人脸ID评估流程无法正常运行 [英] Face ID evaluation process not working properly

问题描述

我正在尝试获取以下功能中的Face ID或Touch ID成功

I'm trying to get if Face ID or Touch ID succeeded in the function below

func authenticate() -> Bool{

    let context = LAContext()
    var error: NSError?

    guard context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) else {
        return false
    }
    var returnValue = false
    let reason = "Face ID authentication"
    context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason) 
    {
        isAuthorized, error in
        guard isAuthorized == true else {
            return print(error)
        }
        returnValue = true
        print("success")
    }
    return returnValue        
}

，但是即使此代码成功执行，它也会跳过returnValue = true，稍后会传递错误的返回值. 为什么会这样?以及如何修复此代码以使其像预期的那样工作?

but even when it succeeds with this code it skips the returnValue = true is passed later which results a false return. why does this happen? and how can I fix this code to make it work like it is suppose to?

上面的代码来自此链接 万一这个人在看，谢谢.

the code above is from this link just in case this person was watching, thank you.

推荐答案

Touch ID的工作代码&面部ID LocalAuthentication (Swift 4代码)

Working code of Touch ID & Face ID LocalAuthentication (swift 4 Code)

注意:隐私-面部ID使用说明键添加到Info.plist

Note : Privacy - Face ID Usage Description key add in Info.plist

使用

self.Authenticate { (success) in
     print(success)
}

本地身份验证功能

func Authenticate(completion: @escaping ((Bool) -> ())){

    //Create a context
    let authenticationContext = LAContext()
    var error:NSError?

    //Check if device have Biometric sensor
    let isValidSensor : Bool = authenticationContext.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error)

    if isValidSensor {
        //Device have BiometricSensor
        //It Supports TouchID

        authenticationContext.evaluatePolicy(
            .deviceOwnerAuthenticationWithBiometrics,
            localizedReason: "Touch / Face ID authentication",
            reply: { [unowned self] (success, error) -> Void in

                if(success) {
                    // Touch / Face ID recognized success here
                    completion(true)
                } else {
                    //If not recognized then
                    if let error = error {
                        let strMessage = self.errorMessage(errorCode: error._code)
                        if strMessage != ""{
                            self.showAlertWithTitle(title: "Error", message: strMessage)
                        }
                    }
                    completion(false)
                }
        })
    } else {

        let strMessage = self.errorMessage(errorCode: (error?._code)!)
        if strMessage != ""{
            self.showAlertWithTitle(title: "Error", message: strMessage)
        }
    }

}

处理带有消息的错误代码

Handle Error Codes with Messages

//MARK: TouchID error
func errorMessage(errorCode:Int) -> String{

    var strMessage = ""

    switch errorCode {

    case LAError.Code.authenticationFailed.rawValue:
        strMessage = "Authentication Failed"

    case LAError.Code.userCancel.rawValue:
        strMessage = "User Cancel"

    case LAError.Code.systemCancel.rawValue:
        strMessage = "System Cancel"

    case LAError.Code.passcodeNotSet.rawValue:
        strMessage = "Please goto the Settings & Turn On Passcode"

    case LAError.Code.touchIDNotAvailable.rawValue:
        strMessage = "TouchI or FaceID DNot Available"

    case LAError.Code.touchIDNotEnrolled.rawValue:
        strMessage = "TouchID or FaceID Not Enrolled"

    case LAError.Code.touchIDLockout.rawValue:
        strMessage = "TouchID or FaceID Lockout Please goto the Settings & Turn On Passcode"

    case LAError.Code.appCancel.rawValue:
        strMessage = "App Cancel"

    case LAError.Code.invalidContext.rawValue:
        strMessage = "Invalid Context"

    default:
        strMessage = ""

    }
    return strMessage
}

显示警报消息

//MARK: Show Alert
func showAlertWithTitle( title:String, message:String ) {
    let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)

    let actionOk = UIAlertAction(title: "OK", style: .default, handler: nil)
    alert.addAction(actionOk)
    self.present(alert, animated: true, completion: nil)
}

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