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
}
Related
I'm trying to create the feature where when a user clicks on a specific cell in my UITableView, the Project will segue to a new ViewController and show all the information that has been saved in the CoreData. The Problem is that when I touch on a cell I get an error of
Unexpected nil while unwrapping optional value
Here is my code as it is right now within the ViewController that has the TableView
class ContactViewController: UIViewController, UITableViewDataSource, NSFetchedResultsControllerDelegate, UITableViewDelegate {
var selectName:String?
var selectPhone:String?
var selectComment:String?
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
selectName = contact[indexPath.row].name
selectPhone = contact[indexPath.row].phone
selectComment = contact[indexPath.row].comments
performSegue(withIdentifier: "MySegue", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "MySegue"{
if let destVC = segue.destination as? IndiViewController {
destVC.NameLabel = selectName
destVC.PhoneLabel = selectPhone
destVC.CommentLabel = selectComment
}
}
}
This is my code in IndiViewController (the VC in which I want the user to view the contact)
class IndiViewController: UIViewController {
#IBOutlet var NameLabel: UILabel!
#IBOutlet var PhoneLabel: UILabel!
#IBOutlet var CommentsLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
}
}
I've tried a few other methods but all still delivered the same error
I troubleshooted a bit to see which variable truly was causing the nil by doing this:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "MySegue"{
if let destVC = segue.destination as? IndiViewController {
destVC.NameLabel = "selectName" //I thought if perhaps the nil was the var selectName this would at least let me know
}
}
However even through this, the app crashes and gives the same error. So I think the issue is with the Labels in the IndiViewController.
So I tried creating an empty String and assigning it to NameLabel like this:
class IndiViewController: UIViewController {
#IBOutlet var NameLabel: UILabel!
var name = ""
override func viewDidLoad() {
super.viewDidLoad()
NameLabel.text = name
}
}
but still no luck.
What am I doing wrong?
Yet it can be an IBOutlet error, even for typo.
delete #IBOutlet var NameLabel: UILabel!
remove the link in the StoryBoard "referencing outlets" tab
click-drag a new outlet for the UILabel and do not name it with a capital letter
// #IBOutlet var NameLabel: UILabel!
#IBOutlet var nameLabel: UILabel!
Edit
Also try to pass your informations in two times :
create a new var in your destinationViewController like :
class IndiViewController: UIViewController {
#IBOutlet var nameLabel: UILabel!
var myText: String = ""
override func viewDidLoad() {
super.viewDidLoad()
nameLabel.text = myText // assign the var to the labels text
}
}
In your prepareForSegue method assign myText and not the nameLabel.text
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "MySegue"{
if let destVC = segue.destination as? IndiViewController {
destVC.myText = "selectName"
}
}
}
my guess is that you cant acces IBOutlets in prepare(for segue:) method. The destination ViewController is not built yet
I am using the prepareforsegue function to transfer data between view controllers. I am attempting to transfer the data held by 5 variables yet only 4 transfer. I am wondering if it is a formatting issue considering the 4 that transfer correctly have different variable types to the other. Any help would be greatly appreciated. Thank you for your time.
Sender View Controller
import Foundation
import UIKit
class CratesViewController : UIViewController {
var unlockedAK47 = "false"
var unlockedDesertEagle = "false"
var unlockedGlock17 = "false"
var unlockedGlock18 = "false"
var coinsAmount = 0
let screenSize: CGRect = UIScreen.main.bounds
#IBOutlet weak var coins: UILabel!
#IBOutlet weak var cratesImageView: UIImageView!
#IBOutlet weak var unlockView: UIView!
#IBOutlet weak var backButtonOutlet: UIButton!
#IBOutlet weak var gunImageView: UIImageView!
#IBOutlet weak var imageView: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
coins.text = String(coinsAmount)
gunImageView.isHidden = true
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "cratesToMainSegue" {
let destViewController = segue.destination as! ViewController
destViewController.unlockedAK47 = unlockedAK47
destViewController.unlockedDesertEagle = unlockedDesertEagle
destViewController.unlockedGlock17 = unlockedGlock17
destViewController.unlockedGlock18 = unlockedGlock18
destViewController.coinsAmount = coinsAmount
}
}
}
Destination View Controller
import UIKit
class ViewController: UIViewController {
var unlockedAK47 = "false"
var unlockedDesertEagle = "false"
var unlockedGlock17 = "true"
var unlockedGlock18 = "false"
struct defaultsKeys {
static let keyOne = ""
}
var coinsAmount = 100
#IBOutlet weak var coinsAmountLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Getting
let defaults = UserDefaults.standard
if let stringOne = defaults.string(forKey: defaultsKeys.keyOne) {
coinsAmount = Int(stringOne)!
}
coinsAmountLabel.text = String(coinsAmount)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Note that the segue identifiers have been set in the interface builder
if segue.identifier == "cratesSegue" {
let destViewController = segue.destination as! CratesViewController
destViewController.coinsAmount = coinsAmount
destViewController.unlockedAK47 = unlockedAK47
destViewController.unlockedDesertEagle = unlockedDesertEagle
destViewController.unlockedGlock17 = unlockedGlock17
destViewController.unlockedGlock18 = unlockedGlock18
} else if segue.identifier == "collectionSegue" {
let destViewController = segue.destination as! CollectionViewController
destViewController.coinsAmount = coinsAmount
destViewController.unlockedAK47 = unlockedAK47
destViewController.unlockedDesertEagle = unlockedDesertEagle
destViewController.unlockedGlock17 = unlockedGlock17
destViewController.unlockedGlock18 = unlockedGlock18
}
}
#IBAction func saveButton(_ sender: Any) {
coinsAmount = coinsAmount + 10
coinsAmountLabel.text = String(coinsAmount)
// Saving
let defaults = UserDefaults.standard
defaults.set(String(coinsAmount), forKey: defaultsKeys.keyOne)
}
}
Please let me know if any more information is needed. :)
This is not because coinsAmount is a different type. This is because coinsAmount's value is overwritten in viewDidLoad:
let defaults = UserDefaults.standard
if let stringOne = defaults.string(forKey: defaultsKeys.keyOne) {
coinsAmount = Int(stringOne)! <<<< HERE!
}
I think what you want to do is to get the coins amount only if it is not passed to ViewController.
You should declare coinsAmount as an optional:
var coinsAmount: Int!
And check whether it is nil before overwriting it, so that you don't accidentally overwrite the passed value.
if coinsAmount == nil {
let defaults = UserDefaults.standard
if let stringOne = defaults.string(forKey: defaultsKeys.keyOne) {
coinsAmount = Int(stringOne)!
}
}
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
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.
I have two view. On my first view i create some data and send to other view lets name view2. So my view1 has code:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "showUserDetail" {
(segue.destinationViewController as! UserDetailTableViewController).detailContact = detailCoversationContact
}
}
In my detailCoversationContact i have detail about this one user, this detail like number, nick etc. Now as i expect this data are put to variable detailContact in my view2
And this is my cod in view2 this code is work:
class UserDetailTableViewController: UITableViewController {
#IBOutlet weak var nickNameLabel: UILabel!
var nickMy: String = ""
var detailContact: AnyObject? {
didSet {
// Update the user interface for the detail item.
if let detail = self.detailContact {
self.nickMy = (detail.valueForKey("nickName") as? String)!
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
nickNameLabel.text = nickMy
}
}
When i send data to detailContact' i check is didSet if yes i set my nickMy and this is work. But what is first ? setting my var or viewDidLoad?
this is my code and not working and can someone explain why ?
class UserDetailTableViewController: UITableViewController {
#IBOutlet weak var nickNameLabel: UILabel!
var detailContact: AnyObject? {
didSet {
// Update the user interface for the detail item.
if let detail = self.detailContact {
self.title = detail.valueForKey("nickName") as? String
self.nickNameLabel?.text = (detail.valueForKey("nickName") as? String)!
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
}
Ok this is self.title and work i see the name of user but title is from tableView. But my nickNameLabel is not change ? why ?
At the time of prepareForSegue, the IBOutlets have not been set up yet. So, self.nickNameLabel is still nil, and optional chaining makes self.nickNameLabel?.text = ... safely do nothing.
Set the value in viewDidLoad() when the IBOutlets have been set up:
override func viewDidLoad() {
super.viewDidLoad()
self.nickNameLabel?.text = (detail.valueForKey("nickName") as? String)!
}
Alternatively, you can trigger didSet by setting the detailContact to itself in viewDidLoad(). You have to trick Swift in order to do this because it thinks assigning detailContact to itself does nothing:
override func viewDidLoad() {
super.viewDidLoad()
detailContact = (detailContact) // trigger didSet to set up the label
}