我无法将值传递给下一个视图控制器

Question

我正在开发一个应用程序，该应用程序向Firebase运行两个不同的查询。第一个Firebase查询显示pickerView中的数据，第二个是对"users"集合的查询并提取自定义字段。两个查询都按预期工作，pickerView显示信息，我可以将用户集合的结果打印到控制台。我遇到的问题是，我试图将自定义字段的值传递给下一个VC，但没有成功。我不确定我错过了什么。非常感谢您的帮助。这是我的代码：

class PatfilterVC: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate {
@IBOutlet weak var hospNameTxt: UITextField!
@IBOutlet weak var getDataBtn: UIButton!
@IBOutlet weak var infoPickerViewer: UIPickerView!
private var textFieldSelected = UITextField()
private var pickerView: UIPickerView?
private var handle: AuthStateDidChangeListenerHandle?
private var userListener: ListenerRegistration!
private var hospitalClass = [HospitalList]()
private var hospCollectionRef: CollectionReference!
private var hospCode: HospitalList! = nil
private var loggedInUserClass = [UserSpecialty]()
private var usersCollectionRef: CollectionReference!
private var currentUserSpecialty: UserSpecialty! = nil
override func viewDidLoad() {
super.viewDidLoad()
overrideUserInterfaceStyle = .light
let pickerView = UIPickerView()
infoPickerViewer.delegate = self
infoPickerViewer.dataSource = self
hospNameTxt.inputView = pickerView
hospNameTxt.delegate = self
self.infoPickerViewer = pickerView
self.infoPickerViewer?.delegate = self
self.infoPickerViewer?.dataSource = self
self.infoPickerViewer?.reloadAllComponents()
hospCollectionRef = Firestore.firestore().collection(HOSPITAL_REF)
usersCollectionRef = Firestore.firestore().collection(USERS_REF)
handle = Auth.auth().addStateDidChangeListener({ (auth, user) in
if user == nil {
self.getDataBtn.isUserInteractionEnabled = false
self.infoPickerViewer.isUserInteractionEnabled = false
} else {
self.getDataBtn.isUserInteractionEnabled = true
self.infoPickerViewer.isUserInteractionEnabled = true
self.setListener()
}
})
let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(UIInputViewController.dismissKeyboard))
view.addGestureRecognizer(tap)
getHospitalList()
getUserSpecialty()
}

@objc func dismissKeyboard() {
view.endEditing(true)
}
override func viewWillAppear(_ animated: Bool) {
handle = Auth.auth().addStateDidChangeListener({ (auth, user) in
if user == nil {
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let LoginVC = storyboard.instantiateViewController(withIdentifier: "LoginVC")
self.present(LoginVC, animated: true, completion: nil)
} else {
self.setListener()
}
})
}
override func viewWillDisappear(_ animated: Bool) {
if userListener != nil {
userListener.remove()
}
}
func setListener() {
}
func numberOfComponents(in pickerView: UIPickerView) -> Int {
return 1
}
func textFieldDidBeginEditing(_ textField: UITextField) {
textFieldSelected = textField
}
func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
self.pickerView?.reloadAllComponents()
return true
}
func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
return hospitalClass.count
}
func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
return hospitalClass[row].hospitalName
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
hospCode = hospitalClass[row]
let hosp = hospitalClass[row].hospitalName
hospNameTxt.text = hosp
}
@IBAction func getDataTapped(_ sender: Any) {
guard hospCode != nil else {return}
guard currentUserSpecialty != nil else {return}
performSegue(withIdentifier: "goToResults", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToResults" {
let vc = segue.destination as! ResultsdataVC
if let hosp = hospCode {
vc.hospCodeFromVC = hosp.hospitalCode
}
if let user = currentUserSpecialty {
vc.userSpecFromVC = user.userSpecialtyCode
}
}
}
//this query displays in the pickerView
func getHospitalList() {
let hospListQuery = hospCollectionRef?
.order(by: HOSPITAL_NAME, descending: false)
hospListQuery?.getDocuments { (snapshot, error) in
if let err = error {
debugPrint("error fetching docs: (err)")
} else {
self.infoPickerViewer.reloadAllComponents()
let snap = snapshot
for document in snap!.documents {
let data = document.data()
let hospitalCode = data[HOSPITAL_CODE] as? String ?? ""
let hospitalName = data[HOSPITAL_NAME] as? String ?? ""
let hospList = HospitalList(hospitalCode: hospitalCode, hospitalName: hospitalName)
self.hospitalClass.append(hospList)
}
}
}
}
//this query gets the values from Firebase but i cannot pass userSpecialtyCode
// to the next viewController
func getUserSpecialty() {
if let loggedInUser = Auth.auth().currentUser?.uid {
let docRef = usersCollectionRef.document(loggedInUser)
docRef.getDocument { ( document, error) in
if let document = document, document.exists {
let data = document.data()
let userSpecialtyCode = data?[SPECIALTY_CODE] as? String ?? ""
let loggedInUserId = data?[LOGGED_IN_USER_ID] as? String ?? ""
let loggedUser = UserSpecialty(userSpecialtyCode: userSpecialtyCode, loggedInUserId: loggedInUserId)
self.loggedInUserClass.append(loggedUser)
print("specCode", userSpecialtyCode as Any) //IT PRINTS THE CORRECT VALUE
print("loggedInUser", loggedInUserId as Any) //IT PRINTS THE USER ID
} else {
print("no document")
}
}
}
}

@IBAction func logoutTapped(_ sender: Any) {
let firebaseAuth = Auth.auth()
do {
try firebaseAuth.signOut()
} catch let signoutError as NSError {
debugPrint("Error signing out: (signoutError)")
}
}
}

Answer 1

尝试使用此

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToResults" {
let vc = segue.destination as! ResultsdataVC
_ = vc.view
if let hosp = hospCode {
vc.hospCodeFromVC = hosp.hospitalCode
}
if let user = currentUserSpecialty {
vc.userSpecFromVC = user.userSpecialtyCode
}
}
}