ios - Swift - 后台线程通过身份验证使应用程序崩溃

Question

我正在尝试将面容 ID/触控 ID/代码添加到我的应用程序，但我在终止它时遇到了一些问题:这是我得到的错误(在一次运行和另一次运行之间略有不同，例如标识符的数量发生变化):

Can't end BackgroundTask: no background task exists with identifier 12 (0xc), or it may have already been ended. Break in UIApplicationEndBackgroundTaskError() to debug.

我尝试按照说明进行操作，但我不知道该怎么做。在互联网上我发现这可能是 iOS 13 导致的错误，但我没有任何运行 iOS 12 的设备来测试它。

我的设置中没有任何崩溃日志。

这是导致错误的代码:

import UIKit
import LocalAuthentication

class LoginController: VController {

override func viewDidLoad() {
    super.viewDidLoad()

    let context = LAContext()
    var error: NSError?
    let reason = "Identificati"

    if context.canEvaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, error: &error) {
        context.evaluatePolicy(.deviceOwnerAuthenticationWithBiometrics, localizedReason: reason) { (success, err) in
            DispatchQueue.main.async {
                if success {
                    context.invalidate()
                    let layout = UICollectionViewFlowLayout.init()
                    let dim = (UIScreen.main.bounds.width / 2) - 12
                    layout.itemSize = CGSize(width: dim, height: dim)
                    layout.sectionInset = UIEdgeInsets(top: 6, left: 6, bottom: 6, right: 6)
                    let vc = UINavigationController(rootViewController: ViewController(collectionViewLayout: layout))
                    vc.modalPresentationStyle = .fullScreen
                    self.present(vc, animated: true, completion: nil)
                } else {
                    print(err!.localizedDescription)
                }
            }
        }

    } else {
        if context.canEvaluatePolicy(.deviceOwnerAuthentication, error: &error) {
            context.evaluatePolicy(.deviceOwnerAuthentication, localizedReason: reason) { (success, err) in
                DispatchQueue.main.async {
                    if success {
                        context.invalidate()
                        let layout = UICollectionViewFlowLayout.init()
                        let dim = (UIScreen.main.bounds.width / 2) - 12
                        layout.itemSize = CGSize(width: dim, height: dim)
                        layout.sectionInset = UIEdgeInsets(top: 6, left: 6, bottom: 6, right: 6)
                        let vc = UINavigationController(rootViewController: ViewController(collectionViewLayout: layout))
                        vc.modalPresentationStyle = .fullScreen
                        self.present(vc, animated: true, completion: nil)
                    } else {
                        print(err!.localizedDescription)
                    }
                }
            }

        } else {
            // Nothing worked
        }
    }
  }

}

Answer 1

调用 invalidate()完成后在您的上下文中运行。