pass variable value by popToViewController in swift

Question

I have a variable "NameofCircle" on LocationVC ViewController and i have variable CName on this Controller i want to pass the CName value to LocationVC Controller by popToViewController. I tried below code but did not get the result.

let viewControllers = self.navigationController!.viewControllers
    for aViewController in viewControllers
    {
        if aViewController is LocationVC
        {
           let Location = LocationVC()
            Location.NameofCircle = CName
    _ = self.navigationController?.popToViewController(aViewController, animated: true)
            }
}

in here you need to go for custom protocols, or unwindsegue concept, google it once you get answer — Anbu.Karthik, Mar 08 '17 at 10:52
Go for custom protocol. You can see this here - http://stackoverflow.com/questions/39285588/how-to-pass-data-from-child-to-parent-view-controller-in-swift/39288232#39288232 — onCompletion, Mar 08 '17 at 10:59

RajeshKumar R · Accepted Answer · 2017-03-08T11:42:48.197

7

Try this.

let viewControllers = self.navigationController!.viewControllers
  for var aViewController in viewControllers
  {
  if aViewController is LocationVC
     {
        let aVC = aViewController as! LocationVC
        aVC.NameofCircle = CName
        _ = self.navigationController?.popToViewController(aVC, animated: true)
     }
  }

another choice To pass value to Root ViewController

if let   myController  = self.navigationController?.viewControllers[0] as? LocationVC
  {
    myController.NameofCircle = CName
   _ =  self.navigationController?.popToViewController(myController, animated: true)
    }

edited Mar 08 '17 at 11:42

answered Mar 08 '17 at 10:53

RajeshKumar R

15,445
2
38
70

I got this error because aViewController is a ViewController not Location VC "Value of type 'UIViewController' has no member 'NameofCircle'" – Archana SIngh Mar 08 '17 at 10:56
is this correct aViewController = aViewController as! LocationVC – Anbu.Karthik Mar 08 '17 at 10:59
@RajeshkumarR - i am not tried , but this is wrong `aViewController = aViewController as! LocationVC`, one more question , is this possible we can directly send the value in popToViewController – Anbu.Karthik Mar 08 '17 at 11:01
This way the value will not go to the parent viewController. – onCompletion Mar 08 '17 at 11:02
@Anbu.Karthik Yes. It is possible to send value in popToViewController. [See this.](http://stackoverflow.com/a/6501991/7250862) – RajeshKumar R Mar 08 '17 at 11:05
@unexpectedNil I have tried this and it worked. The value can be sent to any parent view controller without any problem. – RajeshKumar R Mar 08 '17 at 11:44
@RajeshkumarR Now its clear. I also tried with this and it seems working. Thanks :) – onCompletion Mar 08 '17 at 11:46
@Anbu.Karthik I have tried this and it worked. The value can be sent to any parent view controller without any problem. – RajeshKumar R Mar 08 '17 at 11:48
1

@RajeshkumarR - if it is safer , it will go , ok one more question it will work in reverse engineering or storyboard reference concept – Anbu.Karthik Mar 08 '17 at 11:50
The question is that is it safe..?? – onCompletion Mar 08 '17 at 12:07
I got "fatal error: unexpectedly found nil while unwrapping an Optional value" on navigationController. Please help how to solve this problem. – Archana SIngh Apr 20 '17 at 09:41
@RajeshkumarR let viewControllers = self.navigationController?.viewControllers – Archana SIngh Apr 20 '17 at 09:47
Do you have navigation controller embedded in your view controller? – RajeshKumar R Apr 20 '17 at 09:50

Priyank Patel · Answer 2 · 2022-10-15T07:46:35.387

Swift 4,5

You can use with code.

 let viewControllers = self.navigationController!.viewControllers
            for aViewController in viewControllers
              {
              if aViewController is SelectDeviceToGroup
                 {
                    let selecteDevicesVc = aViewController as! SelectDeviceToGroup
                    selecteDevicesVc.isEditSelected = true
                    selecteDevicesVc.selectedDevices = self.selectedDevicesIds
                    _ = self.navigationController?.popToViewController(selecteDevicesVc, animated: true)
                 }
              }

score 0 · Answer 3 · answered Mar 08 '17 at 11:59

0

Just replace your line :

_ = self.navigationController?.popToViewController(aViewController, animated: true)

with this one:

_ = self.navigationController?.popToViewController(Location, animated: true)

answered Mar 08 '17 at 11:59

Amna Farhan

26
4

Got this Error "'Tried to pop to a view controller that doesn't exist.'" – Archana SIngh Mar 08 '17 at 12:33

pass variable value by popToViewController in swift

3 Answers3