Passing data to previous ViewController Swift .

We will pass data from class second back to ViewController.swift.

In class second, we want to pass a string get from textfield to ViewController.

In ViewController.swift, add this text to class declaration.

DataEnteredDelegate

Copy this function to above last close bracket.

func setback(info: String){

      la.text = info

  }

This function receive string pass back and set to Label la.

Add this line in function of button to open second viewcontroller.

vc.delegate = self

func next(sender: UIButton){

        let vc = second()

       vc.passingtext = text

    vc.delegate = self

  self.presentViewController(vc, animated: true, completion: nil)

    }

In class second, copy to below import.

protocol DataEnteredDelegate: class {

    func setback(info: String)

}

Add this line to below class open bracket.

weak var delegate: DataEnteredDelegate? = nil

We will get string from Textfield and pass back, function for back button like this.

let year = textfield.text

        if(year == ""||year == " "){

            toast("Please enter the year")

        }

        else{

            self.delegate?.setback(year!)

            self.dismissViewControllerAnimated(true, completion: nil)

            }

We get string from textField, check if it blank, show inform to user, if not blank, pass to previous ViewController by call setback function. Need to use protocol on top of class.

Run ro see result.