For apps that run in versions of iOS prior to iOS 8, the
UIAlert protocol defines the methods a delegate of a
UIAlert object should implement. The delegate implements the button actions and any other custom behavior. Some of the methods defined in this protocol are optional.
- iOS 2.0+
UIAlert is deprecated in iOS 8. (Note that
UIAlert is also deprecated.) To create and manage alerts in iOS 8 and later, use
If you add your own buttons or customize the behavior of an alert view, implement a delegate conforming to this protocol to handle the corresponding delegate messages. Use the
delegate property of an alert view to specify one of your application objects as the delegate.
If you add your own buttons to an alert view, the delegate must implement the
alert message to respond when those buttons are clicked; otherwise, your custom buttons do nothing. The alert view is automatically dismissed after the
alert delegate method is invoked.
Optionally, you can implement the
alert method to take the appropriate action when the system cancels your alert view. If the delegate does not implement this method, the default behavior is to simulate the user clicking the cancel button and closing the view.
You can also optionally augment the behavior of presenting and dismissing alert views using the methods in Customizing Behavior.