在控制器 ABC 之间传递数据，从 C 到 A

Question

Consider three different controllers A, B and C where A is initial controller in Navigation Controller.

Now I push to B and then push to C.

A --> B --> C

Then I want to go from C to A. How can I go there with a single push and animation. I guess the way would be finding the controller A from the navigation stack and call popToController method. Let me know If any other better way.

Now main question is how can I pass the data from C --> A . If it's from B --> A I could use the delegation. But for C --> A what could be done to use the delegation?

I do have workaround by using observer, singleton, reactive patterns. But I would like to know if any better way can be used.

Answer 1

You can have multiple ways to achieve this functionality. Once can be get you VC from list and pop to it.

let viewControllers: [UIViewController] = self.navigationController!.viewControllers ;
    for aViewController in viewControllers {
        if let controllerA =  aViewController as? AViewController) {
           controllerA.data = self.data               
           self.navigationController?.popToViewController(controllerA, animated: true);
        }
    }

Also you might be interested in unwind segue . Here is a nice example too.

Answer 2

You can achieve this via this approach, it will work 100%

for item in self.navigationController?.viewControllers ?? [UIViewController]() {
        if item is FirstVC, let vc = item as? FirstVC {
            vc.data = ThirdVC.data //3rd vc data assign to 1st vc
            vc.callAnyMethodOfFirstVC()
            self.navigationController?.popToViewController(item, animated: true)
        }
    }

Answer 3

For passing data from C --> A use singleton pattern. any data you want to pass save in variable using singleton pattern and then use

 self.navigationController?.popToRootViewController(animated: true)

and now you can access data where you want. hope its help