ios - Controller 在应用程序访问之前就已初始化

Question

所以问题似乎出在我的 profileViewController 上。在这段代码中完成注册后，我设置了当前用户。

class func setCurrent(_ user: User, writeToUserDefaults: Bool = true) {
        print(user)
        print("")
        if writeToUserDefaults {
            let data = NSKeyedArchiver.archivedData(withRootObject: user)

            UserDefaults.standard.set(data, forKey: "currentUser")
            UserDefaults.standard.synchronize()
        }
        _current = user
        print(_current)
    }

然后，它会转到我的 profileViewController 并尝试查找用户，结果发现该用户为空。为什么在我进入 View Controller 之前它就去那里了。为什么为零？下面是我的个人资料 View Controller 和我的 viewDidLoad

 class ProfileeViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
        var profileHandle: DatabaseHandle = 0
        var profileRef: DatabaseReference?
        let cellID = "cellID"
        let profileSetupTransition = AlterProfileViewController()
        let settingView = SettingsViewController()
        var userEvents = [Event]()
        var userId: String?
        var user: User?
        var emptyLabel: UILabel?

        var currentUserName: String = ""


        override func viewDidLoad() {
            super.viewDidLoad()
            collectionView?.backgroundColor = UIColor.white
            let user = self.user ?? User.current

            profileHandle = UserService.observeProfile(for: user) { [unowned self](ref, user, events) in
                self.profileRef = ref
                self.user = user
                self.userEvents = events
                // self.jobs = allJobs
                // self.reciepts = allReciepts

                // print(self.userEvents)
                //  print(self.reciepts)
                DispatchQueue.main.async {
                    self.collectionView?.reloadData()
                }

            }

我调用 setCurrent 的方法如下

   // will handle the  sign up of a user
    @objc func handleSignUp(){
        // first we cant to take sure that all of the fields are filled
        var profilePic: String = ""
        // will take the user selected image and load it to firebase
        let imageName = NSUUID().uuidString
        guard let username = self.nameTextField.text,
            let confirmPassword = self.confirmPasswordTextField.text,
            let email = self.emailTextField.text,
            let password = self.passwordTextField.text,
            !username.isEmpty,
            !email.isEmpty,
            !password.isEmpty,
            !confirmPassword.isEmpty
            else {
                print("Required fields are not all filled!")
                return
        }
        if self.validateEmail(enteredEmail:email) != true{
            let alertController = UIAlertController(title: "Error", message: "Please Enter A Valid Email", preferredStyle: .alert)
            let defaultAction = UIAlertAction(title: "Ok", style: .cancel, handler: nil)
            alertController.addAction(defaultAction)
            self.present(alertController, animated: true, completion: nil)
        }
        // will make sure user is validated before it even tries to create user
        // will make sure the password and confirm password textfields have the same value if so it will print an error
        if self.passwordTextField.text != self.confirmPasswordTextField.text {
            let alertController = UIAlertController(title: "Error", message: "Passwords Don't Match", preferredStyle: .alert)
            let defaultAction = UIAlertAction(title: "Ok", style: .cancel, handler: nil)
            alertController.addAction(defaultAction)
            self.present(alertController, animated: true, completion: nil)
        }
        //create a reference to the sotrage database in firebase
        let storageRef = Storage.storage().reference().child("profile_images").child("\(imageName).PNG")
        //following function does the work of putting it into firebase
        //notice I also set the value of profilepic oo it can be saved in the updated user instance in the database
        if let userImage = selectedImageFromPicker,let uploadData = UIImageJPEGRepresentation(userImage, 0.1){
            AuthService.createUser(controller: self, email: email, password: password) { (authUser) in
                guard let firUser = authUser else{
                    return
                }
                storageRef.putData(uploadData, metadata: nil, completion: { (metadata, error) in
                    if error != nil {
                        print(error ?? "")
                        return
                    }
                    profilePic = (metadata?.downloadURL()!.absoluteString)!
                    //printing to make sure values are contained in these strings
                    print(profilePic)
                    print(username)

                    UserService.create(firUser, username: username, profilePic: profilePic, location: self.userLocation!, completion: { (user) in
                        guard let user = user else {
                            print("User not loaded into firebase db")
                            return
                        }
                        User.setCurrent(user, writeToUserDefaults: true)
                        // will set the current user for userdefaults to work
                        print(user.profilePic ?? "")
                        print(user.username ?? "")

                        // self.delegate?.finishSigningUp()
                        self.finishSigningUp()

                    })
                })
            }
        }
    }

然后调用该方法将用户移动到homeviewController并设置为root

func finishSigningUp() {
    print("Finish signing up from signup view controller")
    print("Attempting to return to root view controller")
    let homeController = HomeViewController()
    //should change the root view controller to the homecontroller when done signing up
    self.view.window?.rootViewController = homeController
    self.view.window?.makeKeyAndVisible()
}

Answer 1

当您这样做时，User.current 将在用户默认值上检索您之前在 setCurrent 方法中保存在用户默认值上的当前用户，对吗？

您是否检查过用户是否使用“currentUser”键正确保存在用户默认值中？也许这就是它为零的原因。

为什么在我进入 View Controller 之前它会去那里？也许你正在做一些异步方法计算，即使它还没有完成，你也会移动到 vie Controller 。您在没有异步方法结果的情况下转移到它，并且您的值为零是逻辑，因为您不允许设置它们。这是一个假设，因为我看到了您的代码，并且您在代码流上调用了一些异步方法。