In general, UIAlertViews are pretty evil. However, they can be useful in certain circumstances, like the early stages of development. This article, from the generally-pretty-awesome-and-informative site Use Your Loaf by Keith Harrison, gives an overview of some of the changes to UIAlertView in iOS 5…
UIAlertView changes in iOS 5
The UIAlertView class has been available since iOS 2. It is similar to the UIActionSheet class but generally the UIAlertView is used to display an alert message to the user whereas UIActionSheet is useful when you want the user to confirm or choose between a set of options. This post will look at some useful additions to UIAlertView in iOS 5 however that also permit the user to enter some text into the alert view.
Thanks to Dave Verwer (@daveverwer) and his iOS Dev Weekly newsletter for this one too!