您如何让位置捕获器在覆盖转场之前运行？

Question

So, I need to capture user's location (with their permission of course) before he gets to homepage. So on the login/register page I want to capture the location, but I need to do it before the override segue to homepage for logged in users. Any of you have any ideas? Below is the override segue.

I put location capturer before the segue in the override function, but it still went to homepage before the user had an opportunity to accept share location. This is not really unexpected since the entire override function is by definition an override function

  override func viewDidAppear(_ animated: Bool) {
//////////////////////
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])   {

    let databaseRef = Database.database().reference()
    guard let uid = Auth.auth().currentUser?.uid else { return }
    guard let locValue: CLLocationCoordinate2D = manager.location?.coordinate else { return }
    print("locations = \(locValue.latitude) \(locValue.longitude)")
    latestLocation = ["latitude" : locValue.latitude, "longitude" : locValue.longitude]
    let lat = locValue.latitude
    let lon = locValue.longitude
    dict = CLLocation(latitude: lat, longitude: lon)
    print("dict", dict)
    if let locationDictionary = latestLocation {           
databaseRef.child("people").child(uid).child("Coordinates").setValue(locationDictionary)  
    }   
}
//////////////////////
 if  Auth.auth().currentUser != nil {
        self.performSegue(withIdentifier: "tohome", sender: nil)
    }
}

Update: This is how I login and register.

    @IBAction func RegisterPressed(_ sender: Any) {
        
        Auth.auth().createUser(withEmail: (emailField.text ?? ""), password: (passwordField.text ?? ""))  { (user, error) in
            if let _eror = error {
                //something bad happning
                print(_eror.localizedDescription )
                let alert = UIAlertController(title: "Error", message: "Invalid Entry or Duplicate.", preferredStyle: UIAlertController.Style.alert)
                let action = UIAlertAction(title: "Ok", style: .default, handler: nil)
                alert.addAction(action)
                self.present(alert, animated: true, completion: nil)
                
            }else{
                //user registered successfully
                print(user as Any)
                if let userID = user?.user.uid
                {
                    KeychainWrapper.standard.set((userID), forKey: "uid")
                    
                    let databaseRef = Database.database().reference()
                    
                    databaseRef.child("A1").child(userID).child("users").setValue(self.emailField.text!)
                    databaseRef.child("people").child(userID).child("postID").setValue(userID)
                    let components = self.emailField.text!.split(separator: "@")
                    let child1 = components[0] //will be jake
                    let child2 = components[1] //will be aol.com
                    print(components, child1, child2, "childs")
                    databaseRef.child("people").child(userID).child("e2").setValue(child2)


                    components.forEach { print($0) }
                    
                    
                    

                    
                    self.performSegue(withIdentifier: "tohome", sender: nil)
                }
                
            }
        }
    }
     @IBAction func loginInPressed(_ sender: Any) {
 Auth.auth().signIn(withEmail: (emailField.text ?? ""), password: (passwordField.text ?? ""))  { (user, error) in
    if let _eror = error {
                   //something bad happning
                   print(_eror.localizedDescription )
                let alert = UIAlertController(title: "Error", message: "Incorrect Email or Password.", preferredStyle: UIAlertController.Style.alert)
                                     let action = UIAlertAction(title: "Ok", style: .default, handler: nil)
                                     alert.addAction(action)
                                     self.present(alert, animated: true, completion: nil)

               }else{
                   //user registered successfully
                   print(user as Any)
                        if let userID = user?.user.uid
 {
                            KeychainWrapper.standard.set((userID), forKey: "uid")
                            self.performSegue(withIdentifier: "tohome", sender: nil) }

               }
            }
    }

Answer 1

If I understand it correctly in viewDidAppear(_:) you have one condition. If it's true you immediately trying to perform the segue.

if  Auth.auth().currentUser != nil {
    self.performSegue(withIdentifier: "tohome", sender: nil)
}

As location is must to move into HomeScreen , why don't you do the navigation( segue ) when you receive the first location update inside CLLocationManagerDelegate ?

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation])   {
      // check for existing location if we received earlier
      guard self.latestLoc == nil else {
         // we received one location earlier, navigation to Home completed. no need to proceed 
         // If we no longer need to listen for loc updates, we can stop listening further
         manager.stopUpdatingLocation()
         return
      } 
      // ... Your exiting data base update code
     guard let latestLoc = locations.last else { return }
     self.latestLoc = latestLoc // If you want to pass this location to destination view controller in `prepare(for: UIStoryboardSegue, sender: Any?)`
     // Also it will good practice to call manager.stopUpdatingLocation() if you need location only for once 

     // Now move to HomeScreen
     self.performSegue(withIdentifier: "tohome", sender: nil)

     // If we no longer need to listen for loc updates, we can stop listening further
     manager.stopUpdatingLocation()
}