL方法被调用，如下所示

public func application(_ app: UIApplication, open url: URL, options: [UIApplicationOpenURLOptionsKey : Any] = [:]) -> Bool {
    //validate and save url
    return true
}

问题是当从外部应用程序启动应用程序时，会调用上面的open url方法，并且还会按预期调用UIApplicationWillEnterForeground观察器。但是在那个UIApplicationWillEnterForeground观察者中，LAContext（）。evaluatePolicy突然失败并显示“调用者移动到后台”错误。

注意，问题可以在iOS 11.0.3,11.3上看到，而iOS 11.4或<11则无法重现

Answer 1

当app是applicationDidBecomeActive时你需要添加它

NotificationCenter.default.addObserver(forName: .UIApplicationDidBecomeActive, object: nil, queue: .main) { (notification) in

let context = LAContext()

var error: NSError?

if context.canEvaluatePolicy(
    LAPolicy.deviceOwnerAuthenticationWithBiometrics,
    error: &error) {

    // Device can use biometric authentication
    context.evaluatePolicy(
        LAPolicy.deviceOwnerAuthenticationWithBiometrics,
        localizedReason: "Access requires authentication",
        reply: {(success, error) in
            DispatchQueue.main.async {

                if let err = error {

                    switch err._code {

                    case LAError.Code.systemCancel.rawValue:
                        self.notifyUser("Session cancelled",
                                        err: err.localizedDescription)

                    case LAError.Code.userCancel.rawValue:
                        self.notifyUser("Please try again",
                                        err: err.localizedDescription)

                    case LAError.Code.userFallback.rawValue:
                        self.notifyUser("Authentication",
                                        err: "Password option selected")
                        // Custom code to obtain password here

                    default:
                        self.notifyUser("Authentication failed",
                                        err: err.localizedDescription)
                    }

                } else {
                    self.notifyUser("Authentication Successful",
                                    err: "You now have full access")
                }
            }
    })

}

})