Question

我试图根据touch id的成功/失败返回true或false。但是当调用条件成功时，函数将以false值退出。我是iOS开发的新手。我相信我应该使用某种完成处理程序，但在这种特殊情况下我不明白该怎么做。

func authenticateUser(reasonString: String) -> Bool {
    // Get the local authentication context.
    let context = LAContext()

    // Declare a NSError variable.
    var error: NSError?

    // Current authorization status of user
    var isAuthorized = false

    // Check if the device can evaluate the policy.
    if context.canEvaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, error: &error) {
        [context .evaluatePolicy(LAPolicy.DeviceOwnerAuthenticationWithBiometrics, localizedReason: reasonString, reply: { (success: Bool, evalPolicyError: NSError?) -> Void in

            if success {
                isAuthorized = true
            }
            else{
                // If authentication failed then show a message to the console with a short description.
                // In case that the error is a user fallback, then show the password alert view.
                print(evalPolicyError?.localizedDescription)

                switch evalPolicyError!.code {

                case LAError.SystemCancel.rawValue:
                    print("Authentication was cancelled by the system")

                case LAError.UserCancel.rawValue:
                    print("Authentication was cancelled by the user")

                case LAError.UserFallback.rawValue:
                    print("User selected to enter custom password")

                default:
                    print("Authentication failed")

                }
            }

        })]
    }
    else{
        // If the security policy cannot be evaluated then show a short message depending on the error.
        switch error!.code{

        case LAError.TouchIDNotEnrolled.rawValue:
            print("TouchID is not enrolled")

        case LAError.PasscodeNotSet.rawValue:
            print("A passcode has not been set")

        default:
            // The LAError.TouchIDNotAvailable case.
            print("TouchID not available")
        }

        // Optionally the error description can be displayed on the console.
        print(error?.localizedDescription)

    }
return isAuthorized
}

即使在执行touchID部分之前，此函数也会返回false。有人可以指导吗？

Answer 1

您的函数authenticateUser将始终返回false，因为您返回isAuthorized值，设置为ti false。 context.canEvaluatePolicy和context.evaluatePolicy仍在执行，并且isAuthorized的值不会更改。

实际流量有点像这样：

设置isAuthorized == false

{call context.canEvaluatePolicy - ＆gt;还在执行 call context.evaluatePolicy - ＆gt;关于context.canEvaluatePolicy}

的成功

Return isAuthorized = False - ＆gt; context.canEvaluatePolicy和context.evaluatePolicy仍在执行。

执行流程完成方法执行，即使正在执行块方法。

我的建议是从函数末尾删除return isAuthorized并实现成功和失败块。

成功时触摸ID设置变量

1 个答案: