Dismissing to rootViewController without calling each viewDidAppear - ios

Question

My View Contollers are like MainView -> NavigationController A -> ViewController A -> ViewController B -> ViewController C, I want to dismiss ViewControllers (A,B and C) and present MainView again... I used this line
self.view.window?.rootViewController?.dismiss(animated: false, completion: nil)
and it works just fine.. the problem is while dismissing viewControllers (A,B and C) it calls every viewDidAppear and this runs code that I don't want to be run.. what's the best practice to dismiss and go back to MainView without calling each viewController

Answer 1

You must have some other code that is causing the issue.
Here is a complete example...
PresDisViewController is the starting view controller
its button creates a nav controller with ViewControllerA as its root
ViewControllerA has a button that pushes ViewControllerB
ViewControllerB has a button that pushes ViewControllerC
ViewControllerC has a button that executes your self.view.window?.rootViewController?.dismiss(animated: false, completion: nil)
Each VC implements viewDidAppear() and prints itself to the debug console.
Output when I run it:
viewDidAppear scratchy.PresDisViewController
viewDidAppear scratchy.ViewControllerA
viewDidAppear scratchy.ViewControllerB
viewDidAppear scratchy.ViewControllerC
viewDidAppear scratchy.PresDisViewController
As you see, viewDidAppear is NOT called in the VCs when the nav controller is dismissed.
import UIKit
class ViewControllerA: UIViewController {
let btn: UIButton = {
let v = UIButton()
v.translatesAutoresizingMaskIntoConstraints = false
v.setTitle("Do Push", for: .normal)
v.backgroundColor = .red
return v
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(btn)
NSLayoutConstraint.activate([
btn.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: -40.0),
btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
])
btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)
}
#objc func didTap(_ sender: Any?) -> Void {
let vc = ViewControllerB()
self.navigationController?.pushViewController(vc, animated: true)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print("viewDidAppear", NSStringFromClass(self.classForCoder))
}
}
class ViewControllerB: UIViewController {
let btn: UIButton = {
let v = UIButton()
v.translatesAutoresizingMaskIntoConstraints = false
v.setTitle("Do Push", for: .normal)
v.backgroundColor = .systemYellow
return v
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(btn)
NSLayoutConstraint.activate([
btn.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 0.0),
btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
])
btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)
}
#objc func didTap(_ sender: Any?) -> Void {
let vc = ViewControllerC()
self.navigationController?.pushViewController(vc, animated: true)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print("viewDidAppear", NSStringFromClass(self.classForCoder))
}
}
class ViewControllerC: UIViewController {
let btn: UIButton = {
let v = UIButton()
v.translatesAutoresizingMaskIntoConstraints = false
v.setTitle("Do Dismiss", for: .normal)
v.backgroundColor = .blue
return v
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(btn)
NSLayoutConstraint.activate([
btn.centerYAnchor.constraint(equalTo: view.centerYAnchor, constant: 40.0),
btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
])
btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)
}
#objc func didTap(_ sender: Any?) -> Void {
self.view.window?.rootViewController?.dismiss(animated: false, completion: nil)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print("viewDidAppear", NSStringFromClass(self.classForCoder))
}
}
class PresDisViewController: UIViewController {
let btn: UIButton = {
let v = UIButton()
v.translatesAutoresizingMaskIntoConstraints = false
v.setTitle("Do Present", for: .normal)
v.backgroundColor = .orange
return v
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(btn)
NSLayoutConstraint.activate([
btn.topAnchor.constraint(equalTo: view.topAnchor, constant: 60.0),
btn.centerXAnchor.constraint(equalTo: view.centerXAnchor, constant: 0.0),
])
btn.addTarget(self, action: #selector(didTap(_:)), for: .touchUpInside)
}
#objc func didTap(_ sender: Any?) -> Void {
let vcA = ViewControllerA()
let navVC = UINavigationController(rootViewController: vcA)
navVC.modalPresentationStyle = .fullScreen
present(navVC, animated: true, completion: nil)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
print("viewDidAppear", NSStringFromClass(self.classForCoder))
}
}

Answer 2

Here is how it is done via Storyboard. I don't know how to do it via code. I hope it helps
In your MainViewController add this:
#IBAction func unwindToMainView(segue:UIStoryboardSegue) { }
In all otherViewController (viewController A,ViewController B,ViewController C),
Click and drag like this
Then chose the segue you added in the mainVC
Now select that segue and give it an identifier
From here you can perform segue with that identifier wherever you want. I use button to perform that segue