Shows how to use a keyboard accessory view.

The application uses a single view controller. The view controller's view contains a UITextView. When you tap the text view, the view controller loads a nib file containing an accessory view that it assigns to the text view's inputAccessoryView property. The accessory view contains a button. When you tap the button, the text "You tapped me." is added to the text view. The sample also shows how you can use the keyboard-will-show and keyboard-will-hide notifications to animate resizing a view that is obscured by the keyboard.