I am totally new to the Mac apps development. I am facing an issue since last two days but could not succeed.
My problem is the same as question Swiching between 2 diferent NSViewControllers with data.
Could you please help me to understand the process and syntax of how to move from one NSViewController to another.
I have a View controller for login where I have two fields i.e. UserId and password.
On the click of the login button a web API is called to authenticate the user and upon receiving "SUCCESS" as the response, control should be transferred from LoginViewController to ProfileViewController.
I have tried to resole this issue as per the answer of the question (link given) but I am getting an error that. "fromviewcontroller.view.superview cannot be nil."
Create a segue from LoginViewController to ProfileViewController and give an identifier to it like "showProfile".
#IBAction func loginButton(_ sender: Any) {
// Code for validating User.
if response == "SUCCESS" {
performSegue(withIdentifier: "showProfile", sender: sender)
}
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
super.prepare(for: segue, sender: sender)
if segue.identifier == "showProfile" {
let profileController = segue.destinationController as! ProfileViewController
profileController.data = responseData
}
}
Not using storyboards?
#IBAction func loginButton(_ sender: Any) {
// Code for validating User.
if response == "SUCCESS" {
let profileController = ProfileViewController(nibName: "ProfileViewController", bundle: Bundle.main)
profileController.data = responseData
self.view.window!.contentViewController = profileController
}
}
You have to create a Segue in your Storyboard (Ctrl + Left click the yellow circle button above your LoginViewController and drag it to your ProfileViewController) and then name it something like "showProfile".
When you received your "SUCCESS" you want to call:
//here you enter the name of the segue you want to call
//& in sender the data you want to pass to the new VC.
performSegue(withIdentifier: "showProfile", sender: nil)
this will call
prepare(for segue: UIStoryboardSegue, sender: Any?)
in your current ViewController, so if you want to pass data to your new ViewController, you need to override it.
Example for passing data between ViewControllers :
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
//asking which segue is called
if segue.identifier == "showProfile" {
//when you called "showProfile", you can be sure that your
//destination is a ProfileViewController
let vc = segue.destination as! ProfileViewController
//passing the data to your new VC
vc.data = sender
}
}
Related
Struggling to get my viewControllers to send value from the main viewController to a second. I want it to happen on a button click, I'm going to get the value from the button and pass it to the new form. But it just isn't working.
Code for main ViewController
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func butClick(_ sender: UIButton) {
NSLog("Button Pressed : %#",[sender .currentTitle])
//var tt = [sender .currentTitle]
// Create the view controller
let vc = TimesTablesViewController(nibName: "TimesTablesViewController", bundle: nil)
vc.passedValue = "xx"
self.performSegue(withIdentifier: "pushSegue", sender: nil)
}
}
Code for second viewController called TimesTablesViewController:
class TimesTablesViewController: UIViewController {
#IBOutlet weak var titleLabel: UILabel!
var passedValue:String = ""
override func viewDidLoad() {
super.viewDidLoad()
titleLabel?.text = "\(passedValue) Times Table"
}
}
I've followed tutorials but can't seem to solve the problem! Thanks for any help!
Replace
self.performSegue(withIdentifier: "pushSegue", sender: nil)
with
self.present(vc,animated:true,completion:nil)
or ( if the current vc is inside a naigation )
self.navigationController?.pushViewController(vc,animated:true)
Using
self.performSegue(withIdentifier: "pushSegue", sender: nil)
is fit with storyboards not xibs and if this your case then you need to use the above line only inside the button action with implementing this method inside the source vc
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "pushSegue" {
if let nextViewController = segue.destination as? TimesTablesViewController{
nextViewController.passedValue = "xx"
}
}
}
I’m assuming that the new view controller is appearing, but you’re simply not seeing the data. If so, you’re evidently using storyboards. The TimesTablesViewController(nibName:bundle:) only works if you’re using XIB/NIBs and manually presenting new view controller.
If you’re really using storyboards, simplify your butClick method:
#IBAction func butClick(_ sender: UIButton) {
NSLog("Button Pressed")
performSegue(withIdentifier: "pushSegue", sender: self)
}
But implement prepare(for:sender:):
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let destination = segue.destination as? TimesTablesViewController {
destination.passedValue = "xx"
}
}
Assuming the above fixes your problem, I might suggest a further simplification. Notably, if your butClick(_:) method is really only calling performSegue, you can segue to this next scene without any #IBAction method at all:
remove butClick(_:) entirely;
remove the connection between the button and the butClick method in IB, on the “Connections Inspector” tab in the right panel; and
control-drag from the button previously hooked up to butClick(_:) to the scene for TimesTablesViewController.
That will simplify your code further.
I want my user to go to the TableViewController once they enter their "id" and "password" but when we use prepare and performsegue methods we just send one variable.
#IBAction func logIn(_ sender: Any) {
performSegue(withIdentifier: "emailSegue", sender: emailTextField.text)
performSegue(withIdentifier: "passwordSegue", sender: passwordTextField.text)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let guest = segue.destination as! ExpenseTableViewController
guest.incoming.append(sender as! String)
}
As you can see here I want to perform two different segues and I have also created two segues on the storyboard from ViewController to tableview controller named as "emailSegue" and "passwordSegue", but in the prepare function I can only prepare for the one of them which is the "emailSegue" when I run the code, it does compile and I can append email to the array but not my password.
So I wonder how I can get them both to be sent? Is there a way to prepare for 2 different segues? Could not find an example of it on anywhere else.
Thanks in advance.
You can only perform one segue, but you can send multiple parameters.
Just pass an array rather than a single string:
#IBAction func logIn(_ sender: Any) {
performSegue(withIdentifier: "emailSegue",
sender: [emailTextField.text!, passwordTextField.text!])
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "emailSegue" {
let guest = segue.destination as! ExpenseTableViewController
guest.incoming.append(contentsOf: sender as! [String])
}
}
PS: Rather than forced unwrapping the text properties you should validate them:
#IBAction func logIn(_ sender: Any) {
guard let email = emailTextField.text, !email.isEmpty,
let password = passwordTextField.text, !password.isEmpty else {
// show an alert
return
}
performSegue(withIdentifier: "emailSegue", sender: [email, password])
}
You can only perform one segue at a time, so call performSegue only once when you want the transition to happen and set the two variables in prepareForSegue for the destination view controller. It's best to check what type of segue should be prepared by checking segue.identifier property.
I'm working on a macOS project where I have a split view containing 2 other ViewControllers and I can't figure out how to access the ViewControllers from my primary window's ViewController.
this is the setup:
Basically what I'm trying to do is use the Button in my ViewController on the top-left to access the Label in my SectionController on the right, which is embedded in my split view.
Since I can't create an IBAction or IBOutlet for a control in a different ViewController, I can't figure out how to get these to be connected. My current workaround has been to have a property on my AppDelegate and then access the main shared application delegate, but that feels hacky and won't scale. I'm completely lost as to how to proceed. I'm ok with using a function to pass data or whatever to the other ViewController(s).
I'm using Swift 4 with Xcode 9 (beta).
Any ideas?
Of course you can't create IBAction or IBOutlet for a control in a different ViewController!!
But simply each view controller in the hierarchy has a reference for its child view controllers.
Method 1:
#IBAction func buttonTapped(_ sender: Any) {
let splitViewController = self.childViewControllers[0] as! YourSplitViewController
let targetViewController = splitViewController.childViewControllers[0] as! YourTargetViewController
targetViewController.label.text = "Whatever!"
}
Method 2:
It may be better if you took a reference for each child controller in your "prepare for segue" method
ContainerViewController:
var mySplitViewController: YourSplitViewController?
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "splitViewSegue" {
self.mySplitViewController = segue.destination as! YourSplitViewController
}
}
YourSplitViewController:
var aViewController: YourFirstViewController?
var bViewController: YourSecondViewController?
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "aViewSegue" {
self.aViewController = segue.destination as! YourFirstViewController
} else if segue.identifier == "bViewSegue" {
self.bViewController = segue.destination as! YourSecondViewController
}
}
So you can access it like that in your container view controller:
#IBAction func buttonTapped(_ sender: Any) {
self.mySplitViewController.firstViewController.label.text = "Whatever!"
}
I have a view controller with a lot (36) of buttons, and I want each of these buttons to segue to a particular view controller based on a variable that was set earlier in the program. In other words, any button could potentially go to 15 different view controllers based on a variable that was sent to the viewcontroller containing the buttons...
I think I can make this work if I click and drag each button to every viewcontroller... but it seems silly and messy.
I tried doing something like this:
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if variable == "Whatever" {
let send = segue.destination as! AViewController
send.variablesent = (sender as! UIButton).title(for: .normal)!}
}
But this only works if I click and drag the button in the storyboard to the "AViewController".
Any help is appreciated, thanks!!
For that you can make segue from SourceViewController to DestinationViewController instead of from Button to Controller, After that when you call perfromSegue in your button action then pass button reference as sender in perfromSegue call.
#IBAction func buttonAction(_ sender: UIButton) {
self.performSegue(withIdentifier: "segueIdentifier", sender: sender)
}
Now in prepareForSegue cast sender to UIButton and set title according to it.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if variable == "Whatever" {
let send = segue.destination as! AViewController
if let button = sender as? UIButton {
send.variablesent = button.titleLabel?.text ?? "Default value"
}
}
}
I have a scene which I open with this segue.
//pass all retrived info from signup field over to the login scene to facilitate user experience
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if (segue.identifier == "showLoginController") {
let svc = segue.destinationViewController as! LoginController;
print("pass data over to next viewcontroller")
}
}
This segue goes back to the Login screen where I want to set some values. However when the Login screen has not been loaded by segue "showLoginController", some fields should be empty.
How can I identify if LoginScene has been opened by a certain segue and set values accordingly?
In your LoginController view controller add this:
var fromSegue = false
And in prepareForSegue:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject!) {
if (segue.identifier == "showLoginController") {
let svc = segue.destinationViewController as! LoginController;
svc.fromSegue = true
print("pass data over to next viewcontroller")
}
}
And then in your LoginController you can check fromSegue.
You can know the segue from the previous scene, in the sender scene, implement prepareForSegue() method to detect the sender