Class

UIAlertController

An object that displays an alert message to the user.

Declaration

@interface UIAlertController : UIViewController

Overview

Use this class to configure alerts and action sheets with the message that you want to display and the actions from which to choose. After configuring the alert controller with the actions and style you want, present it using the presentViewController:animated:completion: method. UIKit displays alerts and action sheets modally over your app's content.

In addition to displaying a message to a user, you can associate actions with your alert controller to give the user a way to respond. For each action you 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. Listing 1 shows how to configure an alert with a single action.

Listing 1

Configuring and presenting an alert

UIAlertController* alert = [UIAlertController alertControllerWithTitle:@"My Alert"
                               message:@"This is an alert."
                               preferredStyle:UIAlertControllerStyleAlert];
 
UIAlertAction* defaultAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault
   handler:^(UIAlertAction * action) {}];
 
[alert addAction:defaultAction];
[self presentViewController:alert animated:YES completion:nil];

When configuring an alert with the UIAlertControllerStyleAlert style, you can also add text fields to the alert interface. The alert controller lets you provide a block for configuring your text fields prior to display. The alert controller maintains a reference to each text field so that you can access its value later.

Topics

Creating an Alert Controller

+ alertControllerWithTitle:message:preferredStyle:

Creates and returns a view controller for displaying an alert to the user.

Configuring the Alert

title

The title of the alert.

message

Descriptive text that provides more details about the reason for the alert.

preferredStyle

The style of the alert controller.

Configuring the User Actions

- addAction:

Attaches an action object to the alert or action sheet.

actions

The actions that the user can take in response to the alert or action sheet.

preferredAction

The preferred action for the user to take from an alert.

Configuring Text Fields

- addTextFieldWithConfigurationHandler:

Adds a text field to an alert.

textFields

The array of text fields displayed by the alert.

Constants

UIAlertControllerStyle

Constants indicating the type of alert to display.

Relationships

Inherits From

See Also

Alerts

Getting the User's Attention with Alerts and Action Sheets

Present important information to the user or prompt the user about an important choice.

UIAlertAction

An action that can be taken when the user taps a button in an alert.