Back to my first swift app, I'm doing the sign in/sign up part, and basically the design with the view controllers so far are:
Welcome screen (sign in/sign up buttons) - Sign in - Sign up - Main Program
I got to the part where in the sign up view controllers, if the user misses one of the required field blanks and they click the button "submit", they will be prompted and back to the current view controller (sign up) to fill the missing fields. Now I want to set that when all the fields are filled, what line of code can I use so when they click the button "submit" it will head back to the welcome screen, so they can sign in afterwards?
Similarly, I got all the the part to check if the user enters correct user name and password, so when they entered the wrong info, they will be prompted and hack to the current view controller (sign in), and how can I do so if they entered the correct user name - password, it will head to the main program view controller (the 4th one)
If what I said above is confusing, I'll post my current controllers and the related code in here. Anyone has any idea? Again, this is my first program so it'd mean very much if I can get some helps from you. Thank you for reading.
An example on how to do it:
import UIKit
class WelcomeVC: UIViewController {
//make it IBAction or call it from IBAction
func singInButtonPressed(){
performSegueWithIdentifier("sign in", sender: self)
}
//make it IBAction or call it from IBAction
func singUPButtonPressed(){
performSegueWithIdentifier("sign up", sender: self)
}
}
class SignUPVC: UIViewController {
#IBOutlet var userNameField:UITextField!
#IBOutlet var passwordField:UITextField!
//make it IBAction or call it from IBAction
func submit(){
if checkValidity() {
presentingViewController?.dismissViewControllerAnimated(true, completion: nil)
}
}
func checkValidity() ->Bool{
if !userNameField.text!.isEmpty{
if !passwordField.text!.isEmpty {
return true
} else {
//do something to inform passwordfield is missing
}
} else{
//username field is missing
}
return false
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "sign in" {
if let sINvc = segue.destinationViewController.contentViewController as? SignInVC{
sINvc.username = userNameField.text
sINvc.password = passwordField.text
//and pass more of the other info you gathered in this vc
}
}
}
}
class SignInVC: UIViewController {
#IBOutlet var userNameField:UITextField!{
didSet {
if username != nil { userNameField.text = username }
}
}
#IBOutlet var passwordField:UITextField! {
didSet {
if password != nil { passwordField.text = password }
}
}
var password:String?
var username:String?
//make it IBAction or call it from IBAction
func signInPressed(){
if !userNameField.text!.isEmpty && !passwordField.text!.isEmpty {
performSegueWithIdentifier("Main page", sender: self)
}
}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "Main page"{
//your preparation
}
}
}
//this extension is helpful to avoid typing this everytime there is nav vc in your way of segueing
extension UIViewController{
var contentViewController: UIViewController {
if self is UINavigationController{
if let cvc = (self as! UINavigationController).visibleViewController { return cvc }
}
return self
}
}
simple way to transfer one view to another in swift is this given below:-
let storyboard = UIStoryboard(name: "Main", bundle: nil)
//in "Main" your storyboard name
let secondViewController = storyboard.instantiateViewControllerWithIdentifier("LoginPage") as! UIViewController
//in place of Login Page your storyboard identifier name
navigationController?.pushViewController(secondViewController, animated: true)
let storyBoard = UIStoryboard(name: "Main", bundle: nil)
let mainTabBar = storyBoard.instantiateViewController(withIdentifier: "MainTabBar") as! UITabBarController
self.navigationController?.pushViewController(mainTabBar, animated: true)
works for me. thanks! update for the swift 3.1 and Xcode 8.3.2
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
}
Consider two view controller Controller1 and Controller2, I have created a form of many UITextField in controller 1, in that when a user clicks a particular UITextField it moves to Controller2 and he selects the data there.
After selecting the data in Controller2 it automatically moves to Controller1, while returning from controller2 to controller1 other UITextfield data got cleared and only the selected data from controller2 is found. I need all the data to be found in the UITextfield after selecting.
Here is the code for returning from Controller2 to Controller1
if(Constants.SelectedComplexName != nil)
{
let storyBoard: UIStoryboard = UIStoryboard(name: "NewUserLogin", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "NewUser") as! NewUserRegistrationViewController
self.present(newViewController, animated: true, completion: nil)
}
To pass messages you need to implement Delegate.
protocol SecondViewControllerDelegate: NSObjectProtocol {
func didUpdateData(controller: SecondViewController, data: YourDataModel)
}
//This is your Data Model and suppose it contain 'name', 'email', 'phoneNumber'
class YourDataModel: NSObject {
var name: String? //
var phoneNumber: String?
var email: String?
}
class FirstViewController: UIViewController, SecondViewControllerDelegate {
var data: YourDataModel?
var nameTextField: UITextField?
var phoneNumberTextField: UITextField?
var emailTextField: UITextField?
override func viewDidLoad() {
super.viewDidLoad()
callWebApi()
}
func callWebApi() {
//After Success Fully Getting Data From Api
//Set this data to your global object and then call setDataToTextField()
//self.data = apiResponseData
self.setDataToTextField()
}
func setDataToTextField() {
self.nameTextField?.text = data?.name
self.phoneNumberTextField?.text = data?.phoneNumber
self.emailTextField?.text = data?.email
}
func openNextScreen() {
let vc2 = SecondViewController()//Or initialize it from storyboard.instantiate method
vc2.delegate = self//tell second vc to call didUpdateData of this class.
self.navigationController?.pushViewController(vc2, animated: true)
}
//This didUpdateData method will call automatically from second view controller when the data is change
func didUpdateData(controller: SecondViewController, data: YourDataModel) {
}
}
class SecondViewController: UIViewController {
var delegate: SecondViewControllerDelegate?
func setThisData(d: YourDataModel) {
self.navigationController?.popViewController(animated: true)
//Right After Going Back tell your previous screen that data is updated.
//To do this you need to call didUpdate method from the delegate object.
if let del = self.delegate {
del.didUpdateData(controller: self, data: d)
}
}
}
push your view controller instead of a present like this
if(Constants.SelectedComplexName != nil)
{
let storyBoard: UIStoryboard = UIStoryboard(name: "NewUserLogin", bundle: nil)
let newViewController = storyBoard.instantiateViewController(withIdentifier: "NewUser") as! NewUserRegistrationViewController
self.navigationController?.pushViewController(newViewController, animated: true)
}
and then pop after selecting your data from vc2 like this
self.navigationController?.popViewController(animated: true)
and if you are not using navigation controller then you can simply call Dismiss method
self.dismiss(animated: true) {
print("updaae your data")
}
There are a few ways to do it, but it usually depends on how you move from VC#1 to VC#2 and back.
(1) The code you posted implies you have a Storyboard with both view controllers. In this case create a segue from VC#1 to VC#2 and an "unwind" segue back. Both are fairly easy to do. The link provided in the comments does a good job of showing you, but, depending on (1) how much data you wish to pass back to VC#1 and (2) if you wish to execute a function on VC#2, you could also do this:
VC#1:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "ShowVC2" {
if let vc = segue.destination as? VC2ViewController {
vc.VC1 = self
}
}
}
VC#2:
weak var VC1:VC1ViewController!
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if isMovingFromParentViewController {
VC1.executeSomeFunction()
}
}
Basically you are passing the entire instance of VC1 and therefore have access to everything that isn't marked private.
(2) If you are presenting/dismissing VC#2 from VC#1, use the delegate style as described by one of the answers.
VC#1:
var VC2 = VC2ViewController()
extension VC1ViewController: VC2ControlllerDelegate {
func showVC2() {
VC2.delegate = self
VC2.someData = someData
present(VC2, animated: true, completion: nil)
}
function somethingChanged(sender: VC2ViewController) {
// you'll find your data in sender.someData, do what you need
}
}
VC#2:
protocol VC2Delegate {
func somethingChanged(sender: VC2ViewController) {
delegate.somethingChanged(sender: self)
}
}
class DefineViewController: UIViewController {
var delegate:DefineVCDelegate! = nil
var someData:Any!
func dismissMe() {
delegate.somethingChanged(sender: self)
dismiss(animated: true, completion: nil)
}
}
}
Basically, you are making VC#1 be a delegate to VC2. I prefer the declaration syntax in VC#2 for `delegate because if you forget to set VC#1 to be a delegate for VC#2, you test will force an error at runtime.
I have got a tabbed project in my Xcode.But my Entry Point is a separate view controller that is not connected to tabs.So when user clicks Login button i send value of input to one of view controllers in tabbed part of my project.I have a segue between separated VC and VC that I send data to.Here is my code In part where I send the data
protocol SendDel {
func userDidEnterData(data: String)
}
LogInViewController: UIViewController {
var delegate:SendDel!=nil
#IBAction func SendB(_ sender: Any) {
if(delegate != nil){
if(self.Usn != nil){
let data = self.Usn.text
self.delegate?.userDidEnterData(data: data!)
}
}
}
}
And here is code in part where I receive data
class FirstViewController: UIViewController,SendDel {
func userDidEnterData(data: String) {
UsernameLabel.text="\(data)"
dismiss(animated: false, completion: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if(segue.identifier == "First"){
let sendingVc=segue.destination as! LogInViewController
sendingVc.delegate = self
}
}
}
But unfortunately it is not working.
Actually you setting the delegate property from FirstViewController and then when you present the LogInViewController you have write the code var delegate:SendDel!=nil which makes delegate nil every time you tapped the button.
So try below code :
var delegate: SendDel?
Hope it works for you.
My table view cell displays an entity with two different button elements. I want to be able to launch a view controller that displays a selection of food items if I click on the first button and a different view controller that displays a selection of beverages when I click on the second button.
I am able to correctly pass the data to the new view controllers, but can't seem to dismiss the current view and load the new one. My code is like this:
In the table view cell
#IBAction func foodBtnPressed(_ sender: Any) {
print("foodBtn pressed")
print("customer is \(customer?.name)")
vc.loadChooserScreen(toChoose: "Food", forCustomer: customer!)
}
#IBAction func beverageBtnPressed(_ sender: UIButton) {
print("beverageBtn pressed")
print("customer is \(customer?.name)")
vc.loadChooserScreen(toChoose: "Beverage", forCustomer: customer!)
}
In the table view controller
func loadChooserScreen(toChoose: String, forCustomer: Customer) {
print("Choose \(toChoose)")
print("For \(forCustomer.name)")
if toChoose == "Food" {
let foodVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "foodMenu") as? FoodVC
foodVC?.loadCustomerToEdit(customer: forCustomer)
dismissVC(sender: Any.self)
}
else if toChoose == "Beverage" {
let beverageVC = UIStoryboard(name: "Main", bundle: nil).instantiateViewController(withIdentifier: "beverageMenu") as? BeverageVC
beverageVC?.loadCustomerToEdit(customer: forCustomer)
dismissVC(sender: Any.self)
}
else {
// do nothing
}
}
func dismissVC(sender: Any) {
print("Reached dismissVC function in selectionMenu")
dismiss(animated: true, completion: {
self.delegate!.dismissViewController()
})
}
In this view controller I also have the following protocol
protocol OrderVCProtocol {
func dismissViewController()
}
and have defined
var delegate: OrderVCProtocol!
In my root view controller
func dismissViewController() {
print("Reached dismissViewController function in rootView")
if let foodVC = self.storyboard?.instantiateViewController(withIdentifier: "foodMenu") {
self.present(foodVC, animated: true, completion: nil)
}
if let beverageVC = self.storyboard?.instantiateViewController(withIdentifier: "beverageMenu") {
self.present(beverageVC, animated: true, completion: nil)
}
}
And the delegate is set when the table view controller is called here
#IBAction func loadOrderView(_ sender: Any) {
let orderVC = self.storyboard?.instantiateViewController(withIdentifier: "orderView") as! OrderVC
orderVC.delegate = self
self.present(orderVC, animated: true, completion: nil)
}
Within my target view controllers I have the following function
func loadCustomerToEdit(customer: Customer) {
self.customerToEdit = customer
print("IN FoodVC THE CUSTOMER TO EDIT IS \(self.customerToEdit.name)")
}
and a corresponding one in the BeverageVC.
When I run the app, no errors are thrown and I get the following sample output in the console from my print statements:
foodBtn pressed
customer is Optional("John")
Choose Food
For Optional("John")
IN FoodVC THE CUSTOMER TO EDIT IS Optional("John")
Reached dismissVC function in selectionMenu
and a corresponding response if the beverage button is clicked.
Then nothing happens. So I know the data is correctly being passed to the new view controllers but I don't know how to dismiss the current screen and display the new one with the choices.
I hope my question is clear enough? I'm not sure what's wrong, but the console output clearly shows that the code runs fine until it tries to dismiss the current view.
EDITED TO ADD:
If I modify my dismissVC function in my tableview controller like this:
func dismissVC(sender: Any) {
print("Reached dismissVC function in selectionMenu")
delegate.dismissViewController()
}
the console view now throws
fatal error: unexpectedly found nil while unwrapping an Optional value
And if I modify it again to the following, It goes back to throwing no errors and getting stuck at the same place (i.e. printing the line "Stuck where delegate dismisses view"), showing that the delegate is still nil... but why is it nil when I'd set it in the root view and loaded it in this view?
func dismissVC(sender: Any) {
print("Reached dismissVC function in selectionMenu")
if delegate != nil {
delegate?.dismissViewController()
} else {
print("Stuck where delegate dismisses view")
}
I have solved my problem by implementing notifications via notification centre and delegates. Firstly, in my AppDelegate file I added this line at the bottom
let notifyCnt = NotificationCenter.default
Next, I modified my tableview cell functions to this
#IBAction func foodBtnPressed(_ sender: Any) {
notifyCnt.post(name: NSNotification.Name(rawValue: "toChoose"), object: nil, userInfo: ["toChoose": "Food", "forCustomer": customer])
}
#IBAction func beverageBtnPressed(_ sender: UIButton) {
notifyCnt.post(name: NSNotification.Name(rawValue: "toChoose"), object: nil, userInfo: ["toChoose": "Beverage", "forCustomer": customer])
}
Then, in the tableview controller I modified it to this:
protocol ChooserViewDelegate: class {
func loadChooserView(choice: String, forCustomer: Customer)
}
and defined
weak var delegate: ChooserViewDelegate?
and added this within my ViewDidLoad section
notifyCnt.addObserver(forName: Notification.Name(rawValue: "toChoose"), object: nil, queue: nil, using: loadChooserScreen)
and finally modified my chooser function like so:
func loadChooserScreen(notification: Notification) {
guard let userInfo = notification.userInfo,
let toChoose = userInfo["toChoose"] as? String,
let planToEdit = userInfo["customer"] as? Customer else {
print("No userInfo found in notification")
return
}
delegate?.loadChooserView(choice: toChoose, forCustomer: customer)
}
Then in my root view controller I have the following to replace what I had earlier:
/*Conform to ChooserViewDelegate Protocol */
func loadChooserView(choice: String, forCustomer: Customer) {
self.customer = forCustomer
dismiss(animated: false, completion: {
if choice == "Food" {
self.performSegue(withIdentifier: "food", sender: self.customer)
}
if choice == "Beverage" {
self.performSegue(withIdentifier: "beverage", sender: self.customer)
}
})
}
and I send over the data via prepareForSegue:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "food" {
if let foodVC = segue.destination as? FoodVC {
storyboard?.instantiateViewController(withIdentifier: "food")
foodVC.customerToEdit = self.customerToEdit
foodVC.delegate = self
}
}
if segue.identifier == "beverage" {
if let beverageVC = segue.destination as? BeverageVC {
storyboard?.instantiateViewController(withIdentifier: "beverage")
beverageVC.customerToEdit = self.customerToEdit
beverageVC.delegate = self
}
}
}
So now everything loads and views correctly :)
My Swift segue is not working at all and isn't throwing any errors. The breakpoint shows me that the app lands on this line but nothing happens:
self.performSegueWithIdentifier("SignupSegue", sender: self)
The code block is a login form with Facebook:
if let accessToken: FBSDKAccessToken = FBSDKAccessToken.currentAccessToken() {
PFFacebookUtils.logInInBackgroundWithAccessToken(result.token, block: {
(user: PFUser ? , error : NSError ? ) - > Void in
if user!.isNew {
self.performSegueWithIdentifier("SignupSegue", sender: self)
} else {
self.navigateToInGame(true)
}
})
}
Here's the segue function it should call, but doesn't even get to it:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{
if (segue.identifier == "SignupSegue") {
let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("SignUpViewController")
self.showViewController(vc, sender: self)
}
}
Any ideas?
Generally, any UI updating has to be in main thread. I think the block for PFFacebookUtils.logInInBackgroundWithAccessToken is still in the background state in above situation. Maybe trigger the showViewController in dispatch_async(dispatch_get_main_queue(), {}) and see if there is any difference.
dispatch_async(dispatch_get_main_queue(), {
let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewControllerWithIdentifier("SignUpViewController")
self.showViewController(vc, sender: self)
})
Ok. I just tried it out. Hope you did all the things regarding StoryBoard Reference.
Me too had the same issue with performSegueWithIdentifier.
Example:
Let take two storyboard main and signup.
1) In main.storyboard create a storyboard reference. Set the storyboardId in the Storyboard Reference as signup and the referencedId as the storyboardId of the scene(viewController) which is in signup.storyboard. Look at this link for a clear picture Storyboard to Storyboard
2) Set the segue identifier between viewController and Storyboard Reference in main.storyboard
3) Since I faced the same problem with performSegueWithIdentifier, I replaced it with shouldPerformSegueWithIdentifier.
override func shouldPerformSegueWithIdentifier(identifier: String, sender: AnyObject?) -> Bool {
if(identifier == "segue_identifier"){
// segue_identifier is the viewController and storyBoard Reference segue identifier.
print("hello")
}
return true;
}
Let me know if you find any issues. It did work for me.
Performing a segue leads to present a new view controller.You don't need to and can't create and show view controller in prepareForSegue.It will look like:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{
if (segue.identifier == "SignupSegue") {
let vc = segue.destinationViewController
}
}
Swift 3 solved:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "SignupSegue") {
DispatchQueue.main.async {
let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
let vc = storyboard.instantiateViewController(withIdentifier: "SignUpViewController")
self.show(vc, sender: self)
}
}
}
You can try this ...
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?)
{
if (segue.identifier == "SignupSegue") {
if let destination = segue.destination as? SignUpViewController {
...
}
}
}
The closest I can get to overcome same problem for myself:
Made trigger var segueLogin : Bool = false with initialised value in the Class.
When PFFacebookUtils gets needed values for segue, change trigger to true:
PFFacebookUtils.logInInBackground(withReadPermissions: permissions) {
(user: PFUser?, error: Error?) -> Void in
if let user = user {
if user.isNew {
print("User signed up and logged in through Facebook!")
self.segueLogin = true
} else {
print("User logged in through Facebook!")
self.segueLogin = true
}
} else {
print("Uh oh. The user cancelled the Facebook login.")
self.loginCancelledLabel.alpha = 1
}
}
Then added code to viewDidAppear class. Realised it starts everytime PFFacebookUtils complete. So it checks if returned value is true and performs segue after successful PFFacebookUtils session:
override func viewDidAppear(_ animated: Bool) {
if segueLogin == true {
self.performSegue(withIdentifier: "segueSingup", sender: self)
}
}