The more complex gestures, such as swipe or pinch open, are also used consistently in the built-in applications, but they are less common. In general these gestures are used as shortcuts to expedite a task, not as the only way to perform a task. When viewing a list of messages in Mail, for example, users delete a message by revealing and then tapping the Delete button in the preview row for the message. Users can reveal the Delete button in two different ways:
*Tap the Edit button in the navigation bar, which reveals a delete control in each preview row. Then, tap the delete control in a specific preview row to reveal the Delete button for that message.
*Make the swipe gesture across a specific preview row to reveal the Delete button for that message.
The first method takes an extra step, but is easily discoverable because it requires only the tap and begins with the clearly labeled Edit button. The second method is faster, but it requires the user to learn and remember the more specialized swipe gesture.
To ensure that your application is discoverable and easy to use, therefore, try to limit the gestures you require to the most familiar, that is, tap and drag. You should also avoid making one of the less common gestures, such as swipe or pinch open, the only way to perform an action. There should always be a simple, straightforward way to perform an action, even if it means an extra tap or two.
