How to accept function as a parameter in function - swift

Question

I need to accept function as a parameter after accepting function I want that function to be done on viewcontroller with self code below for better understanding
private func addSwipeControllerLeft(name: String, color: UIColor) -> UISwipeActionsConfiguration {
let action = UIContextualAction(
style: .normal,
title: name
) { [weak self] (action, view, completionHandler) in
self?.handleMarkAsFavourite() // I need to create function with accepts another function as a parametre
completionHandler(true)
}
}
I tried generics but it returns an error Value of type 'FeedViewController' has no member 'T'
private func addSwipeControllerLeft2<T>(name: String, color: UIColor, pFunction: T) -> UISwipeActionsConfiguration {
let action = UIContextualAction(
style: .normal,
title: name
) { [weak self] (action, view, completionHandler) in
self?.T
completionHandler(true)
}
}
any solutions ?

Answer 1

There is no need for a generic Type here. Add your desired function signature to addSwipeControllerLeft2s signature and call it inside your closure.
// declare the signature here
private func addSwipeControllerLeft2(name:String,color:UIColor, pFunction: #escaping ()->Void) -> UISwipeActionsConfiguration{
let action = UIContextualAction(style: .normal, title: name) { [weak self] (action, view, completionHandler) in
pFunction() // invoke it here
completionHandler(true)
}
}
you could call it this way:
private func TestFunc(){
}
func TestAddSwipe(){
// you can pass any function to pFunction: you want as long as it
// satisfies the signature ()->Void
addSwipeControllerLeft2(name: "", color: .red, pFunction: TestFunc)
}

Answer 2

Calling a passed function on self cannot be done in this way, but if you pass the ViewController function as a parameter, it will be called on self:
class ViewController: UIViewController {
private func addSwipeControllerLeft2(name: String, color: UIColor, function: #escaping () -> Void) -> UISwipeActionsConfiguration{
let action = UIContextualAction(style: .normal,
title: name) { (action, view, completionHandler) in
function()
completionHandler(true)
}
return UISwipeActionsConfiguration(actions: [action])
}
private func handleMarkAsFavourite() {
print("Called on", self)
}
}
Example:
addSwipeControllerLeft2(name: "Test", color: .red, function: self.handleMarkAsFavourite)