Passing data between controllers ABC, from C to 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.

self.navigationController?.popToRootViewController(animated: true) — Jay Patel, Feb 22 '18 at 09:28
If you want to pass data with delegate from c-> a then you can create two protocols one will pass data from c->b and other will pass data from b->a. Why? Because your A has ref of B not of C (A is pushing B); so you can't directly call delegate from c->a — Prashant Tukadiya, Feb 22 '18 at 09:40
Use this [link](https://stackoverflow.com/a/15839298/5391914) for unwinding to your A view controller — Hamed, Feb 22 '18 at 09:49

score 1 · Accepted Answer · edited Feb 22 '18 at 10:35

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.

edited Feb 22 '18 at 10:35

CZ54

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answered Feb 22 '18 at 09:30

Saad Chaudhry

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My actual question is about passing the data. I know about this method to pop to the controller A. – Parth Adroja Feb 22 '18 at 09:33
have a look at unwind segue. – Saad Chaudhry Feb 22 '18 at 09:33
I want to do it without using unwind segues. – Parth Adroja Feb 22 '18 at 09:34
what if you pass delegate reference of A->B then B->C? – Saad Chaudhry Feb 22 '18 at 09:39
Can you give an example how can I do it? – Parth Adroja Feb 22 '18 at 09:40
@ParthAdroja The only reason not to use unwind segues would be that you are not using storyboard. If thats the case the give delegate pattern a try. Here is an [example](https://medium.com/@jamesrochabrun/implementing-delegates-in-swift-step-by-step-d3211cbac3ef) – Skywalker Feb 22 '18 at 09:43
This could be a workaround, not sure how well it will work. BClass *bVC = [[BClass alloc] init]; bVC .Adelegate = self; and then moving to C. CClass *cVC = [[CClass alloc] init]; cVC .delegate = Adelegate ; something like that. – Saad Chaudhry Feb 22 '18 at 09:46
@ParthAdroja Updated to allow you to send data from C to A – CZ54 Feb 22 '18 at 10:35

score 0 · Answer 2 · answered Jul 06 '20 at 14:19

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)
        }
    }

score -3 · Answer 3 · answered Feb 22 '18 at 09:46

-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

answered Feb 22 '18 at 09:46

Asim Iftikhar Abbasi

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No, Singleton are really not design for that. – CZ54 Feb 22 '18 at 10:36
then what is suitable for passing data?? @CZ54 – Asim Iftikhar Abbasi Feb 22 '18 at 10:39
1

You can either use the Delegate pattern or you can look through NavigationController stack, as suggested above. What if you go again to C after A ? You are stucked with your singleton :) – CZ54 Feb 22 '18 at 10:47
how can I stucked when I go again C After A?? @CZ54 – Asim Iftikhar Abbasi Feb 22 '18 at 10:51
1

The Singleton will contains old values – CZ54 Feb 22 '18 at 12:17

Passing data between controllers ABC, from C to A

3 Answers3