I will summarize it as my memorandum.

Introduction

This time, I will implement UIAlertController in separate files.

It is very easy to use and can be used in various situations, so please use it if you like!

Implementation

The file name can be anything, but this time I'll try to make it "Alert.swift" for clarity.

`Alert.swift`


import UIKit

final class Alert {
 //OK only alert
 static func okAlert(vc: UIViewController, title: String, message: String, handler: ((UIAlertAction) -> Void)? = nil) {
   let okAlertVC = UIAlertController(title: title, message: message, preferredStyle: .alert)
   okAlertVC.addAction(UIAlertAction(title: "OK", style: .default, handler: handler))
   vc.present(okAlertVC, animated: true, completion: nil)
 }

 // OK&Cancel alert
　static func cancelAlert(vc: UIViewController, title: String, message: String, handler: ((UIAlertAction) -> Void)? = nil) {
   let cancelAlertVC = UIAlertController(title: title, message: message, preferredStyle: .alert)
   cancelAlertVC.addAction(UIAlertAction(title: "OK", style: .default, handler: handler))
   cancelAlertVC.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
   vc.present(cancelAlertVC, animated: true, completion: nil)
 }

 //Alert with TextField
　static func textFieldAlert(vc: UIViewController, title: String, message: String, placeholder: String, securyText: Bool, handler: ((String?) -> Void)? = nil) {
   let textFieldAlertVC = UIAlertController(title: title, message: message, preferredStyle: .alert)
   textFieldAlertVC.addTextField { (textField) in
       textField.placeholder = placeholder
       textField.isSecureTextEntry = securyText
        }
   textFieldAlertVC.addAction(UIAlertAction(title: "OK", style: .default, handler: { (_) in
       handler?(textFieldAlertVC.textFields?.first?.text)
        }))
   textFieldAlertVC.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
   vc.present(textFieldAlertVC, animated: true, completion: nil)
 }

//Alerts that disappear automatically
 static func autoCloseAlert(vc: UIViewController, title: String, message: String) {
  let autoCloseAlertVC = UIAlertController(title: title, message: message, preferredStyle: .alert)
  vc.present(autoCloseAlertVC, animated: true) {
   // 1.Delete after 5 seconds
   DispatchQueue.main.asyncAfter(deadline: .now() + 1.5) {
     autoCloseAlertVC.dismiss(animated: true, completion: nil)
     }
   }
 }

How to use

The caller of the above implementation code looks like this.

`ViewController.swift`


   //Show alert for OK button only
   Alert.okAlert(vc: self, title: "OK alert", message: "Only the OK button!", handler: { (_) in
     //Describe the process when you want to do something after pressing the OK button
     print("After pressing the OK button!")
   })

   //Show alerts with OK and Cancel buttons
   Alert.cancelAlert(vc: self, title: "OK&Cancel alert", message: "There is also a cancel button!", handler: { (_) in
     //Describe the process when you want to do something after pressing the OK button
     print("After pressing the OK button!")
   })

   //OK with TextField&Show alerts with cancellations
   Alert.textFieldAlert(vc: self, title: "TextField alert", message: "You can enter characters!", placeholder: "input", securyText: false, handler: { (text) in
     //Describe the processing when using the entered characters
     print("I input it\(text)It is displayed!")
   })

  //Show alerts that disappear automatically
  Alert.autoCloseAlert(vc: self, title: "Alerts that disappear automatically", message: "It disappears automatically!")

Summary

How was it?

This is my first time writing Qiita, so I think there are many points that cannot be reached. After that, it's easier to use than the code above! If you have any implementation code, please comment! : open_hands:

Try to implement UIAlertController by separating files