How do I call a function from a different view controller? - swift

Question

I have what is basically a notes app, and I am trying to call a function that is in one view controller from another. How do I do this, or is there a better way I should do it?
Here's where I am trying to call the function from
class NoteDetailViewController: UIViewController
{
#IBOutlet weak var funcButton: UIButton!
#IBAction func funcButTouched(sender: UIButton)
{
// where i want to call the function
}
}
And where the function is
class ListTableViewController: UITableViewController
{
// the function
func wordCount()
{
var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
for (index, element) in contentArr.enumerate()
{
let location = conciseArr.indexOf(element)
if (location != nil)
{
contentArr[index] = inflatedArr[location!]
afterStr = contentArr.joinWithSeparator(" ")
Project.sharedInstance.after = afterStr
}
}
}
}
I've tried just creating an instance of ListTableViewController and just calling the function that way but I get an error.

Answer 1

You could use delegation.
First, declare a delegate protocol. This should be in your NoteDetailViewController.swift file but outside of the class declaration:
protocol NoteDetailViewControllerDelegate: class {
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController)
}
Next, add a delegate property to your NoteDetailViewController:
weak var delegate: NoteDetailViewControllerDelegate?
Now, we use the #IBAction to tell the delegate, which will be the ListTableViewController:
#IBAction func funcButTouched(sender: UIButton)
{
delegate?.noteDetailViewControllerButtonTouched(self)
}
Finally, back in ListTableViewController (assuming this controller is the one directly before a NoteDetailViewController is shown), conform to the protocol and use prepareForSegue to set the delegate to itself:
class ListTableViewController: UITableViewController, NoteDetailViewControllerDelegate {
// ... more stuff ...
// Implement the delegate protocol
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController) {
// Do something! The button was pressed!
wordCount()
}
// Set ourselves as delegate when we are about to show the other view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let yourVC = segue.destinationViewController as? NoteDetailViewController {
yourVC.delegate = self
}
}
}
You should finish with something like this:
NoteDetailViewController.swift:
class NoteDetailViewController: UIViewController
{
#IBOutlet weak var funcButton: UIButton!
weak var delegate: NoteDetailViewControllerDelegate?
#IBAction func funcButTouched(sender: UIButton)
{
delegate?.noteDetailViewControllerButtonTouched(self)
}
}
protocol NoteDetailViewControllerDelegate: class {
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController)
}
ListTableViewController.swift:
class ListTableViewController: UITableViewController, NoteDetailViewControllerDelegate
{
// the function
func wordCount()
{
var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
for (index, element) in contentArr.enumerate()
{
let location = conciseArr.indexOf(element)
if (location != nil)
{
contentArr[index] = inflatedArr[location!]
afterStr = contentArr.joinWithSeparator(" ")
Project.sharedInstance.after = afterStr
}
}
}
// Implement the delegate protocol
func noteDetailViewControllerButtonTouched(controller: NoteDetailViewController) {
// Do something! The button was pressed!
wordCount()
}
// Set ourselves as delegate when we are about to show the other view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let yourVC = segue.destinationViewController as? NoteDetailViewController {
yourVC.delegate = self
}
}
}

Answer 2

Just follow bellow code its very simple :-
NoteDetailViewController.swift:
class NoteDetailViewController: UIViewController
{
#IBOutlet weak var funcButton: UIButton!
var parentListTableView : ListTableViewController!
#IBAction func funcButTouched(sender: UIButton)
{
parentListTableView.wordCount()
}
}
ListTableViewController.swift:
class ListTableViewController: UITableViewController
{
// the function
func wordCount()
{
var contentArr = Project.sharedInstance.content.componentsSeparatedByString(" ")
for (index, element) in contentArr.enumerate()
{
let location = conciseArr.indexOf(element)
if (location != nil)
{
contentArr[index] = inflatedArr[location!]
afterStr = contentArr.joinWithSeparator(" ")
Project.sharedInstance.after = afterStr
}
}
}
// Set ourselves as delegate when we are about to show the other view controller
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if let yourVC = segue.destinationViewController as? NoteDetailViewController {
yourVC.parentListTableView = self
}
}
}