How can present view controller from specific view controller?-CodePudding

I'm starting a navigation flow. I'm starting from AViewController and I'm navigating in app. AViewController -> BViewController -> CViewController -> DViewController. While in DViewController, I want to push EViewController. But I want AViewController to do this push, not DViewController. So I want my presentingViewController to be AViewController. With this, other ViewControllers(BViewController, CViewController, DViewController) have to be dismissed. In the last case, my navigation flow should be like this: AViewController -> EViewController. Is there a way to do this ?

CodePudding user response：

First , create a function that helps you to push A to F in Viewcontroller A

  func aToF(){
    let fVC= self.storyboard?.instantiateViewController(withIdentifier: "your vc Id") as! FViewController
   self.navigationController?.pushViewController(fVC, animated: false)
}

And where you go back to root and push F call this :

  let turnBack = self.navigationController?.viewControllers[0] as! AViewController
  self.navigationController?.popToRootViewController(animated: false)
  turnBack.aToF()

I do not recommend creating a new instance from an already memorized viewcontroller, but this is one of the easiest ways.

CodePudding user response：

do you want eviewcontroller back to Aviewcontroller, or you can push Aviewcontroller to Eviewcontroller

 func pushFrom(vc: UIViewController.Type) {
    guard let nv = self.navigationController else {
      return
   }
  for controller in nv.viewControllers as Array {
    if controller.isKind(of: vc.self) {
let eviewcontroller = Eviewcontroller()
     controller.navigationController!.pushViewController(eviewcontroller, 
 animated: true)
        break
     }
  }
}

Then

 pushFrom(vc: AViewcontroller.self)

CodePudding user response：

You need to pop all the view controller till AViewcontroller as

self.navigationController?.popToRootViewController(animated: true)

Then

self.navigationController?.pushViewController(EViewcontroller, animated: true)

Now it is AViewcontroller -> EViewcontroller

Another solution

self.navigationController?.pushViewController(EViewcontroller, animated: true)

DispatchQueue.main.asyncAfter(deadline: .now()   0.4) {
        self.navigationController?.viewControllers.remove(at: 1) // Remove B
        self.navigationController?.viewControllers.remove(at: 2) // Remove C
        self.navigationController?.viewControllers.remove(at: 3) // Remove D
}

OR Add this in EViewcontroller's viewDidAppear

self.navigationController?.viewControllers.remove(at: 1) // Remove B
self.navigationController?.viewControllers.remove(at: 2) // Remove C
self.navigationController?.viewControllers.remove(at: 3) // Remove D

CodePudding user response：

To replace the navigation stack of a view controller, use setViewControllers(_, animated:). If you pass in your existing AViewController and a new EViewController then your final navigation stack will be just those two.

There is no need to manually rebuild the stack you want by pushing and popping individual controllers.