How can I output UIAlertController to a separate file and output data from there? - swift

Question

I'm trying to output alert to a separate function, since there will be many similar ones.
Here is my alert:
extension UIViewController {
func alertEditSum(nameCell: String, completion: (() -> Void)) {
let alertController = UIAlertController(title: "Hello", message: "", preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "Save", style: .default , handler: { _ in
let nameFolderField = alertController.textFields![0] as UITextField
if nameFolderField.isTextFieldCheck(text: nameFolderField.text!) == true {
// -----here----
}
}))
alertController.addAction(UIAlertAction(title: "Cancel"
, style: .cancel, handler: nil))
alertController.addTextField(configurationHandler: { (nameField: UITextField!) -> Void in
nameField.clearButtonMode = .always
nameField.keyboardType = .decimalPad
})
self.present(alertController, animated: true)
}
}
and my piece of code is in another VC:
self.sortedDate[indexPath.section-1].personPayment = Double(nameFolderField.text!)!
do {
try! self.context.save()
collectionView.reloadData()
}
The problem is that I need to consider what exactly the user enters in UITextField. text! (nameFolderField.text!). I also can't add completion to the alert code, writes an error.
Completion should be added to the line where it says: / / - - - - - here----
Please tell me how to solve this problem?

Answer 1

This should do the trick:
func alertEditSum(nameCell: String, completion: #escaping ((String?) -> Void)) {
let alertController = UIAlertController(title: "Hello", message: "", preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "Save", style: .default, handler: { _ in
let nameFolderField = alertController.textFields![0] as UITextField
if nameFolderField.isTextFieldCheck(text: nameFolderField.text!) == true {
completion(nameFolderField.text)
}
}))
alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { _ in
completion(nil)
}))
alertController.addTextField(configurationHandler: { nameField in
nameField.clearButtonMode = .always
nameField.keyboardType = .decimalPad
})
self.present(alertController, animated: true)
}
To call it:
theViewController.alertEditSum(nameCell: "text") { text in
if let text = text {
//Do stuff
} else { //Text is invalid or user has cancel
}
}
Now, isTextFieldCheck(text:) is I guess a method on UITextField, since it's checking its own text, why giving it as a parameter?
Why not just func isTextValid()?
I would also avoid the force unwrap: !.
Going further, would be to use Result<String, Error> in the completion:
completion((Result<String, Error>) -> Void)) to have more infos if needed (user has canceled, text wasn't not valid for any reason, etc.)

Answer 2

You neeed #escaping completion to send value from inside a closure to a caller , Main changes completion:#escaping (String?) -> Void) and completion(nameFolderField.text)
extension UIViewController {
func alertEditSum(nameCell: String,completion:#escaping (String?) -> Void) {
let alertController = UIAlertController(title: "Hello", message: "", preferredStyle: .alert)
alertController.addAction(UIAlertAction(title: "Save", style: .default , handler: { _ in
let nameFolderField = alertController.textFields!.first!
if nameFolderField.isTextFieldCheck(text: nameFolderField.text!) {
completion(nameFolderField.text)
}
}))
alertController.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
alertController.addTextField(configurationHandler: { (nameField: UITextField!) -> Void in
nameField.clearButtonMode = .always
nameField.keyboardType = .decimalPad
})
self.present(alertController, animated: true)
}
}
Call
alertEditSum(nameCell:<#SomeValue#>) { result in
print(result)
}