I have tried 2 methods to pass the data from ViewController to ContainerView, with and without segue
Here is without segue method
ViewController
class DetailPostBookReviewVC: UIViewController {
var postid: String!
#IBAction func Menubutton(_ sender: Any) {
print(postid!)
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "MenuBookReviewVC") as! MenuBookReviewVC
vc.favpostid = postid
}
ContainerView
class MenuBookReviewVC: UIViewController {
var favpostid = String()
#IBAction func Deletepost(_ sender: Any) {
print(favpostid)
}
}
result: favposid has Nill Value
UPDATE this is with segue method
class DetailPostBookReviewVC: UIViewController {
var postid: String!
#IBAction func Menubutton(_ sender: Any) {
print(postid!)
func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?){
if (segue.identifier == "toMenuBookReviewVC") { //"toMenuBookReviewVC" is identifier
let vc = segue.destination as! MenuBookReviewVC
vc.favpostid = postid!
}
}
Pass your data like. User prepare(for:sender:)
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if
segue.identifier == "MyIdentifierInStorybiard", // Set that
let controller = segue.destination as? MenuBookReviewVC {
controller.favpostid = postid
}
}
I think you postid is not String type so print the null value
In this way, you can't pass data for the container view. if in this way without presenting controller and push controller you can use the global variable then direct pass data and use any controller you want to use.
Example
import UIKit
class ViewController: UIViewController {
var postid: String!
override func viewDidLoad() {
super.viewDidLoad()
postid = "23" // You change your post ID
}
#IBAction func Menubutton(_ sender: Any) {
favpostid = postid
}
}
var favpostid : String!
class MenuBookReviewVC: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
print(favpostid)
}
}
For Passing Data To Container View you can use this
UserDefaults.standard.set(value, forKey: "SomeKey")
after your data is used you can clear that default value.
UserDefaults.standard.set("", forKey: "SomeKey")
Related
I want to send my UserModel with all user informations from a ViewController (ShowUserViewController) to another ViewController (ChatViewController) with a delegate but its not working.
In my ShowUserViewControllers user are all informations I want to send to the ChatViewController.
var user: UserModel?
In my ChatViewController I have the following declaration where I want to send my datas:
var currentUser: UserModel?
Here my protocol:
protocol UserInfoToChatID {
func observeUserID(user: UserModel)
}
Here I prepare the segue and set delegate by tapping the button:
} else if segue.identifier == "UserInfoToChatVC" {
let chatVC = segue.destination as! ChatViewController
chatVC.currentUser = self.user
}
}
var delegate: UserInfoToChatID?
#IBAction func chatButtonTapped(_ sender: UIBarButtonItem) {
delegate?.observeUserID(user: user!)
}
At last I call the delegate in my ChatViewController:
extension ChatViewController: UserInfoToChatID {
func observeUserID(user: UserModel) {
self.currentUser = user
performSegue(withIdentifier: "UserInfoToChatVC", sender: self)
}
}
If you need to pass data from one ViewController to another, you don't have to use delegates for this. You can just pass this data as sender parameter of performSegue method:
performSegue(withIdentifier: "UserInfoToChatVC", sender: user!)
then in prepare for segue just downcast sender as UserModel and assign destination's currentUser variable
...
} else if segue.identifier == "UserInfoToChatVC" {
let chatVC = segue.destination as! ChatViewController
chatVC.currentUser = sender as! UserModel
}
}
But in your case you actually don't have to pass user as sender. You can just assign destination's currentUser variable as ShowUserViewController's global variable user
...
} else if segue.identifier == "UserInfoToChatVC" {
let chatVC = segue.destination as! ChatViewController
chatVC.currentUser = user!
}
}
2 things:
first, if you just want to pass data from one viewController to other viewController you don't need to use delegate pattern, just pass the object to the next viewController on prepare form segue.
second, if you want to implement the delegate pattern you should have one viewController than call to the delegate and the other implement the functions.
example:
protocol ExampleDelegate: class {
func delegateFunction()
}
class A {
//have delegate var
weak var delegate: ExampleDelegate?
// someWhere in the code when needed call to the delegate function...
delegate?.delegateFunction()
}
Class B: ExampleDelegate {
func delegateFunction() {
// do some code....
}
//when you move to the next viewControoler(to A in that case)
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "AClass" {
if let vc = segue.destination as? A {
vc.delegate = self
}
}
}
To pass the UserModel object forward, from ShowUserViewController to ChatViewController, you should use something called Dependency Injection:
So you'll do something like this inside ShowUserViewController:
#IBAction func chatButtonTapped(_ sender: UIBarButtonItem) {
performSegue(withIdentifier: "UserInfoToChatVC", sender: nil)
}
Note: The sender parameter should be the object that initiated the segue. It could be self, i.e. the ShowUserViewController object, but I'd advise against passing the UserModel object, because that object did not initiate the segue, and has nothing to do with navigation at all. It should be injected inside the Destination Controller later on.
In the same file, override the prepare(for:) method:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "UserInfoToChatVC" {
let chatVC = segue.destination as! ChatViewController
chatVC.currentUser = self.user
}
}
I believe you've mostly done this part right, but you may need to communicate back from ChatViewController to ShowUserViewController.
In that case, you can and should use Delegation.
Create something like this inside ShowUserViewController:
protocol ChatViewControllerDelegate: class {
func didUpdateUser(_ model: UserModel)
}
class ChatViewController: UIViewControler {
var user: UserModel?
weak var delegate: ChatViewControllerDelegate?
/* more code */
func someEventHappened() {
delegate?.didUpdateUser(self.user!)
}
}
Finally, there is an additional line to be added to the prepare(for:) method:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "UserInfoToChatVC" {
let chatVC = segue.destination as! ChatViewController
chatVC.currentUser = self.user
// Add this line...
chatVC.delegate = self
}
}
And specify that the ShowUserViewController implements the ChatViewControllerDelegate protocol, then override the didUpdateUser(_:) method:
func didUpdateUser(_ model: UserModel) {
// Some code here
}
I'm having a problem passing array data back from one view controller ("VC2") to another ("VC1"). I do everything by the rules. I made a proper protocol in VC1.
But unfortunately I could not get the data back.
This is my code:
VC2
protocol RecivedData {
func dataRecived(nameArray: [String] , priceArray: [String])
}
var popUpdelegate : RecivedData?
#IBAction func nextBtnTapped(_ sender: UIButton) {
print("Hello")
let namedata = itemNameArr
let namePrice = itemPriceArr
self.popUpdelegate?.dataRecived(nameArray: namedata, priceArray: namePrice)
print(namedata)
print(namePrice)
self.view.removeFromSuperview()
}
VC1
class HomeVC: UIViewController , RecivedData {
func dataRecived(nameArray: [String], priceArray: [String]) {
itemNameArr += nameArray
itemPriceArr += priceArray
print(itemNameArr, itemPriceArr)
print ("This is HomeVC")
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "sendSegue"{
let secondVC: AddOnItemPopUpVC = segue.destination as! AddOnItemPopUpVC
secondVC.popUpdelegate = self
}
}
}
Replace your code with this
protocol RecivedData : class {
func dataRecived(nameArray: [String] , priceArray: [String])
}
And
weak var popUpdelegate : RecivedData?
Now it will start working.
Make sure there will be no typo in segue name.
I'm trying to get the value of a String var from an another class, but when i'm using it on the new class, the value is empty.
I've got the MainViewController.swift class with :
var movieIDSelected = String()
#IBAction func tapPosterButton(_ sender: UIButton) {
switch sender.tag
{
case 101: movieIDSelected = theaterMovieID[0]
print(movieIDSelected) //The value isn't empty
break
}
}
And the second MovieViewController.swift class with :
var HomeView = ViewPop()
override func viewDidLoad() {
super.viewDidLoad()
let movieID = HomeView.movieIDSelected
print(movieID) //The value is empty
}
With your current code try this in MainVC
if let home = UIApplication.shared.keyWindow?.rootViewController as? ViewPop {
print("home exists ",home.movieIDSelected)
}
//
but you should have only 1 segue to the destinationVC and link it to the VC not a segue for every button , then implement prepareForSegue and fire performSegue inside the button action to make the segue
//
#IBAction func tapPosterButton(_ sender: UIButton) {
switch sender.tag
{
case 101: movieIDSelected = theaterMovieID[0]
print(movieIDSelected) //The value isn't empty
self.performSegue(withIdentifier: "goToNext", sender:1)
break
}
}
//
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let des = segue.destination as! MovieViewController
des.sendedValue = self.movieIDSelected
des.buttonNumber = sender as! Int
}
//
class MovieViewController : UIViewController {
var sendedValue = ""
var buttonNumber = 0 // default value won't affect
}
I'm trying to perform a segue which it doesn't work.
What i'm trying to do is send the data which i have in a textfield in my View Controller(Main), after that i want to send it to a ViewController called OperationsController and after that send it to another Views (CreateController & ListController) so i can use that same data and send it to a php file and get data to populate a table view in ListController. And for CreateController to get the email (which is in short words the data) and perform a query based on the email and insert into the database.
Anyways i tried sending the data to Operations into a label and doesn't work.
This is my code
ViewController: .
import UIKit
class ViewController: UIViewController {
var datas:[Usuario]?
struct Usuario : Codable {
let correo: String?
let contrasena: String?
}
#IBOutlet weak var txtError: UILabel!
#IBOutlet weak var txtCorreo: UITextField!
#IBOutlet weak var txtContra: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func btnLogear(_ sender: Any) {
let urlString = "http://localhost:8080/swiftdb/logear.php"
guard let url = URL(string: urlString) else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil {
print(error!.localizedDescription)
}
guard let data = data else { return }
//Implement JSON decoding and parsing
do {
//Decode retrived data with JSONDecoder and assing type of Article object
let articlesData = try JSONDecoder().decode([Usuario].self, from: data)
//Get back to the main queue
DispatchQueue.main.async {
self.datas = articlesData
let aarti = self.datas
for item in aarti! {
let correos = item.correo
let contras = item.contrasena
if(item.correo == self.txtCorreo.text && item.contrasena == self.txtContra.text){
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "OP") as! OpcionesController
self.present(nextViewController, animated:true, completion:nil)
self.performSegue(withIdentifier: "segue", sender: self)
self.txtError.text = " "
} else {
self.txtError.text = "Datos Incorrectos"
}
}
}
} catch let jsonError {
print(jsonError)
}
}.resume()
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? OpcionesController{
destination.name = txtCorreo.text
}
}
}
OperationsController: .
import UIKit
class OpcionesController: UIViewController {
var name: String?
#IBOutlet weak var displayLbl: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
if let nametoDisplay = name {
displayLbl.text = name
}
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// 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.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
Before calling presentViewController add :
nextViewController.name = yourTextField.text
You could also delete the segue call. That is redundant.
Here is an example that I've used in the past :
#IBAction func doSegue(_ sender: UIButton) {
buttonTag = sender.tag
let storyboard = UIStoryboard (name: "Main", bundle: nil)
let resultVC = storyboard.instantiateViewController(withIdentifier: "ResultViewController")as! ResultViewController
// Communicate with new VC - These values are stored in the destination
// you can set any value stored in the destination VC here
resultVC.firstValue = buttonTag
resultVC.secondValue = randomOpponentValue()
self.navigationController?.pushViewController(resultVC, animated: true)
}
1.So get rid of this code, because if you are calling performSegue you don’t need that one.
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "OP") as! OpcionesController
self.present(nextViewController, animated:true, completion:nil)
2.Then in the prepareForSegue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == “YourSegueIdentifier" {
let destination: OpcionesController = segue.destination as! OpcionesController
destination.name = txtCorreo.text
}
}
3.Replace this code:
if let nametoDisplay = name {
displayLbl.text = name
}
with:
displayLbl.text = name
I'm trying to pass data using a prepare(for segue:) function but it's showing nil in the second VC. Am I doing anything wrong?
class ViewController: UIViewController {
var first : [String] = []
#IBOutlet weak var passField: UITextField!
#IBOutlet weak var userID: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func login(_ sender: Any) {
let user : String = self.userID.text!
let password : String = self.passField.text!
if user != "" && password != "" {
let postString = ["username":user, “password”: password]
var request = URLRequest(url:URL(string:"http://mydomainhere.com/api/login")!)
request.httpMethod = "POST"
request.httpBody = try! JSONSerialization.data(withJSONObject: postString, options:.prettyPrinted)
let task = URLSession.shared.dataTask(with: request) { (data: Data?, response: URLResponse?, error: Error?) in
if error != nil {
print("error=\(error)")
return
}
do {
if let json = try JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? [String: Any] {
let firstName = json["first_name"] as? String
let lastName = json["last_name"] as? String
self.first.append(firstName!) //putting into Array
self.performSegue(withIdentifier: "loginSegue", sender: self)
}
} catch {
print(error)
}
}
}
}
// data transfer to another controller
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "loginSegue" {
let secondController = segue.destination as? SecondVC
secondController?.name = first //passing to next VC //* here having the issue its not passing the data to next VC
print(first) // here first is printing perfectly
}
}
}
// second View Controller
class SecondVC: UIViewController {
var menu_vc : MenuViewController!
var name : [String]? // passing to this Array
override func viewDidLoad() {
super.viewDidLoad()
print(name) // here printing nil
}
}
As suggested by #Sweeper, it could very well be that your destination view controller is embedded in a UINavigationViewController, hence your segue.destination is in fact a UINavigationViewController, not a SecondVC.
You can try this code:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
var destinationViewController = segue.destination
if let navigationController = destinationViewController as? UINavigationController {
destinationViewController = navigationController.visibleViewController ?? destinationViewController
}
if let secondController = destinationViewController as? SecondVC {
secondController?.name = first
}
}
Of course the first four lines of code could be refactored in an appropriate function (even better if in an extension of UIViewController).
If that solves the problem, you can watch cs193p Stanford iOS course for further details.
In particular watch https://www.youtube.com/watch?v=HQrXM2zUPvY&index=6&list=PLPA-ayBrweUz32NSgNZdl0_QISw-f12Ai starting from the 30:20 mark.
Everything seems perfect with the below snippet
var first : [String] = []
#IBAction func btnTapped(_ sender: Any) {
let firstName = "iOS Geek"
self.first.append(firstName)
self.performSegue(withIdentifier: "MovetoSecVC", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "MovetoSecVC"{
let secVC = segue.destination as! SecondVC
secVC.name = first
print(first) // it'll print here ["iOS Geek"]
}
}
// Your Second View Controller
class SecondVC: UIViewController {
var menu_vc : MenuViewController!
var name : [String]? // passing to this Array
override func viewDidLoad() {
super.viewDidLoad()
print(name!) // it'll print here ["iOS Geek"]
}
}