Search code examples
iosswiftuinavigationcontrollerseguexcode-storyboard

How to start from a non-initial NavigationController scene

I'm trying to mimic the navigation logic in Apple default app "Photos". Below is the illustration of the app navigation logic.

enter image description here

When you first start the app, you land on "Moments" view which is at the third highest hierarchy level in the app. It's quite interesting because the whole "Photos" tab seems like to be embedded into a single NavigationController.

However, if all scenes are embedded into a single NavigationController how do you start from a non-initial scene?

Here's my hackish implementation without embedding scenes into any NavigationController(all the segues are presented as show: enter image description here

It results the behavior I wanted but I'm not sure about the memory issue. Am I allocating new VCs every loop? And the storyboard just doesn't look right.

As an answer, a simple Storyboard capture with brief explanation would be nice.

Solution

  • As I said in my comments you need to modify the .viewControllers property of your UINavigationController you can do this using setViewControllers(_:animated:) method or modifying directly .viewControllers property where rootViewController will be the viewControllersArray[0] and topViewController will be viewControllersArray[count-1]

    This property description and details can be founded in the UINavigationController documentation

    viewControllers

    Property

    The view controllers currently on the navigation stack.

    Declaration SWIFT

    var viewControllers: [UIViewController]

    Discussion The root view controller is at index 0 in the array, the back view controller is at index n-2, and the top controller is at index n-1, where n is the number of items in the array.

    Assigning a new array of view controllers to this property is equivalent to calling the setViewControllers:animated: method with the animated parameter set to false.

    example

        let storyboard = UIStoryboard(name: "Main", bundle: Bundle.main)
    let firstViewController = storyboard.instantiateViewController(withIdentifier: "FirstViewController") as? FirstViewController
    let secondViewController = storyboard.instantiateViewController(withIdentifier: "SecondViewController") as? SecondViewController
    let thirdViewController = storyboard.instantiateViewController(withIdentifier: "ThirdViewController") as? ThirdViewController

    self.navigationController?.setViewControllers([firstViewController,secondViewController,thirdViewController], animated: false)