Swift: call a ViewController func from another viewcontroller - ios

Question

I have a function "addDoneButton" in FirstViewController.swift, I don't want to copy and paste into the SecondViewController.swift, so I want to call it in the SecondViewController.
func addDoneButton() {
let keyboardToolbar = UIToolbar()
keyboardToolbar.sizeToFit()
let flexBarButton = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace,
target: nil, action: nil)
let doneBarButton = UIBarButtonItem(barButtonSystemItem: .Done,
target: view, action: #selector(UIView.endEditing(_:)))
keyboardToolbar.items = [flexBarButton, doneBarButton]
for textField in self.collectionOfTextField! as [UITextField] {
textField.keyboardType = .DecimalPad
textField.inputAccessoryView = keyboardToolbar
}
}
How to realise it? Thanks in advance from a new swifter.

Answer 1

How about creating an extension of UIViewController and passing the collectionTextFields as an argument?
extension UIViewController {
func addDoneButton(collectionTextFields: [UITextField]) {
let keyboardToolbar = UIToolbar()
keyboardToolbar.sizeToFit()
let flexBarButton = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace,
target: nil, action: nil)
let doneBarButton = UIBarButtonItem(barButtonSystemItem: .Done,
target: view, action: #selector(UIView.endEditing(_:)))
keyboardToolbar.items = [flexBarButton, doneBarButton]
for textField in collectionTextFields {
textField.keyboardType = .DecimalPad
textField.inputAccessoryView = keyboardToolbar
}
}
}

Answer 2

You can make a protocol, then put this method in a protocol extension where self: UIViewController. Then any UIViewController subclass that you want to enable this function, just add the CanAddDoneButton to the protocols it conforms to.. with the caveat that it already has that collectionTextFields variable. Although I think you can even put that variable into the protocol extension, unless it's an IBOutlet.
protocol CanAddDoneButton {
var collectionTextFields: [UITextField]
func addDoneButton()
}
extension CanAddDoneButton where Self: UIViewController {
func addDoneButton() { .... }
}

Answer 3

I think EridB answer is a good way.
Alternatively what about a Swift 2 protocol extension? Its similar to his answer with the only difference being that not all ViewControllers get access to the method unless you conform to the protocol.
protocol Button { }
extension Button where Self: UIViewController {
func addDoneButton(forCollectionTextFields collectionTextFields: [UITextField]) {
let keyboardToolbar = UIToolbar()
keyboardToolbar.sizeToFit()
let flexBarButton = UIBarButtonItem(barButtonSystemItem: .FlexibleSpace,
target: nil, action: nil)
let doneBarButton = UIBarButtonItem(barButtonSystemItem: .Done,
target: view, action: #selector(UIView.endEditing(_:)))
keyboardToolbar.items = [flexBarButton, doneBarButton]
for textField in collectionTextFields {
textField.keyboardType = .DecimalPad
textField.inputAccessoryView = keyboardToolbar
}
}
}
Than in your viewControllers that need to call this method you conform to the protocol and just call it.
class SomeViewController: UIViewController, Button {
override func viewDidLoad() {
super.viewDidLoad()
addDoneButton(forCollectionTextFields: self.collectionOfTextField)
}
}
Hope this helps

Answer 4

Just try this in your SecondViewController.swift:
let firstViewController = FirstViewController()
And any times you need the function just call:
firstViewController.addDoneButton()