Trying to call a navigation bar function in another class pragmatically - ios

Question

I created a navigation bar which I'm trying to call in another view controller. I set it up by calling the methods which I separated into left, center and right buttons. In my other controller I call the navbarcontroller and try and call the method for which i setup the navigation toolbar. Nothing happens, however there is no crash.
import UIKit
class NavBarController : UIViewController{
var screenSize: CGRect!
override func viewDidLoad() {
super.viewDidLoad()
setupNavigationBarItems()
setupToolBarItems()
self.navigationController?.isToolbarHidden = false
self.view!.backgroundColor = .white
}
and my method for the navigation bar is this
func setupNavigationBarItems() {
setupCenterNavButton()
setupLeftNavButton()
setupRightNavButton()
}
func showCalendarController() {
let navController = CalendarController()
self.present(navController, animated: true, completion: nil)
} //connect bottom bar buttons to controller
func showEventsController() {
let navController = EventsController()
self.present(navController, animated: true, completion: nil)
} //connect bottom bar buttons to controller
func setupNavigationBarItems() {
setupCenterNavButton()
setupLeftNavButton()
setupRightNavButton()
} // top bar button setup
private func setupCenterNavButton() {
let buttonFrame = UIView(frame: CGRect(x: 0, y: 0, width: 165,
height: 20))
mainFeedButton.frame = CGRect(x: 0,y: 0, width: 80,height: 20) as
CGRect
mainFeedButton.backgroundColor = UIColor.blue
peekFeedButton.frame = CGRect(x: 85,y: 0, width: 80,height: 20) as
CGRect
peekFeedButton.backgroundColor = UIColor.blue
buttonFrame.addSubview(mainFeedButton)
buttonFrame.addSubview(peekFeedButton)
navigationItem.titleView = buttonFrame
} //center bar buttons / action setup
private func setupLeftNavButton() {
navigationItem.leftBarButtonItem = UIBarButtonItem(customView:
favoriteButton)
}// left bar buttons / action setup
private func setupRightNavButton() {
navigationItem.rightBarButtonItem = UIBarButtonItem(customView:
moreButton)
} //right bar buttons / action setup
lazy var mainFeedButton: UIButton! = {
let button = UIButton(type: .custom) // button type
button.setTitle("Main",for: .normal) //button title
button.sizeToFit() // size button to fit the title
var frame = button.frame //create frame to manipulate the body
button.frame = CGRect(x: 0, y: 0, width: 100, height: 40)
button.addTarget(self, action:
#selector(self.showMainFeedController),
for: .touchUpInside)
return button
}() //mainFeed button connected to Feed Controller
lazy var peekFeedButton: UIButton! = {
let button = UIButton(type: .custom) //button type
button.setTitle("Spy",for: .normal) //button title
button.sizeToFit() // size button to fit the title
var frame = button.frame //create frame to manipulate the body
button.frame = CGRect(x: 20, y: 0, width: 100, height: 40)
button.addTarget(self, action:
#selector(self.showSpyFeedController),
for: .touchUpInside)
return button
}()//peekFeed button frame and action setup
lazy var favoriteButton: UIButton! = {
let button = UIButton(type: .system) //default button with blue
text
button.setImage(#imageLiteral(resourceName:
"star").withRenderingMode(.alwaysOriginal), for: .normal)
button.contentMode = .scaleAspectFit
button.frame = CGRect(x: 0, y: 0, width: 24, height: 24)
button.addTarget(self, action: #selector(favoriteButton_tapped),
for: .touchUpInside)
return button
}() //favorites button frame and action setup
lazy var moreButton: UIButton! = {
let button = UIButton(type: .system) //default button with blue
text
button.setImage(#imageLiteral(resourceName:
"more").withRenderingMode(.alwaysOriginal), for: .normal)
button.contentMode = .scaleAspectFit
button.frame = CGRect(x: 0, y: 0, width: 24, height: 24)
button.addTarget(self, action: #selector(moreButton_tapped),
for: .touchUpInside)
return button
}() //more button frame and action setup
func showMainFeedController() {
let navController = MainFeedController()
self.present(navController, animated: true, completion: nil)
} //mainFeed button connected to Feed Controller
func showSpyFeedController() {
let navController = SpyFeedController()
self.present(navController, animated: true, completion: nil)
}//peekFeed button connected to SpyFeedController
func favoriteButton_tapped(sender: UIButton) {
print("You touched this!")
}
func moreButton_tapped(sender: UIButton) {
print("You touched this!")
}
}
I then try and call the function by setupNavigationBarItems() like this
import UIKit
class EventsController: UIViewController{
override func viewDidLoad() {
super.viewDidLoad()
let navbar = NavBarController()
navbar.setupNavigationBarItems()
self.navigationController?.isToolbarHidden = false
self.view.backgroundColor = .white
}
}
I'm not sure if this a valid way. I'm still kinda new to all of this.

Answer 1

It's not clear what you expect to happen, but here's what does happen:
let navbar = NavBarController()
A completely new NavBarController object is created.
navbar.setupNavigationBarItems()
That NavBarController object's setupNavigationBarItems is called.
self.navigationController?.isToolbarHidden = false
self.view.backgroundColor = .white
Your code comes to an end. navbar was a local variable, so the NavBarController object vanishes in a puff of smoke. The end. This object was created and configured to no purpose.

Answer 2

I remember my first month in iOS way back 2015 :D, didn't have any knowledge in OOP, I didn't know too how to pass a data to another screen or class.
Anyways, you DO NOT create a new instance of your NavBarController class in your EventsController. If you want to talk to your NavBarController from your EventsController, then you will need a reference that is currently alive. You can also use delegate (search for that later).
So before you show or present your EventsController from your NavBarController, pass your current NavBarController instance to the next screen which is EventsController. BUT FIRST, you need to declare a variable in your EventsController, correct? :)
Declare a variable with a type of NavBarController inside your EventsController class, like so:
var navBarController: NavBarController!
Then in this piece of code of yours, pass your self (the NavBarController instance) to the EventsController class before showing or presenting, take note that you mistakenly gave a wrong name to your EventsController new instance, so I renamed it:
func showEventsController() {
let eventsController = EventsController()
eventsController.navBarController = self // THIS :)
self.present(eventsController, animated: true, completion: nil)
}
Lastly, instead of this:
let navbar = NavBarController()
navbar.setupNavigationBarItems()
Make use of your declared variable, like so:
self.navBarController.navbar.setupNavigationBarItems()
Hope this helps! :)