How to transfer data between Parent and Child View Controllers

Question

I have tried looking at answers on similar questions to this, but I am not particularly experienced and have had trouble following them, so any help would be much appreciated!

Answer 1

Try This.

First Create Public Method For Add And Remove childVC.

For Add childVC.

public class func openChildViewController(parentVC:UIViewController, with childVC:UIViewController){

        parentVC.addChildViewController(childVC)
        childVC.view.frame = parentVC.view.frame
        parentVC.view.addSubview(childVC.view)
        parentVC.didMove(toParentViewController: childVC)
    }

For Remove childVC.

   public class func removeChildViewController(childVC:UIViewController){

        childVC.willMove(toParentViewController: nil)
        childVC.view.removeFromSuperview()
        childVC.removeFromParentViewController()
    }

Use Above Method.

1.ParentVC.swift

class ParentVC: UIViewController , ChildVCDelegate  {

     var arrType = NSMutableArray()

    //add ChildVC
    @IBAction func btnAddChildVC(_ sender: UIButton) {
        let ChildVC = self.storyboard?.instantiateViewController(withIdentifier: "ChildVC") as! ChildVC
        PickerVC.arrPass = arrType //for data passing create any object in ChildVC for ex. arrPass is NSMutableArray
        ChildVC.delegate = self
        openChildViewController(parentVC: self, with: ChildVC)
    }

     // MARK: ChildVC Delegate
   func SetSelectedPickerValue(strSelectOption: String) {
                print(strSelectOption)
        }
    }

}

2.ChildVC.swift

class ChildVC: UIViewController{

    // MARK: Variable for ParentVCData Passing
     var arrPass = NSMutableArray()

    override func viewWillAppear(_ animated: Bool) {
        print(arrPass)
    }

    //Remove ChildVC
    @IBAction func btnRemoveChildVC(_ sender: UIButton) {
        self.delegate?.SetSelectedPickerValue!(strSelectOption: “any String you pass ChildVC To ParentVC”)
        removeChildViewController(childVC: self)
    }
}
// MARK: Create Delegate Method
@objc protocol ChildVCDelegate{
     @objc optional func SetSelectedPickerValue(strSelectOption:String)
}