CODEWITHSUNDEEP
iosswiftfunctiondebuggingcrash
Carlo Maryska
Carlo Maryska

Reputation: 1

Loading function from another Class crashes in Swift IOS

I want to load the function checkStatus() (which is part of my ViewController1) from my ViewController 2 before the Navigation Controller pops back to the ViewController1. Unfortunately, when calling the function, the app crashes as soon as it loads and I am really frustrated becaue I do not know what I did wrong.

The ViewControllers are embeded in a Navigation Controller.

Code in ViewController1:

func checkStatus(){
/* setting Label texts (Outlets) to a specific value but it is 
irrelevant as the compiler does not even get to 
    this point. The program crashes as soon as the function is called (tried it with prints).*/

Code in ViewController2:

@IBAction func didTapBack(_ sender: UIButton){
// first the function is animating something inside the VC2
ViewController1().checkStatus() // function gets called here
self.navigationController?.popToRootViewController(animated: false)
}

I am grateful for any kind of help.

Upvotes: 0

Views: 192

Answers (1)

Vivek Radadiya
Vivek Radadiya

Reputation: 171

You can use Delegate Pattern to call a function in your case.

ViewController code:

import UIKit

class ViewController: UIViewController, SecondViewControllerDelegate {

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view.
    
}

@IBAction func gotoSecondVC(_ sender: UIButton) {
    
    let secondVC = self.storyboard?.instantiateViewController(identifier: "SecondViewController") as! SecondViewController
    secondVC.delegate = self
    self.navigationController?.pushViewController(secondVC, animated: true)
    
}

func checkStatus() {
    print("\(#function) called...")
}

}

SecondViewController code:

import UIKit

protocol SecondViewControllerDelegate: class {
    func checkStatus()
}

class SecondViewController: UIViewController {

    weak var delegate: SecondViewControllerDelegate?

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }

    @IBAction func backButtonTapped(_ sender: UIButton) {
        delegate?.checkStatus()
        self.navigationController?.popViewController(animated: true)
    }

}

Upvotes: 1

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