I have ViewController, which has a textfield and a button. The user enters his name into the textfield and hits the DONE button. When he hits the button, he is segued to GifteeDetails, which is a different view controller. There is a label in that viewController that is supposed to display his name. But, his name doesn't show up. I don't receive an error.
Here's ViewController:
#IBOutlet weak var textGifteeName: UITextField!
#IBAction func toDetails(_ sender: Any) {
performSegue(withIdentifier: "toDetails", sender: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destDetails: GifteeDetails = segue.destination as! GifteeDetails
destDetails.nametext = textGifteeName.text!
destDetails.agetext = "\(Int(age)! - 2000 + 17)"
destDetails.locationstext = labelGifteeLocationsPreview.text!
destDetails.intereststext = labelGifteeInterestsPreview.text!
}
Here's GifteeDetails:
var nametext = String()
var agetext = String()
var locationstext = String()
var intereststext = String()
#IBOutlet weak var labelGifteeName: UILabel!
#IBOutlet weak var labelGifteeAge: UILabel!
#IBOutlet weak var labelGifteeLocations: UILabel!
#IBOutlet weak var labelGifteeInterests: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
nametext = labelGifteeName.text!
agetext = labelGifteeAge.text!
locationstext = labelGifteeLocations.text!
intereststext = labelGifteeInterests.text!
}
Sorry about all the !. Swift gives me an error unless I have them.
You are updating the strings nametext and others, which are not connected to your labels.
You need to replace this piece of code:
destDetails.nametext = textGifteeName.text!
destDetails.agetext = "\(Int(age)! - 2000 + 17)"
destDetails.locationstext = labelGifteeLocationsPreview.text!
destDetails.intereststext = labelGifteeInterestsPreview.text!
With:
destDetails.labelGifteeName.text = textGifteeName.text!
destDetails.labelGifteeAge.text = "\(Int(age)! - 2000 + 17)"
destDetails.labelGifteeLocations.text = labelGifteeLocationsPreview.text!
destDetails. labelGifteeInterests.text = labelGifteeInterestsPreview.text!
nametext is a String object, and it is different from labelGifteeName.text which is the String of the label you want to update.
If you use segue then pls remove it, and then create action method of that button in the FirstviewController and use pushViewController to move on the SecondviewController.
Swift 3
Example:
#IBAction func toDetails(_ sender: Any)
{
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "SecondView") as! SecondView
UserDefaults.standard.set(self. textGifteeName.text, forKey: "savedStringKey")
UserDefaults.standard.synchronize()
self.navigationController?.pushViewController(vc,
animated: true)
}
In SecondView:
override func viewDidLoad() {
super.viewDidLoad()
self.labelGifteeName.text = UserDefaults.standard.string(forKey: "savedStringKey")!
}
Please Update your func viewDidLoad() method in GifteeDetailsVC with labelGifteeName.text! = nametext , labelGifteeAge.text!= agetext instead of your code because you have already assigned the value in to strings i.e, nametext and agetext in ViewController, you need to display string value in label
Related
import UIKit
//EventList ViewController
class EventPage: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
}
class EventForm: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
//IBOutlets
#IBOutlet weak var eventNameField: UITextField!
#IBOutlet weak var fromTimePicker: UIDatePicker!
#IBOutlet weak var toTimePicker: UIDatePicker!
#IBOutlet weak var colorPreview: UIView!
#IBAction func cancel(_ sender: Any) {
//empty text field
eventNameField.text = ""
}
#IBAction func save(_ sender: Any) {
if (eventNameField.hasText) {
//fix error handling
eventNameField.backgroundColor = UIColor.systemGray2
//pull data from fields
let text = eventNameField.text!
let fromTime = fromTimePicker.date
let toTime = toTimePicker.date
//initialize object
let currentEvent = EventModel(eventName: text, fromTime: fromTime, toTime: toTime, color: storedColor)
//append to data model
EventDataArray.append(currentEvent)
//transition
present(EventPage(), animated:true)
}
else {
eventNameField.backgroundColor = UIColor.systemRed
}
}
}
I currently have an EventPage class declared as type UIViewController, but upon pressing the save button with a populated text field a transition to a blank ViewController occurs. I've attached the class to the correct ViewController in main.storyboard.
The problem in here is that you are creating a new EventPage but it doesn't inherit from Storyboard.
1
Go to the inspector in your storyboard, select your View Controller, and write an identifier for your View Controller (can be anything)
Write it in Storyboard ID:
2
Replace
present(EventPage(), animated:true)
With
(don't forget to replace 'MYIDENTIFIER' with the id you entered earlier)
let viewController = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "MYIDENTIFIER") as! EventPage
// If you need to do any configurations to your view controller, do that in here.
// For example:
// viewController.label.text = "Hello, world!"
present(viewController, animated:true)
Note
If the name of your Storyboard file name is not called Main, replace "Main" in step 2 with the name of your storyboard file (excluding .storyboard)
Im trying to pass an player score from VC1 to a view that displays the current scores of all players(4). the display view is on a separate view controller than where the player(s) score is defined and stored.
I have done the prepare(segue) and im able to pass other variables to the display VC(ThirdViewController). but when I try to assign the player score to the uilabel.text It tells me that I have unwrapped a nil value
I have even tried to just set the label text to a static string and still get the nil error.
class ViewController: UIViewController {
var name = String()
var player1Score = 1
var player2Score = 2
var player3Score = 3
var player4Score = 4
//MARK: ********* IBOutlets **********
#IBOutlet weak var playerSegmentOutlet: UISegmentedControl!
#IBOutlet weak var diceSegmentOutlet: UISegmentedControl!
#IBOutlet weak var targetScoreSliderOutlet: UISlider!
#IBOutlet weak var matchTargetSwitchOutlet: UISwitch!
#IBOutlet weak var targetScoreLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let VC = segue.destination as? SecondViewController {
VC.player1CurrentScore = player1Score
VC.player2CurrentScore = player2Score
VC.player3CurrentScore = player3Score
VC.player4CurrentScore = player4Score
}
}
Second view Controller
class SecondViewController: UIViewController {
#IBOutlet weak var CurrentRoundScoreLabel: UILabel!
#IBOutlet weak var CurrentPlayerScoreLabel: UILabel!
var player1CurrentScore = 1
var player2CurrentScore = 1
var player3CurrentScore = 1
var player4CurrentScore = 1
override func viewDidLoad() {
super.viewDidLoad()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let VC = segue.destination as? ThirdViewController {
VC.player1ScoreLabel.text = String(player1CurrentScore)
VC.player2ScoreLabel.text = String(player2CurrentScore)
VC.player3ScoreLabel.text = String(player3CurrentScore)
VC.player4ScoreLabel.text = String(player4CurrentScore)
}
}
Third View Controller
class ThirdViewController: UIViewController {
#IBOutlet var player1ScoreLabel: UILabel!
#IBOutlet var player2ScoreLabel: UILabel!
#IBOutlet var player3ScoreLabel: UILabel!
#IBOutlet var player4ScoreLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
}
no matter what I try to do with with UILabel.text it shows up as nil
I'm totally frustrated and I'm sure I am missing something simple because of my frustration, please someone help me.
This is an inefficient way to do this as you are passing data through 3 different objects. However, going on with this methodology, the problem is the label's are not created yet inside
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let VC = segue.destination as? ThirdViewController {
VC.player1ScoreLabel.text = String(player1CurrentScore)
VC.player2ScoreLabel.text = String(player2CurrentScore)
VC.player3ScoreLabel.text = String(player3CurrentScore)
VC.player4ScoreLabel.text = String(player4CurrentScore)
}
}
See, the label isn't created yet. So, you are setting text on aUILabel that isn't initialized. Therefore, you need to create variables for the labels inside ThirdViewController.
Third View Controller
class ThirdViewController: UIViewController {
#IBOutlet var player1ScoreLabel: UILabel!
#IBOutlet var player2ScoreLabel: UILabel!
#IBOutlet var player3ScoreLabel: UILabel!
#IBOutlet var player4ScoreLabel: UILabel!
var score0:Int!
var score1:Int!
var score2:Int!
var score3:Int!
override func viewDidLoad() {
super.viewDidLoad()
self.player1ScoreLabel.text = String(score0)
self.player2ScoreLabel.text = String(score1)
self.player3ScoreLabel.text = String(score2)
self.player4ScoreLabel.text = String(score3)
}
}
and change the segue in SecondViewController
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let VC = segue.destination as? ThirdViewController {
VC.score0 = player1CurrentScore
VC.score1 = player2CurrentScore
VC.score2 = player3CurrentScore
VC.score3 = player4CurrentScore
}
}
Another Way:
Let's create a singleton called Game. Within this (assuming you only have 4 players) we can create 4 players that will never change. This allows us to create instances of players in one location and call upon them as necessary.
NOTE: A singleton can be misused EASILY.
https://cocoacasts.com/what-is-a-singleton-and-how-to-create-one-in-swift
https://cocoacasts.com/are-singletons-bad/
class Game {
static var score0:Int = 0
static var score1:Int = 0
static var score2:Int = 0
static var score2:Int = 0
}
Then, anywhere in your code you can access Game.score0, Game.score1.
CAUTION:
I would caution you to very carefully use singletons. You don't want everything with public access. You need to determine if this is good for you or not. Cheers.
As a title I need to pass data from a JSON to my Home class, but between the two classes there is a navigation controller
Then I would like to know how to pass data through it. Thanks to everyone for the advice.
Storyboard. Login Class:
let title = list["title"] as! String
let description = list["tagline"] as! String
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let navVC = segue.destination as! UINavigationController
let tableVC = navVC.viewControllers.first as! Home
tableVC.title = "Test"
tableVC.description = "Test"
}
Home Controller:
#IBOutlet weak var titleActivity: UILabel!
#IBOutlet weak var descriptionActivity: UILabel!
var description = ""
var title = ""
override func viewDidLoad() {
super.viewDidLoad()
titleActivity.text = nome //NIL
descriptionActivity.text = descrizione //NIL
}
My custom cell has a button that when clicked, the user can be taken to another ViewControler. That button has a titleLabel with the String of a user id. What I want to do is take the user to a new UIViewController, passing that clicked buttons's titleLabel (user id) to a variable on the new View Controller. That way, I can use that variable (user id) get further information from firebase and display it on the UI View controller.
on the .xib of the custom cell, I print the UID to make sure each button prints with the correspondent ID, which it does. I can't figure out a way to pass that ID to a new ViewController.
I tried researching online and I found out you can't do prepare(for segue) or performsegue(WithIdentifier) on a customCell.xib.
I tried doing delegates and then protocols but still couldn't get it to work. I am new with Swift. Any help would be great, thank you!
This is the customCell.Xib's Swift file:
class CustomCellTableViewCell: UITableViewCell {
#IBOutlet weak var postImage: UIImageView!
#IBOutlet weak var nameLbl: UILabel!
#IBOutlet weak var descriptionLbl: UITextView!
#IBOutlet weak var profileImageBtn: UIButton!
#IBOutlet weak var profileImage: UIImageView!
#IBOutlet weak var view: UIView!
var btnSelected : Bool = false
var vcInstance: ProfilesTableVC?
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
view.clipsToBounds = true
view.layer.cornerRadius = view.frame.size.width / 2
profileImage.layer.cornerRadius = profileImage.frame.size.width / 2
descriptionLbl.alpha = 0.7
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
}
#IBAction func profileBtnPressed(_ sender: Any) {
let passValue = UserProfileVC()
let profileTvC = ProfilesTableVC()
print (profileImageBtn.titleLabel!.text!)
var id = (profileImageBtn.titleLabel!.text!)
profileTvC.didSelectProfileBtn(senderID: id)
}
This is the tableViewController, where I everything gets loaded (not where I want to pass the value). I tried passing the value here and then do a prepareForSegue to pass the value to the new UIViewController but the value becomes nil after the segue happens. I am just including code where the .xib call the function from the table view.
class ProfilesTableVC: UIViewController, UITableViewDelegate, UITableViewDataSource, UITextFieldDelegate,UINavigationControllerDelegate, UIImagePickerControllerDelegate{
let cell = CustomCellTableViewCell()
func didSelectProfileBtn(senderID: String) {
senderIDArray.append(senderID)
var index = senderIDArray.count - 1
selectedCellUserID = senderIDArray[index]
performSegue(withIdentifier: "showSendersProfile", sender: Any?.self)
}
This is the UIViewController where I want to pass the variable and display further information from Firebase using that ID
import UIKit
import Firebase
class UserProfileVC: UIViewController {
let customCell = CustomCellTableViewCell()
let profileTvC = ProfilesTableVC()
#IBOutlet weak var profileImage: UIImageView!
#IBOutlet weak var nameLbl: UILabel!
var delegate : Any?
var getName = String()
var getsenderID = String()
let userDataRef = Database.database().reference().child("Users")
override func viewDidLoad() {
super.viewDidLoad()
print("ID is: \(profileTvC.selectedCellUserID)")
let sender = getsenderID
print(sender)
}
}
If you don't want to use protocols, you can addTarget to the button in the tableView - cellForRowAt method, also in that method you set the tag to the row index value.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let profileCell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier) as! MoviewReviewCell
reviewCell.profileImageBtn.tag = indexPath.row
reviewCell.profileImageBtn.addTarget(self, action: #selector(tappedOnXibCellButton), for: .touchUpInside)
return reviewCell
}
#objc func tappedOnXibCellButton(sender: UIButton) {
print(sender.tag)
performSegue(withIdentifier: reviewListToDetails, sender: sender.tag)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let identifier = segue.identifier
if identifier == "segueName" {
let destViewController = segue.destination as! DestinationClassViewController
let selectedIndex = sender as! Int
let profileId = profilesList[selectedIndex].id
destViewController.profileId = profileId
}
}
You seem to create a NEW ProfilesTableVC, and try to perform the segue on. The newly created one is not on your view stack, and not from your storyboard.
You could add this while returned cellForRowAt (at the ProfilesTableVC of course):
cell.vcInstance = self
Then in the button click
#IBAction func profileBtnPressed(_ sender: Any) {
print (profileImageBtn.titleLabel!.text!)
var id = (profileImageBtn.titleLabel!.text!)
vcInstance?.didSelectProfileBtn(senderID: id)
}
You can do it with protocols/delegates. I think you tried but there is something wrong with your trial.
Define a callback delegate:
protocol CustomCellDelegate: AnyObject {
func customCell(didSelectButton name: String)
}
You will notice extending AnyObject. This is to allow weak references, try to read about Swift ARC
Then, in your cell:
weak var delegate: CustomCellDelegate?
Then in the profileBtnPressed(_ sender: Any)
#IBAction func profileBtnPressed(_ sender: Any) {
var id = (profileImageBtn.titleLabel!.text!)
delegate?.customCell(didSelectButton: id)
}
When dequeing the cell:
(cell as? CustomCellTableViewCell)?.delegate = self
I am beginner in swift and working on one project where I am using collectionView. From collectionView, I want to transfer some values to details view but I am getting the above mentioned error. Values are not nil but somehow, it is giving this error while performing segue. Anybody help me, I am badly stuck here.
//In my CollectionView Controller.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if(segue.identifier == "DetailsView")
{
if let vc:DetailsViewController = segue.destinationViewController as? DetailsViewController
{
vc.details.text = self.description
vc.line.text = self.subText
vc.startTime.text = self.formatted_time
}
}
}
//DetailsViewController
import UIKit
class DetailsViewController: UIViewController {
#IBOutlet var startTime: UILabel!
#IBOutlet var line: UILabel!
#IBOutlet var details: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
This basically means your IBOutlets are not yet initialised.
You should set strings and then in the viewDidLoad set you labels.
So to sum up:
Add string properties in your DetailsViewController
Set these string properties in your preparForsegue function
in the viewDidLoad of your DetailsViewController, set your labels
Your code should look like something like this :
//In my CollectionView Controller.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if(segue.identifier == "DetailsView")
{
if let vc:DetailsViewController = segue.destinationViewController as? DetailsViewController
{
vc.detailsString = self.description
vc.lineString = self.subText
vc.startTimeString = self.formatted_time
}
}
}
//DetailsViewController
import UIKit
class DetailsViewController: UIViewController {
#IBOutlet var startTime: UILabel!
#IBOutlet var line: UILabel!
#IBOutlet var details: UILabel!
var startTimeString: String?
var lineString: String?
var detailsString: String?
override func viewDidLoad() {
super.viewDidLoad()
startTime.text = tmpStartTimeString
line.text = tmpLineString
details.text = tmpDetailsString
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
}
Double check my code, I've wrote it very quickly ;)
The IBOutlets in a destination view controller aren't set until some time after prepareForSegue finishes
In DetailsViewController, add three instance variables:
var startTime: String?
var line: String?
var details: String?
Then in prepareForSegue, set those three values:
vc.details = self.description
vc.line = self.subText
vc.startTime = self.formatted_time
Then in viewDidLoad of DetailsViewController
detailsLabel.text = self.details
lineLabel.text = self.line
startTimeLabel.text = self.startTime
As the two answer above are point out when you create an instance of a UIViewController like for example in the prepareForSegue when you call segue.destinationViewController as? DetailsViewController this not mean that the #IBOutlet's are injected or initialized yet. The #IBOutlet's are initialized when the view is fully loaded, so you can do two of the following options:
Create variables in your UIViewController in which you can save the values after the init of the UIViewController in the prepareForSegue and then in the viewDidLoad() of the another UIViewController you set the values for the #IBOutlet's.
Another option is call the view (e.g let _ = vc.view) property when you create the instance of the UIViewController, in this way you can force the view to load load fully and you can set your #IBOutlet's from the prepareForSegue.
I hope this help you.