How would I create a UIAlertView in Swift?

**on IOS 9, you can do this**

let alert = UIAlertController(title: "Alert", message: "Message", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Click", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated: true, completion: nil)

For **SWIFT4**, I think, extending `UIViewController` and creating a reusable confirmation control is the most elegant way.

You can extend the `UIViewController` as below:

extension UIViewController {

func AskConfirmation (title:String, message:String, completion:@escaping (_ result:Bool) -> Void) {
let alert = UIAlertController(title: title, message: message, preferredStyle: UIAlertControllerStyle.alert)
self.present(alert, animated: true, completion: nil)

alert.addAction(UIAlertAction(title: "Ok", style: .default, handler: { action in
completion(true)
}))

alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { action in
completion(false)
}))
}
}

Then you can use it anytime:

AskConfirmation(title: "YOUR MESSAGE TITLE", message: "YOUR MESSAGE") { (result) in
if result { //User has clicked on Ok

} else { //User has clicked on Cancel

}
}

let alertController = UIAlertController(title: "Select Photo", message: "Select atleast one photo", preferredStyle: .alert)
let action1 = UIAlertAction(title: "From Photo", style: .default) { (action) in
print("Default is pressed.....")
}
let action2 = UIAlertAction(title: "Cancel", style: .cancel) { (action) in
print("Cancel is pressed......")
}
let action3 = UIAlertAction(title: "Click new", style: .default) { (action) in
print("Destructive is pressed....")

}
alertController.addAction(action1)
alertController.addAction(action2)
alertController.addAction(action3)
self.present(alertController, animated: true, completion: nil)

}

// UIAlertView is deprecated. Use UIAlertController
// title = title of the alert view.
// message = Alert message you want to show.
// By tap on "OK" , Alert view will dismiss.

UIAlertView(title: "Alert", message: "Enter Message here.", delegate: nil, cancelButtonTitle: "OK").show()

try This.
Put Bellow Code In Button.


let alert = UIAlertController(title: "Your_Title_Text", message: "Your_MSG", preferredStyle: UIAlertControllerStyle.alert)
alert.addAction(UIAlertAction(title: "Your_Text", style: UIAlertActionStyle.default, handler: nil))
self.present(alert, animated:true, completion: nil)

Below is the reusable code for alert view and action sheet, Just write one line to show alert anywhere in application

class AlertView{

static func show(title:String? = nil,message:String?,preferredStyle: UIAlertControllerStyle = .alert,buttons:[String] = ["Ok"],completionHandler:@escaping (String)->Void){
let alert = UIAlertController(title: title, message: message, preferredStyle: preferredStyle)

for button in buttons{

var style = UIAlertActionStyle.default
let buttonText = button.lowercased().replacingOccurrences(of: " ", with: "")
if buttonText == "cancel"{
style = .cancel
}
let action = UIAlertAction(title: button, style: style) { (_) in
completionHandler(button)
}
alert.addAction(action)
}

DispatchQueue.main.async {
if let app = UIApplication.shared.delegate as? AppDelegate, let rootViewController = app.window?.rootViewController {
rootViewController.present(alert, animated: true, completion: nil)
}

}
}
}



**Usage :**

class ViewController: UIViewController {

override func viewWillAppear(_ animated: Bool) {
AlertView.show(title: "Alert", message: "Are you sure ?", preferredStyle: .alert, buttons: ["Yes","No"]) { (button) in
print(button)
}
}

}

SWIFT 4 : Simply create a extension to UIViewController as follows:

extension UIViewController {
func showSuccessAlert(withTitle title: String, andMessage message:String) {
let alert = UIAlertController(title: title, message: message,
preferredStyle: UIAlertController.Style.alert)
alert.addAction(UIAlertAction(title: "OK".localized, style:
UIAlertAction.Style.default, handler: nil))
self.present(alert, animated: true, completion: nil)
}
}

Now in your ViewController, directly call above function as if they are provided by UIViewController.

yourViewController.showSuccessAlert(withTitle:
"YourTitle", andMessage: "YourCustomTitle")

You can use this simple extension with **n number** of buttons and associated actions swift4 and above

extension UIViewController {
func popupAlert(title: String?, message: String?, actionTitles:[String?], actions:[((UIAlertAction) -> Void)?]) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .alert)
for (index, title) in actionTitles.enumerated() {
let action = UIAlertAction(title: title, style: .default, handler: actions[index])
alert.addAction(action)
}
self.present(alert, animated: true, completion: nil)
}
}




you can use it like ,

self.popupAlert(title: "Message", message: "your message", actionTitles: ["first","second","third"], actions:[
{action1 in
//action for first btn click
},
{action2 in
//action for second btn click
},
{action3 in
//action for third btn click
}, nil])

#One Button

[![One Button Screenshot][1]][1]

class ViewController: UIViewController {

@IBAction func showAlertButtonTapped(_ sender: UIButton) {

// create the alert
let alert = UIAlertController(title: "My Title", message: "This is my message.", preferredStyle: UIAlertController.Style.alert)

// add an action (button)
alert.addAction(UIAlertAction(title: "OK", style: UIAlertAction.Style.default, handler: nil))

// show the alert
self.present(alert, animated: true, completion: nil)
}
}

#Two Buttons

[![Two Button Alert Screenshot][2]][2]

class ViewController: UIViewController {

@IBAction func showAlertButtonTapped(_ sender: UIButton) {

// create the alert
let alert = UIAlertController(title: "UIAlertController", message: "Would you like to continue learning how to use iOS alerts?", preferredStyle: UIAlertController.Style.alert)

// add the actions (buttons)
alert.addAction(UIAlertAction(title: "Continue", style: UIAlertAction.Style.default, handler: nil))
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))

// show the alert
self.present(alert, animated: true, completion: nil)
}
}

#Three Buttons

[![enter image description here][3]][3]

class ViewController: UIViewController {

@IBAction func showAlertButtonTapped(_ sender: UIButton) {

// create the alert
let alert = UIAlertController(title: "Notice", message: "Lauching this missile will destroy the entire universe. Is this what you intended to do?", preferredStyle: UIAlertController.Style.alert)

// add the actions (buttons)
alert.addAction(UIAlertAction(title: "Remind Me Tomorrow", style: UIAlertAction.Style.default, handler: nil))
alert.addAction(UIAlertAction(title: "Cancel", style: UIAlertAction.Style.cancel, handler: nil))
alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: nil))

// show the alert
self.present(alert, animated: true, completion: nil)
}
}

#Handling Button Taps

The `handler` was `nil` in the above examples. You can replace `nil` with a [closure][5] to do something when the user taps a button. For example:

alert.addAction(UIAlertAction(title: "Launch the Missile", style: UIAlertAction.Style.destructive, handler: { action in

// do something like...
self.launchMissile()

}))

#Notes

- Multiple buttons do not necessarily need to use different `UIAlertAction.Style` types. They could all be `.default`.
- For more than three buttons consider using an Action Sheet. The setup is very similar. [Here is an example.][6]


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[5]:

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**SwiftUI** on Swift 5.x and Xcode 11.x

```swift
import SwiftUI

struct ContentView: View {

@State private var isShowingAlert = false

var body: some View {
VStack {
Button("A Button") {

self.isShowingAlert.toggle()
}
.alert(isPresented: $isShowingAlert) { () -> Alert in
Alert(
title: Text("Alert"),
message: Text("This is an alert"),
dismissButton:
.default(
Text("OK"),
action: {
print("Dismissing alert")
}
)
)
}

}
.padding()
}
}

struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
```