I am trying to pass a news ID of type string to the second VC and load the object based on it from Realm. When I debugged, I found that the prepare for segue is correctly setting the detailNewsVC.newsID to the primary key of my news item but the second VC is not receiving it. Any help on this?
Checks I have made:
Made sure that the detail VC identifier is correct
detailNewsVC.newsID in VC 1 is correctly setting the news ID .. This is to make sure that realm is correctly sending the newsID and it is working fine.
Changed the viewDidLoad in VC 2 to viewWillLoad..Just to make sure that second vc is not loaded before for any reason but no luck on that.
Restarted xcode
Replaced newsID in VC 2 with an actual news primary key and it's correctly pulling the related news. I think the culprit is that the VC2 property: newsID is not updating when prepare for segue is called.
First VC code for prep for segue:
extension HomeVC: UICollectionViewDelegate {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == SegueIdentifier.gotodetail.rawValue, let sendNewsID = sender as? String {
let navVC = segue.destination as? UINavigationController
let detailNewsVC = navVC?.viewControllers.first as! DetailNewsVC
detailNewsVC.newsID = sendNewsID
print("Detail News ID = \(detailNewsVC.newsID)")
}
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let newsID = newsArray[indexPath.row].newsId
performSegue(withIdentifier: SegueIdentifier.gotodetail.rawValue, sender: newsID)
}
}
Second VC Code:
class DetailNewsVC: UIViewController {
#IBOutlet private weak var scrollView: UIScrollView!
#IBOutlet private weak var newsTitle: UILabel!
#IBOutlet private weak var newsImage: UIImageView!
#IBOutlet private weak var newsDescription: UILabel!
var newsID = ""
override func viewDidLoad() {
super.viewDidLoad()
let realm = try! Realm()
print("News ID: \(newsID)")
guard let news = realm.object(ofType: News.self, forPrimaryKey: newsID as AnyObject) else {
print("Cannot load news")
return
}
print(news)
newsTitle.text = news.newsTitle
if let url = URL(string: news.urlToImage), let data = try? Data.init(contentsOf: url) {
newsImage.image = UIImage(data: data)
}
newsDescription.text = news.newsDescription
}
}
Move your prepare function out of the extension and put it in HomeVC. According to Apple's Swift Guide extensions cannot override existing functionality.
Extensions can add new functionality to a type, but they cannot override existing functionality.
Apple Developer Guide
It's hard to tell in which order UIKit calls the UIViewController methods, but it might be possible that viewDidLoad is getting called before you get the chance to set the value of newsID.
The following might be overkill, but it'll guarantee the views will be updated during viewDidLoad, or otherwise if newsID is set after the fact:
class DetailNewsVC: UIViewController {
#IBOutlet private weak var scrollView: UIScrollView!
#IBOutlet private weak var newsTitle: UILabel!
#IBOutlet private weak var newsImage: UIImageView!
#IBOutlet private weak var newsDescription: UILabel!
public var newsID = "" {
didSet {
updateUIForNews()
}
}
override func viewDidLoad() {
super.viewDidLoad()
updateUIForNews()
}
private func updateUIForNews() {
guard !newsID.isEmpty else {
return
}
let realm = try! Realm()
print("News ID: \(newsID)")
guard let news = realm.object(ofType: News.self, forPrimaryKey: newsID as AnyObject) else {
print("Cannot load news")
return
}
print(news)
newsTitle.text = news.newsTitle
if let url = URL(string: news.urlToImage), let data = try? Data.init(contentsOf: url) {
newsImage.image = UIImage(data: data)
}
newsDescription.text = news.newsDescription
}
}
Related
I'm trying to make a leaderboard for a word scrambler app so I am saving the data before segueing to the next view controller which will eventually be a leaderboard. My outlets are all connected and the segue identifier was written correctly so I don't see why the app crashes after done is pressed
the error line occurs here: class AppDelegate: UIResponder, UIApplicationDelegate {
var finalScore = Int()
var playerName = String()
var allMyStoredData = UserDefaults.standard
class secondVC: UIViewController {
#IBOutlet weak var scoreLabel: UILabel!
#IBOutlet weak var nameTF: UITextField!
#IBOutlet weak var doneButton: UIButton!
var playerScore = 0
override func viewDidLoad() {
super.viewDidLoad()
scoreLabel.text = "Your score is: \(finalScore)"
loadData()
}
#IBAction func donePressed(_ sender: Any) {
saveData()
//this part won't execute
performSegue(withIdentifier: "toLeaderboard", sender: self)
}
func saveData () {
playerName = nameTF.text!
playerScore = finalScore
allMyStoredData.set(playerName, forKey: "saveTheName")
allMyStoredData.set(playerScore, forKey: "saveTheScore")
}
func loadData () {
if let loadPlayerName:String = UserDefaults.standard.value(forKey: "saveTheName") as? String {
playerName = loadPlayerName
}
if let loadTheScore:Int = UserDefaults.standard.value(forKey: "saveTheName") as? Int {
playerScore = loadTheScore
}
}
}
Update: there was an outlet in the view controller the segue "toLeaderboard" goes to which wasn't connected or used so I deleted it and now the code is fine
I have been working on this issue for two days now and sadly I cannot figure out the issue to my problem. I'm trying to take one item from my initial one time view controller and send that to my main view controller where it will be saved within the main view controller and will appear upon that controller when reloading the app.
Here is my app delegate code for the "first time" view controller
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {
if UserDefaults.standard.bool(forKey: "firstTimer") {
let storyBoard = UIStoryboard.init(name: "Main", bundle: nil)
let mainView = storyBoard.instantiateViewController(withIdentifier: "MainViewControllerID")
let nav = UINavigationController(rootViewController: mainView)
nav.navigationBar.isHidden = true
self.window?.rootViewController = nav
}
return true
}
containers and saveContext are default
import UIKit
import CoreData
class FirstTimeViewController: UIViewController {
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
private var appDelegate = UIApplication.shared.delegate as! AppDelegate
private var player = [Player]()
#IBOutlet weak var nameTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
// This View Controller will only be used once upon the first time the app is being used.
// MARK: Make func that prepares for segue on initial opening of app
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toMainViewController" {
let mainViewController = segue.destination as! UINavigationController
let destination = mainViewController.topViewController as! MainViewController
if let newPlayer = self.nameTextField.text{
destination.name.name = newPlayer
destination.playerData.name = newPlayer
saveItems()
}
}
}
#IBAction func continueButtonPressed(_ sender: UIStoryboardSegue) {
UserDefaults.standard.set(true, forKey: "firstTimer")
let mainPlayer = PlayerData()
let player1 = Player(entity: Player.entity(), insertInto: context)
player1.name = mainPlayer.name
performSegue(withIdentifier: "toMainViewController", sender: self)
saveItems()
}
func saveItems() {
do {
try context.save()
print("File Successfully saved!")
}catch {
print("Error saving Context \(error)")
}
}
// MARK: Function to Save and Load data??
/*
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destination.
// Pass the selected object to the new view controller.
}
*/
func loadItems() {
let request = Player.fetchRequest() as NSFetchRequest<Player>
do {
player = try context.fetch(request)
print("Info loaded")
} catch {
print("Error fetching data from context \(error)")
}
}
}
MainViewController being sent the information. I only want to send one item and save it to that main view controller.
import UIKit
import Foundation
import CoreData
class MainViewController: UIViewController {
//set up model object, buttons, and labels
// let player: Player!
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
private var appDelegate = UIApplication.shared.delegate as! AppDelegate
// lazy var nameText = Player(context: context)
// var playerInfo = [Player]()
lazy var player = [Player]()
let playerData = PlayerData()
var name = ""
#IBOutlet weak var playerName: UILabel!
#IBOutlet weak var currentLevel: UILabel!
#IBOutlet weak var xpCounter: UILabel!
#IBOutlet weak var playerProfileImage: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
// loadItems()
// name = playerData.name
if let nameOfPlayer = name.name {
print("This is what we see: \(nameOfPlayer)")
playerName.text = nameOfPlayer
}
appDelegate.saveContext()
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// loadView()
}
#IBAction func menuButtonPressed(_ sender: Any) {
}
func loadItems() {
let request = Player.fetchRequest() as NSFetchRequest<Player>
do {
player = try context.fetch(request)
print("Info loaded")
} catch {
print("Error fetching data from context \(error)")
}
}
// MARK : Add Name to Main View
// MARK : Add Xp To Main View
// MARK : Add UI Image to profile image view
// MARK: (Optional) Create a 'Choose a task button to segue to the task tab'
// MARK: Program the Progress Bar to update on xp gained and reset on level up
// MARK: Function to Save and Load data??
}
If dataSource code needed I will add upon request.
Thanks!
Code is wrong. You should do more check
This is what I was able to achieve:
import UIKit
import CoreData
class FirstTimeViewController: UIViewController {
private var player = [Player]()
private var appDelegate = UIApplication.shared.delegate as! AppDelegate
private let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
#IBOutlet weak var nameTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
// This View Controller will only be used once upon the first time the app is being used.
// MARK: Make func that prepares for segue on initial opening of app
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "toMainViewController" {
let entity = NSEntityDescription.entity(forEntityName: "Player", in: context)
let newPlayer = NSManagedObject(entity: entity!, insertInto: context)
if let newUser = self.nameTextField.text{
newPlayer.setValue(newUser, forKey: "name")
print("This is what i got: ", newPlayer)
}
appDelegate.saveContext()
}
}
#IBAction func continueButtonPressed(_ sender: UIStoryboardSegue) {
UserDefaults.standard.set(true, forKey: "firstTimer")
performSegue(withIdentifier: "toMainViewController", sender: self)
}
And for the Main View Controller:
import UIKit
import Foundation
import CoreData
class MainViewController: UIViewController {
//set up model object, buttons, and labels
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
private var appDelegate = UIApplication.shared.delegate as! AppDelegate
lazy var player = [Player]()
#IBOutlet weak var playerName: UILabel!
#IBOutlet weak var currentLevel: UILabel!
#IBOutlet weak var xpCounter: UILabel!
#IBOutlet weak var playerProfileImage: UIImageView!
override func viewDidLoad() {
super.viewDidLoad()
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Player")
// request.predicate = NSPredicate(format: "name = %#", "noon")
request.returnsObjectsAsFaults = false
do {
let result = try context.fetch(request)
for data in result as! [NSManagedObject] {
print(data.value(forKey: "name") as! String)
self.playerName.text = data.value(forKey: "name") as? String
}
} catch {
print("Failed")
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
// loadView()
}
#IBAction func menuButtonPressed(_ sender: Any) {
}
I'm following a very simple swift course and while everything works for the instructor the same code does not execute on my side and I'm trying to understand why is that happening.
The app is very simple, is consists of adding tasks to a TableView with a name and a switch to determine if those are important (in which case an emoji is added to the name)
While trying to access and modify the "name" attribute of my "Taskentity" core data entity, the editor gives me the error "Value of type "Taskentity" has no member "name"".
The code is the following :
import UIKit
class AddTaskViewController: UIViewController {
#IBOutlet weak var textField: UITextField!
#IBOutlet weak var isImp: UISwitch!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBAction func btnTapped(_ sender: Any) {
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
let task = Taskentity(context: context)
task.name = textField.text! // **!error!**
task.isImportant = isImp.isOn
(UIApplication.shared.delegate as! AppDelegate).saveContext()
navigationController!.popViewController(animated: true)
}
}
And my Core Data file looks like this :
Thanks for any help!
Your screen shot shows the problem perfectly. You have named the attribute corename, not name. So naturally the name name is not its name!
You have a problem with you attributes. The one titled 'corename' which is a string should be renamed to 'name' Xcode cannot tell what .name means because you have nothing that Devi gets what it is.
I have attached how your code should look to fix this problem:
import UIKit
class AddTaskViewController: UIViewController {
#IBOutlet weak var textField: UITextField!
#IBOutlet weak var isImp: UISwitch!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
#IBAction func btnTapped(_ sender: Any) {
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
let task = Taskentity(context: context)
task.corename = textField.text! // **!error!**
task.isImportant = isImp.isOn
(UIApplication.shared.delegate as! AppDelegate).saveContext()
navigationController!.popViewController(animated: true)
}
}
In my app I am using segue to pass data between two viewcontrollers and that should be easy enough, but for som reason I can`t see there I keep getting "Unresolved Identifier"
Her are some of the code that has to do with that function.
from ViewController 1
import UIKit
import CoreData
class ViewController: UIViewController, UITextFieldDelegate
{
#IBOutlet var panelWidthTextField: UITextField!
#IBOutlet var panelHightTextField: UITextField!
#IBOutlet var panelsWideTextField: UITextField!
#IBOutlet var panelsHightTextField: UITextField!
#IBOutlet var panelPitchTextField: UITextField!
#IBOutlet var calculateButton: UIButton!
#IBOutlet var resultWithLabel: UILabel!
#IBOutlet var resultHightLabel: UILabel!
#IBOutlet var fillAllFieldsLabel: UILabel!
var pawidth:String!
var pahight:String!
var papitch:String!
override func viewDidLoad()
{
super.viewDidLoad()
panelWidthTextField.text = pawidth
panelHightTextField.text = pahight
panelPitchTextField.text = pap itch
From Second ViewController
import UIKit
import CoreData
class DataBase: UIViewController, UITextFieldDelegate
{
#IBOutlet var makerTextField: UITextField!
#IBOutlet var modelTextField: UITextField!
#IBOutlet var stPanelWidthTextField: UITextField!
#IBOutlet var stPanelHightTextField: UITextField!
#IBOutlet var stPitchTextField: UITextField!
let moc = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext
// Removes keyboard when touch outside edit field.
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?)
{
view.endEditing(true)
super.touchesBegan(touches, withEvent: event)
}
#IBAction func saveButton(sender: UIButton)
{
let ed = NSEntityDescription.entityForName("Ledinfo", inManagedObjectContext: moc)
let model = Ledinfo(entity:ed!, insertIntoManagedObjectContext:moc)
model.manufactor = makerTextField.text
model.model = modelTextField.text
model.panelwidth = stPanelWidthTextField.text
model.panelhight = stPanelHightTextField.text
model.pitch = stPitchTextField.text
do {
try moc.save()
makerTextField.text = ""
modelTextField.text = ""
stPanelWidthTextField.text = ""
stPanelHightTextField.text = ""
stPitchTextField.text = ""
Alert.show("Succsess", message: "Your Record Is Saved", vc: self)
}
catch _ as NSError
{
Alert.show("Failed", message: "Something Went Wrong", vc: self)
}
}
#IBAction func searchButton(sender: UIButton)
{
let ed = NSEntityDescription.entityForName("Ledinfo", inManagedObjectContext: moc)
let req = NSFetchRequest()
req.entity = ed
let cond = NSPredicate(format: "manufactor = %#", makerTextField.text!)
req.predicate = cond
do {
let result = try moc.executeFetchRequest(req)
if result.count > 0
{
let model = result[0] as! Ledinfo
makerTextField.text = model.manufactor
modelTextField.text = model.model
stPanelWidthTextField.text = model.panelwidth
stPanelHightTextField.text = model.panelhight
stPitchTextField.text = model.pitch
} else
{
Alert.show("Failed", message: "No Record Is Found", vc: self)
}
} catch _ as NSError!
{
Alert.show("Failed", message: "No Record Is Found" , vc: self)
}
}
#IBAction func transfereButton(sender: UIButton) {
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if (segue.identifier == "transfereButton") {
let svc = segue.destinationViewController as! ViewController
svc.pawidth = stPanelWidthTextField.text
svc.pahight = stPanelHightTextField.text
svc.papitch = stPitchTextField.text
}
}
}
It can not find panelWidthTextField.text, panelHightTextField.text and panelPitchTextField.text as identifier.
I have check spelling and just can`t seem to be able to find what is missing.
Any help is appreciated
"Segue" means, that in "prepareForSegue" method you set the property of ViewController to some data in your DataBase controller. In your example, this can be done like this:
svc.pawidth = someDataFromDataBaseWhichYouWantToPassToSecondVC
svc.pahight = someDataFromDataBaseWhichYouWantToPassToSecondVC
svc.papitch = someDataFromDataBaseWhichYouWantToPassToSecondVC
And then, you can manipulate this data from your ViewController class.
You mistake that you are not passing the data from one VC to another, instead of that you are trying to set the property of 1stVC to another property of 1stVC, and there is no segue needed.
This has nothing to do with segues. do you have 3 text fields in your DataBase class with names panelWidthTextField, panelHightTextField and panelPithcTextField? It's complaining about not being able to find those variables.
You should call the performSegueWithIdentifier("transfereButton", sender: nil) inside your transfereButton IBOutlet action to actually make the prepareForSegue to run.
I have created a prepareForSegue method and I am trying to call it from a button that I created by using the performSegueWithIdentifier method. The app is crashing when I load the simulator and it's not getting me a complete error message. Can someone please lead me in the right direction?
import Foundation
import UIKit
import Alamofire
import FBSDKCoreKit
import FBSDKShareKit
import FBSDKLoginKit
class PageContentViewController: UIViewController {
#IBOutlet weak var logoImageView: UIImageView!
#IBOutlet weak var contentLabel: UILabel!
#IBOutlet weak var backgroundImageView: UIImageView!
#IBOutlet weak var pageControl: UIPageControl!
#IBOutlet weak var facebookButton: UIButton!
var index : Int = 0
var logoFile: String = ""
var content: String = ""
var backgroundFile: String = ""
let facebookReadPermissions = ["public_profile", "email", "user_friends"]
override func viewDidLoad() {
super.viewDidLoad()
pageControl.currentPage = index
facebookButton.hidden = (index == 3 ) ? false : true
pageControl.hidden = (index == 3) ? true: false
logoImageView.image = UIImage(named: logoFile)
contentLabel.text = content
backgroundImageView.image = UIImage(named: backgroundFile)
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if let destinationController = segue.destinationViewController as? PaymentSubViewController
where segue.identifier == "payment" {
// Do something with `destinationController`
}
}
#IBAction func test(sender: AnyObject) {
self.performSegueWithIdentifier("payment", sender: self)
}
#IBAction func fbTouched(sender: AnyObject) {
FBSDKLoginManager().logInWithReadPermissions(self.facebookReadPermissions, handler: { (result:FBSDKLoginManagerLoginResult!, error:NSError!) -> Void in
if error != nil {
//According to Facebook:
//Errors will rarely occur in the typical login flow because the login dialog
//presented by Facebook via single sign on will guide the users to resolve any errors.
// Process error
FBSDKLoginManager().logOut()
} else if result.isCancelled {
// Handle cancellations
FBSDKLoginManager().logOut()
} else {
let fbToken = result.token.tokenString
Alamofire.request(Router.FacebookAuth(fbToken)).validate(statusCode: 200 ..< 300).responseJSON(completionHandler: { (request, response, JSON, error) in
if let json = JSON as? Dictionary<String, AnyObject> {
if let token = json["token"] as? String {
Router.OAuthToken = token
self.performSegueWithIdentifier("showHomeFeed", sender: self)
}
}
})
}
})
}
}
Because you are force unwrapping the destinationViewController using as!, if that value is nil or not a PaymentSubViewController, the app will crash.
The better way to implement this is with an optional binding (if let) and a conditional downcast (as?):
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if let destinationController = segue.destinationViewController as? PaymentSubViewController
where segue.identifier == "payment" {
// Do something with `destinationController`
}
}
Of course, that'll stop the crash but won't answer the question of why segue.destinationViewController is nil or of another type. Make sure that you segue is configured properly in interface builder and that the destination view controller actually has segue.destinationViewController for its Class value in the identity inspector tab.
I had a map object on the storyboard and I did not add an outlet for the object which was creating an error message.