How to reload a view controller when back from another view using tab bar

Question

I have a common view used when the user opens the app (VC1). With a tab bar controller, I load another view (VC2) that can be used to update data visible in the previous one. When I go back on VC1 (which is stack), it does not reload with updated data.

I have tried to call the viewDidLoad in the viewWillAppear like so...

override func viewWillAppear(_ animated: Bool) {
    viewDidLoad()
}

It works, but it loads over the VC1 still on stack and the user can see the change (not good).

I suppose that to dismiss the VC1 would help, but I haven't found how to dismiss a view when using tab bar controller.

Answer 1

Follow these steps to handle you view load setup every time your view will appear:
(VC1 = First View Controller)

• Create a new function/method (named viewLoadSetup) in your VC1 and move all codes from viewDidLoad() to viewLoadSetup().

• Now, Call viewLoadSetup() from viewWillAppear

  class VC1: UIViewController {
  
      override func viewDidLoad() {
         super.viewDidLoad()
         // viewLoadSetup()  you may call it from view did load also
      }
  
      override func viewWillAppear(_ animated: Bool) {
         super.viewWillAppear(animated)
         viewLoadSetup()
  
      }
  
  
       func viewLoadSetup(){
        // setup view did load here
       }
  
  
  }
  

If you want to call viewLoadSetup from viewDidLoad for one time, when your view controller is loaded, and then after every time from your viewWillAppear then,

class VC1: UIViewController {

    var isLoadingViewController = false

    override func viewDidLoad() {
        super.viewDidLoad()
        isLoadingViewController = true
        viewLoadSetup()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        if isLoadingViewController {
            isLoadingViewController = false
        } else {
            viewLoadSetup()
         }
    }


    func viewLoadSetup(){
      // setup view did load here
    }


}

Answer 2

You could use block in VC2 to call back VC1 to reload something.
First, in VC2, declare a block:

class View2Controller: UIViewController {

    public var completionHandler:(()->Void)?
    //...
}

Second, make callback in VC2 before going back:

self.completionHandler?()

Finally, in VC1, you are able to be called back to reload:

let vc2 = View2Controller()
vc2.completionHandler = { [weak self] () -> Void in
    //call reloading method like: self?.reloadData()
}