Open specific View Controller in swift - ios

Question

I have implemented firebase notification in my app. When I click the notification i want to open specific vc. The hierarchy of vc is this,
TabBarController -> TabBarVC1 -> 1VC -> 2VC
Now, I want to go to 2VC when I click the notification. I have tried the code it goes fine but the hierarchy of VC's disturbs, when I moves there then it does not comes back. This is how i open 2VC.
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let controller = storyboard.instantiateViewController(withIdentifier: "2VC")
self.present(controller, animated: true, completion: nil)
I want it to open 2VC but its hierarchy should not be disturb.
When I click back button on 2VC than it should move back to 1VC.

Answer 1

Do this
let vc1 = // alloc vc 1
let vc2 = // alloc vc 2
let vc3 = // alloc vc 3
let nav_Controllr = // alloc UINavigationController
// Now add your previous vc in NavigationController first
nav_Controllr.viewControllers.append(vc1)
nav_Controllr.viewControllers.append(vc2)
// Now push to the vc where you wanted navigate
nav_Controllr.pushViewController(vc3, animated: true)
Now your navigation stack is like this
vc1 -> vc2 -> vc3
when you pop your controller then it always be in this flow.
vc3 => vc2 => vc1

Answer 2

To have a back button then you need to make the root vc of the tabBar a navigationController
Entry Point -> TabBar -> Tab1 -> NavigationController - > VC1 -> VC2
then use this from vc1
self.navigationController?.pushViewController(vc2, animated: true)
if you want to open it from AppDelelgate call back of notification receive then use
if let tab = self.window?.rootViewController as? UITabBarController {
let vc1 = //////
let vc2 = //////
let nav = tab.viewControllers![0] as! UINavigationController
nav.viewControllers = [vc1,vc2]
}