I'm trying to pass a text from a text field in a view controller to a label in a second view controller via prepareForSegue, but it's not working.
My code so far:
class ViewController: UIViewController {
#IBOutlet weak var inputTextField: UITextField!
// use of override func prepare gives an error
func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
var DestViewController: secondViewController = segue.destination as! secondViewController
DestViewController.labelText = inputTextField.text!
}
}
class SecondViewController: UIViewController {
#IBOutlet weak var receivedTextLabel: UILabel!
var labelText = "ss"
override func viewDidLoad() {
super.viewDidLoad()
receivedTextLabel.text! = labelText
}
}
If I use override for prepareForSegue, I get the following error:
Method does not override any method from it's superclass
Without overriding, it builds, but after performing the segue from the button to SecondViewController, the label's text doesn't get updated.
The method changed back in Swift 3 from prepareForSegue(segue:sender) to prepare(for:sender:). Replace it with the following:
override func prepare(for segue: UIStoryboardSegue, sender: Any?)
Related
I am trying to use segues to pass the data entered in the partyID text field to the partyID label in a separate view controller. However, I am getting errors in my code.
class PartyViewController: UIViewController {
// CALLS LOGIN VC
var LoginViewController: LoginViewController?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBOutlet weak var partyID: UITextField!
var token = String()
#IBAction func startParty(_ sender: UIButton) {
self.performSegue(withIdentifier: "partyVCtoGuestPartyVC", sender: self)
performSegue(withIdentifier: "hostStartParty", sender: self)
//LoginViewController?.fetchSpotifyProfile(accessToken )
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "partyVCtoGuestPartyVC"){
let GuestPartyVC = segue.destination as! GuestPartyViewController
GuestPartyVC.partyID = partyID.text
}
And here is the view controller I am trying to pass the data to:
class GuestPartyViewController: UIViewController {
#IBOutlet weak var partyID: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
partyIDLabel.text = partyID
// Do any additional setup after loading the view.
}
I get errors in my override func in LoginVC and then in the partyIDlabel.text in the GuestPartyVC.
In GuestPartyViewController
class GuestPartyViewController: UIViewController {
#IBOutlet weak var partyIDLabel: UILabel!
var partyID: String?
override func viewDidLoad() {
super.viewDidLoad()
partyIDLabel.text = partyID ?? ""
}
}
In PartyViewController
class PartyViewController: UIViewController {
#IBOutlet weak var partyID: UITextField!
#IBAction func startParty(_ sender: UIButton) {
self.performSegue(withIdentifier: "partyVCtoGuestPartyVC", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "partyVCtoGuestPartyVC",
let GuestPartyVC = segue.destination as? GuestPartyViewController {
GuestPartyVC.partyID = partyID.text
}
}
}
The IBOutlet is weak and may not be instantiate when you pass the text.
Could you try to pass the text in a property, then assign it in the viewDidLoad ?
class GuestPartyViewController: UIViewController {
#IBOutlet weak var partyID: UILabel!
var passedText: String?
override func viewDidLoad() {
super.viewDidLoad()
if let unwrappedPassedText = passedText {
partyIDLabel.text = partyID
}
}
// In the other controller
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "partyVCtoGuestPartyVC") {
let GuestPartyVC = segue.destination as! GuestPartyViewController
GuestPartyVC.passedText = partyID.text
}
first change the call of login VC
var LoginViewController = LoginViewController()
then put this before the view did load method
#IBOutlet weak var partyID: UITextField!
and can you send the error that you get
I am trying to perform a segue from a UITableView with news. If you push one of the news, it performs a segue to the specific news you selected.
It is easy and I have done it a few times... but I don't know what am I doing wrong this time.
The NewsDetailViewController is like this:
class NewsDetailViewController: UIViewController {
#IBOutlet weak var newsImage: UIImageView!
#IBOutlet weak var newsTitle: UILabel!
#IBOutlet weak var newsDate: UILabel!
#IBOutlet weak var newsText: UILabel!
var newsLink: String?
override func viewDidLoad() {
super.viewDidLoad()
// Hides the navigation bar.
self.navigationController?.setNavigationBarHidden(true, animated: false)
}
#IBAction func closeNews(_ sender: UIButton) {
navigationController?.popViewController(animated: true)
}
}
And the segue in the NewsTableViewController is like this:
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("you selected the row: \(indexPath.row)")
tableView.deselectRow(at: indexPath, animated: true)
self.performSegue(withIdentifier: "goToNewsDetail", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToNewsDetail" {
if let destination = segue.destination as? NewsDetailViewController {
destination.newsLink = "whateverlink"
destination.newsTitle.text = "whatevertitle"
}
}
}
And the line: destination.newsLink = "whateverlink"
Works perfectly.
But the line: destination.newsTitle.text = "whatevertitle"
Throws a
fatal error: Unexpectedly found nil while implicitly unwrapping an
Optional value.
And I have no idea of what if going on. The same problem happens when trying to initialise the rest of the labels in the destination.
This line is the problem
destination.newsTitle.text = "whatevertitle"
don't access outlets of the destination vc as they not yet loaded send a string and assign it to the label in the destination vc
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToNewsDetail" {
if let destination = segue.destination as? NewsDetailViewController {
destination.newsLink = "whateverlink"
destination.toSend = "whatevertitle"
}
}
}
class NewsDetailViewController: UIViewController {
#IBOutlet weak var newsTitle:UILabel!
var toSend = ""
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
self.newsTitle.text = toSend
}
}
In the prepareForSegue method, the newsTitle label is still not initialised, so it is nil.
Generally, you shouldn't set the target VC's view's properties in prepareForSegue. You should declare a newsTitleText property in NewsDetailViewController:
var newsTitleText: String!
And set this property instead:
destination.newsTitleText = "whatevertitle"
Then set the newsTitle.text in viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
// Hides the navigation bar.
self.navigationController?.setNavigationBarHidden(true, animated: false)
newsTitle.text = newsTitleText
}
When the prepare(for:sender:) method is called, NewsDetailViewController has not loaded the view yet so you can't set the text on a label. What you want to do is create another property on NewsDetailViewController such as var newsTitleText: String?. Then in viewDidLoad you can call newsTitle.text = newsTitleText.
I am new to Swift and was wondering on how to pass data from ViewController to ViewController that isn’t connected by segue. I have spend 2 hours on this and still can’t figure a way to do it.
Edit: The problem that I am confused on is How to take out all the stacked ViewController expect the root ViewController while being able to pass data back to the first ViewController from ViewController3 with
'navigationController?.popToRootViewController(animated: false)'
class ViewController: UIViewController, nameDelegate {
#IBOutlet weak var label1: UILabel!
#IBOutlet weak var textfield1: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
label1.text = "Name"
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let vc2 = segue.destination as! ViewController2
vc2.middleOfTransferingName = textfield1.text!
}
#IBAction func buttonPressed1(_ sender: Any) {
performSegue(withIdentifier: "go2", sender: self)
}
func nameThatWasEntered(name: String) {
label1.text = name
}
}
class ViewController2: UIViewController, nameDelegate {
var middleOfTransferingName: String = ""
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let vc3 = segue.destination as! ViewController3
vc3.transferedWithSegueLabelText = middleOfTransferingName
vc3.namePassBack = self
}
#IBAction func buttonPressed2(_ sender: Any) {
performSegue(withIdentifier: "go3", sender: self)
}
func nameThatWasEntered(name: String) {
}
}
protocol nameDelegate {
func nameThatWasEntered(name: String)
}
class ViewController3: UIViewController {
#IBOutlet weak var label3: UILabel!
#IBOutlet weak var textfield3: UITextField!
var transferedWithSegueLabelText: String = ""
var namePassBack: nameDelegate?
override func viewDidLoad() {
super.viewDidLoad()
label3.text = transferedWithSegueLabelText
}
#IBAction func buttonPressed3(_ sender: Any) {
namePassBack!.nameThatWasEntered(name: textfield3.text!)
navigationController?.popToRootViewController(animated: false)
}
}
I found the way to transfer ViewController3 data to ViewController!
var vc3 = ViewController3()
then making ViewController as the delegate of vc3 upon loading.
override func viewDidLoad() {
super.viewDidLoad()
vc3.namePassBack = self
}
Then going back to ViewController3, I add ""vc3."" before using the delegate.
#IBAction func buttonPressed3(_ sender: Any) {
vc3.namePassBack!.nameThatWasEntered(name: textfield3.text!)
navigationController?.popToRootViewController(animated: false)
}
if you use segue then use 'Unwind segue'
for this write given code in your 'A view controller'
#IBAction func unwindToThisViewController(segue: UIStoryboardSegue) {
}
In B_viewcontroller, On press button call 'Unwind segue'.
Note:- With the help of Unwind segue you can send the value for 3ed vc to 1se vc same as you send value form 1st vc to 2nd vc
for more go to this link
I got small containerView with UILabel on main app screen. I got UIButton on main UIViewController. I want to change text of label that belongs to containerView class by clicking button in UIViewController.
I try to make it with delegation, but for some reason i got a mistake (Unwraping optional)...
I try to make it with Protocol, bud method "addText" in ContView dont works((((((
class ViewController: UIViewController {
var delegate: DelegateProtocol?
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func button(_ sender: Any) {
delegate?.addText(String2: "123")
}}
///////////////////////////////////////////////////////////////////////
protocol DelegateProtocol {
func addText(String2: String)
}
//////////////////////////////////////////////////////////////////////
class ContViewController: UIViewController, DelegateProtocol {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "con" {
let vc = segue.destination as! ViewController
vc.delegate = self
}
}
func addText(String2: String) {
label.text = String2
}
#IBOutlet weak var label: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
}
first make an global variable in your view controller
private var viewController: YourVC?
then give your container view segue an identifier and do follwing
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "yourviewcontroller Segue identifiew" { //your container view segue identifier
viewController = segue.destination as? SelectedImageVC
}
}
now you can use you viewController to access label in your containerview controller like
if let controller = viewController {
controller.yourlabel.text = "text you want"
}
I try to access a textfield content in my view profileView from my first view viewController but it doesn't work.
I read that I have to use override func prepare(for segue: UIStoryboardSegue, sender: Any?) {} so I did but it still not working and I don't understand why.
Here is my viewController code:
// This code is the code generated by xCode, only the loginField was added.
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var loginField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
and here is my profileController prepare func:
var login: String!
#IBOutlet weak var myLabel: UILabel!
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
print("prepare")
if (segue.identifier == "mainMenu")
{
let svc = segue.source as! ViewController
login = svc.loginField.text
self.myLabel.text = login
print(login)
}
}
Actually, the thing i really read was "prepareForSegue" func but when I try to override it, xCode won't compile the code...
Thanks for your help.
write your prepareforSegue method in your viewController
why?
Because you want to send ViewController textfield data to profileViewController.That is write your prepareForSegue in Source. Here,
Source = ViewController
Destination = ProfileView
Note:
Use a variable in your destinationViewController(ProfileView Controller) and keep the textField data in this variable.
like this in prepareForSegue.
destinationVC.someVariable = self.SourceViewLabel.text // your sourceViewController
and in viewDidLoad of your destinationViewController(ProfileView) write this.
self.profileLabel.text = somVariable
In my first view i wrote this.
#IBAction func nexVCAction(_ sender: Any) {
self.performSegue(withIdentifier: "secondvc", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "secondvc" {
let vc = segue.destination as! secondVC
vc.stringHolder = textField.text!
}
}
And this is the second view code.
import UIKit
class secondVC: UIViewController {
#IBOutlet weak var textlabel: UILabel!
var stringHolder:String = ""
override func viewDidLoad() {
super.viewDidLoad()
textlabel.text = stringHolder
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I made git project for this.
Check only FirstVC.swift and secondVC.swift
And this is the output.
You cannot set the text of the UITextField and any other components of UIKit in the prepare for segue, because all View components of the recently allocated controller are not initialised yet they are all nil in prepareForSegue. they allocated only be when the viewController is presented.
You set Text for current ViewController TextField at prepareForSegue. Instead of this you should set text at viewWillAppear method while pop or dismiss the presented ViewController by using Notification, Delegate or userDefaults etc...
You just need a small fix since UITextField and any other components of UIKit are not initialised yet in the prepare for segue:
var login: String!
#IBOutlet weak var myLabel: UILabel!
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
print("prepare")
if (segue.identifier == "mainMenu")
{
let svc = segue.source as! ViewController
login = svc.loginField.text
// self.myLabel.text = login
print(login)
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.myLabel.text = login
}
Data flow from one controller to another is the very popular theme for ios beginners. There are several approaches to achieve this goal: segues, delegate pattern, notifications, initialization of new instance of controller, saving data to local storage etc.
You should user prepare(for segue: sender:) method only when you have segue from you current controller to another. You can get access to destination controller instance via destination property of segue parameter.
Also never call IBOutlet properties of destination controller in prepareForSegue - it can be cause of crash, because Outlets may be uninitilized at this time. Instead use String property for example.
Here is sample code:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "mainMenu") {
if let destinationVC = segue.destination as? ViewController {
destinationVC.login = self.myLabel.text
}
}
}
Where login in destinationVC is the String variable to store login.