当用户第一次被拒绝时，再次请求 iOS 人脸 ID 权限

Question

在为应用程序请求人脸 ID 权限后，我们会收到允许用户授予或拒绝使用此技术的 Apple 警报。

我的问题是：如果用户拒绝使用face id，是否有任何解决方案可以在不卸载应用程序的情况下再次请求它。

Answer 1

您可以再次请求，但方式与第一次不同。 您可以做的是，当您请求 Face ID 时，您应该检查授权状态，可以是notDetermined 、 authorized 、 denied或restricted 。

在未确定的情况下，您notDetermined您已经在执行的请求访问，如果被拒绝，您可以为用户提供 go 到 Settings -> YourAppName 的选项，以授予 FaceID 访问您的应用程序的权限。

这是取自以下答案的示例： 参考问题

它适用于相机访问，但您应该能够非常简单地将其应用于 FaceID。

@IBAction func goToCamera()
{
    let status = AVCaptureDevice.authorizationStatus(for: AVMediaType.video)
    switch (status) {
    case .authorized:
        self.popCamera()
    case .notDetermined:
        AVCaptureDevice.requestAccess(for: AVMediaType.video) { (granted) in
            if (granted) {
                self.popCamera()
            } else {
                self.camDenied()
            }
        }
    case .denied:
        self.camDenied()
    case .restricted:
        let alert = UIAlertController(title: "Restricted",
                                      message: "You've been restricted from using the camera on this device. Without camera access this feature won't work. Please contact the device owner so they can give you access.",
                                      preferredStyle: .alert)

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

然后在camDenied function 中：

func camDenied() {
    DispatchQueue.main.async {
            var alertText = "It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Close this app.\n\n2. Open the Settings app.\n\n3. Scroll to the bottom and select this app in the list.\n\n4. Turn the Camera on.\n\n5. Open this app and try again."

            var alertButton = "OK"
            var goAction = UIAlertAction(title: alertButton, style: .default, handler: nil)

            if UIApplication.shared.canOpenURL(URL(string: UIApplicationOpenSettingsURLString)!) {
                alertText = "It looks like your privacy settings are preventing us from accessing your camera to do barcode scanning. You can fix this by doing the following:\n\n1. Touch the Go button below to open the Settings app.\n\n2. Turn the Camera on.\n\n3. Open this app and try again."

                alertButton = "Go"

                goAction = UIAlertAction(title: alertButton, style: .default, handler: {(alert: UIAlertAction!) -> Void in
                    UIApplication.shared.open(URL(string: UIApplicationOpenSettingsURLString)!, options: [:], completionHandler: nil)
                })
            }

            let alert = UIAlertController(title: "Error", message: alertText, preferredStyle: .alert)
            alert.addAction(goAction)
            self.present(alert, animated: true, completion: nil)
    }
}