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Kevtho
Asked: 2020-06-01 19:53:55 +0800 CST 2020-06-01 19:53:55 +0800 CST

dynamically fill action sheet Swift 3

  • 772

I am looking for a way to make a floating list (TableView inside AlertView) with data from a list of objects and that when clicking on an element gives me the reference to the selected object.

For this I am using an action sheet and a for loop as follows

@IBAction func btnVerLista_onClick(_ sender: Any) {
        let alertController = UIAlertController(title: "Action Sheet", message: "Lista de Superheroes", preferredStyle: .actionSheet)

        for item in arrSuperHeroes{

            let superbutton = UIAlertAction(title: (item as! SuperHeroe).nombre , style: .default, handler: { (action) -> Void in
                self.superSel = item as! SuperHeroe
                print(self.superSel.nombre)
        })
        alertController.addAction(superbutton)
        }

        self.navigationController!.present(alertController, animated: true, completion: nil)
    }

But I always have this error when executing the last line

fatal error: unexpectedly found nil while unwrapping an Optional value (lldb)

Could someone help me with the idea of ​​the error or if there is another way to do what I need.

ios

1 Answers

  1. Best Answer

    The last line of the code looks like this:

    self.navigationController!.present(alertController, animated: true, completion: nil)

    More context would be missing but it gives the impression that navigationControllerit is indeed nilwhy the error occurs. However, it is not necessary to use navigationControllerto invoke the method present, in this particular case, you can do it over self.

    The complete code would look like this:

    class ViewController: UIViewController {

    private var héroes = ["Spiderman", "Superman", "Batman", "Sam Fisher", "Pikolín"]

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    @IBAction func héroesPresionado(_ sender: UIButton) {
        let sheet = UIAlertController(title: "Héroes", message: "Selecciona un héroe", preferredStyle: .actionSheet)

        for héroe in self.héroes {
            sheet.addAction(UIAlertAction(title: héroe, style: .default, handler: { (action: UIAlertAction) in
                print("Seleccionaste a: \(héroe)")
            }))
        }

        self.present(sheet, animated: true) {
        }
    }
}

    The app looks like this:

    enter image description here

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