How to create UIAlertView in Swift
Swift is an open-source general-purpose programming language created by Apple Inc. to develop iOS applications. The UIAlertView class is an iOS class that shows alert messages with a title, message, and one or more buttons to interact with the user.
Note: The
UIAlertViewclass has been deprecated in favor ofUIAlertControllersince iOS 8.0.
Code for UIAlertView in Swift
To display a simple alert in Swift, we can create an instance of UIAlertView in the UIViewController class, as shown in the following example:
Button("Show alert") {// Instantiating UIAlertViewlet alert = UIAlertView(title: "Simple Alert", message: "This is an example of a simple alert message.", delegate: MyViewController.self, cancelButtonTitle: "Cancel")alert.addButton(withTitle: "Ok")//Showing the UIAlertViewalert.show()}func alertView(_ alertView: UIAlertView, clickedButtonAt buttonIndex: Int) {if buttonIndex == alertView.cancelButtonIndex {print("Clicked cancel")} else {print("Clicked ok")}}
Explanation
- Lines 1–8: Defines a UI button to launch the
UIAlertView. - Lines 3–4: Defines an instance of
UIAlertViewand adds message content and buttons to the alert view for user inputs. - Line 7: Calls the
show()method to display the alert view. - Line 10: Defines an
alertView()function that takes aUIAlertViewobject and the index of the button clicked by the user as the parameter list. - Lines 11–16: Performs a check on the
buttonIndexand executes the code accordingly.
Note: Executing the code above will generate a warning stating that
UIAlertViewis deprecated and must be replaced withUIAlertController.
Code for UIAlertController in Swift
The UIAlertController class was introduced in iOS 8.0 as a replacement for UIAlertView, providing more options to display alert messages relatively easily. An example code for creating a simple alert view using Swift is shown below:
@IBAction func AlertButton(_ sender: Any) {// Instantiating UIAlertControllerlet alertController = UIAlertController(title: "Simple Alert",message: "This is an example of a simple alert message.",preferredStyle: .alert)// Handling OK actionlet okAction = UIAlertAction(title: "OK", style: .default) { (action:UIAlertAction!) inprint("Clicked OK")}// Handling Cancel actionlet cancelAction = UIAlertAction(title: "Cancel", style: .cancel) { (action:UIAlertAction!) inprint("Clicked cancel")}// Adding action buttons to the alert controlleralertController.addAction(okAction)alertController.addAction(cancelAction)// Presenting alert controllerself.present(alertController, animated: true, completion:nil)}
Explanation
- Line 1: The
AlertButtonfunction binds the user interface to the code implementation to launch the alert view. - Lines 3–6: Defines an instance of
UIAlertControllerand adds a title, message, and style to the alert view. - Lines 9–16: Defines the
UIAlertActionfor handling the input performed by the user once the alert view is displayed. - Lines 19–20: Adds the action buttons to the alert controller.
- Line 23: Displays the alert view to the user.
Output
The illustration below shows the code’s output on an iPhone 14 Pro simulator with iOS 16.4.
The following illustration shows the output of the code on the console.
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