Yogesh Chauhan's Blog

How to show confirmation alerts with OK and cancel buttons using Swift 5?

in Swift on March 9, 2020

We can use UIAlertController class to accomplish that.

It's an object that displays an alert message to the user.

Declaration


class UIAlertController : UIViewController

We will use this class to configure alerts and action sheets with the message that we want to display and the actions from which to choose. After configuring the alert controller with the actions and style we want, we will present it using the present(_:animated:completion:) method. UIKit displays alerts and action sheets modally over app's content.

present(_:animated:completion:)

It's an Instance Method that presents a view controller modally.

Declaration


func present(_ viewControllerToPresent: UIViewController, 
    animated flag: Bool, 
  completion: (() -> Void)? = nil)

Parameters

viewControllerToPresent: The view controller to display over the current view controller’s content.

flag: Pass true to animate the presentation; otherwise, pass false.

completion: The block to execute after the presentation finishes. This block has no return value and takes no parameters. You may specify nil for this parameter.

In addition to displaying a message to a user, we can associate actions with the alert controller to give the user a way to respond. For each action we add using the addAction(_:) method, the alert controller configures a button with the action details. When the user taps that action, the alert controller executes the block you provided when creating the action object.

addAction(_:)

It's an instance Method that attaches an action object to the alert or action sheet.

Declaration


func addAction(_ action: UIAlertAction)

Parameters

action: The action object to display as part of the alert. Actions are displayed as buttons in the alert. The action object provides the button text and the action to be performed when that button is tapped.

The following example only presents OK alert:


let alert = UIAlertController(title: "My Alert", message: "This is an alert.", preferredStyle: .alert) 

alert.addAction(UIAlertAction(title: NSLocalizedString("OK", comment: "Default action"), style: .default, handler: { _ in 
NSLog("The "OK" alert occured.")

}))

self.present(alert, animated: true, completion: nil)

One more example with OK and Cancel buttons:


let alert = UIAlertController(title: "Add title here", message: "Add your message here.", preferredStyle: UIAlertController.Style.alert)

alert.addAction(UIAlertAction(title: "OK", style: .default, handler: { (action: UIAlertAction!) in
      
       //add additional code to execute when user clicks on OK 
}))

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

       //add additional code to execute when user clicks on cancel 
}))

present(alert, animated: true, completion: nil)

Most Read

#1 How to check if radio button is checked or not using JavaScript? #2 Solution to “TypeError: ‘x’ is not iterable” in Angular 9 #3 How to add Read More Read Less Button using JavaScript? #4 How to uninstall Cocoapods from the Mac OS? #5 PHP Login System using PDO Part 1: Create User Registration Page #6 How to Use SQL MAX() Function with Dates?

Recently Posted

#Aug 15 Is PHP still good for back-end programming? #Aug 10 How to create a multisite network in WordPress? #Aug 3 How to create a circle that follows a cursor using JavaScript and CSS? #Aug 3 How to make a curtain slider using jQuery and CSS? #Aug 2 How to progressively load images and add a blurry placeholder? #Aug 1 How to create a placeholder loader (throbber) using CSS?
You might also like these
How JavaScript classes allows us to do less typing (syntactic sugar)?JavaScriptHow to Install PHP Laravel on MacOS Catalina?PHPHow to change CSS with JavaScript?CSSHow to vertically align a html radio button to it’s label?CSSA complete guide to add responsive YouTube videos using HTML and CSSCSSWhat does it mean by Continuous Integration, Continuous Delivery and Continuous Deployment?Miscellaneous