Using a escape function in Swift to allow the use of parameters - swift

Question

I am new to this escape function in Swift, but I follow a tutorial and I use the following function below: (the function is working for me)
static func showThreeOptions(messageText: String, titleOne:String, titleTwo: String, actionOne: #escaping () -> (Void), actionTwo: #escaping () -> (), currentView: UIViewController ) {
// create the alert
let alert = UIAlertController(title: "Alerta", message: messageText, preferredStyle: UIAlertController.Style.alert)
// add the actions (buttons)
alert.addAction(UIAlertAction(title: titleOne, style: UIAlertAction.Style.default, handler: { (alert) in
actionOne()
} ))
alert.addAction(UIAlertAction(title: titleTwo, style: UIAlertAction.Style.default, handler: { (alert) in
actionTwo()
} ))
alert.addAction(UIAlertAction(title: "Cancelar", style: UIAlertAction.Style.destructive, handler: nil))
// show the alert
currentView.present(alert, animated: true, completion: nil)
}
Now, I want to change the actionTwo() to actionTwo(number:Int),
but I don't know how to change the signature actionTwo: #escaping () -> ()
How can I change the signature
actionTwo: #escaping () -> () to allow to be able to call actionTwo(number:Int) ?
-----UPDATE-----
I create the function
actionTwo(2) and it works. Thank you #RobNapier
But there is another problem now.
I call the function
AlertActions.showThreeOptions(
messageText: "Resenha Finalizada.",
titleOne: "Marcas/Fotos",
titleTwo: "Editar",
actionOne: self.someHandlerOne,
actionTwo: self.someHandlerTwo(2),
currentView: self
)
This is the functions
func someHandlerOne() {
print("test")
}
func someHandlerTwo(_ id:Int) {
print("test2")
}
Now I get the following error when I call someHandlerTwo(_ id:Int)
Cannot convert value of type '()' to expected argument type '(Int) -> ()'
How can I fix that error?
-----UPDATE 2-----
I find out how to use a escaping function now
func notImplemented(resDado_id: Int) -> () {
print(resDado_id)
}

Answer 1

Change #escaping () -> () to #escaping (Int) -> (). Instead of something that takes no parameters, you want something that takes one.
It's a little nicer to use Void for return values that are (), like (Int) -> Void, but it means the same thing.

Answer 2

My suggestion is a different approach:
Write an extension of UIViewController and use the UIAlertAction handler signature for actionOne and actionTwo.
This is still more versatile and the UIAlertAction handler closures don't escape
extension UIViewController {
func showThreeOptions(messageText: String, titleOne:String, titleTwo: String, actionOne: ((UIAlertAction) -> Void)? = nil, actionTwo: ((UIAlertAction) -> Void)? = nil) {
// create the alert
let alert = UIAlertController(title: "Alerta", message: messageText, preferredStyle: .alert)
// add the actions (buttons)
alert.addAction(UIAlertAction(title: titleOne, style: .default, handler: actionOne))
alert.addAction(UIAlertAction(title: titleTwo, style: .default, handler: actionTwo))
alert.addAction(UIAlertAction(title: "Cancelar", style: .destructive, handler: nil))
// show the alert
self.present(alert, animated: true, completion: nil)
}
}
The closures can even be declared as functions for example
func actionOne(action : UIAlertAction) {
//
}
Edit:
You don't need to pass a parameter, you can create the handler inline and capture the id
func deleteSomething(at id: Int) {
let handler : (UIAlertAction) -> Void = { action in
db.deletarResDados(id: id)
}
showThreeOptions(messageText: "Resenha Finalizada.",
titleOne: "Marcas/Fotos",
titleTwo: "Editar",
actionOne: nil,
actionTwo: handler)
}