Notification Center is a feature in iOS and OS X that provides an overview of alerts from applications. It displays notifications until the user completes an associated action, rather than requiring instant resolution. Users may choose what applications appear in Notification Center, and how they are handled. Initially released alongside iOS 5 in October 2011, Notification Center was made available on Mac as part of OS X Mountain Lion in July 2012.
Tweet Button]] Notification Center was released in iOS 5 to replace the previous system for dealing with push notifications. Instead of interrupting the user with a dialog box, Notification Center instead displays an alert an alert at the top of the screen. This allows the user to continue using their device, and disappears after a set period of time. All previous notifications are collated into the Notification Center itself, a panel that can be dragged down from the menu bar in iOS, or by swiping from right to left in OS X. Notifications stored in the panel may be selected by the user, thereby redirecting them to the application that initially created the notification, and marking that alert as read. Once a notification is read, it is removed from the panel. Users may also remove notifications without reading them by deleting single alerts, or dismissing all from a certain application. When an iOS device is locked, new notifications appear on the lock screen, and users may access the relevant application by swiping their finger from left to right along the notification.
Notification Center on iPhone and iPod Touch also includes Weather and Stocks widgets, displaying information on the weather at the user's current location, and any stocks that the user has selected in the Stocks application. This feature is not available on iPad or OS X. In OS X, users can select the option to display a Twitter button, allowing them to tweet directly from Notification Center. This feature will also be included in iOS 6, along with a Facebook button. The latter of these features will be available to OS X users in the fall.
Any application that uses the Push Notifications system provided by Apple may use Notification Center. OS X applications may only use this system if they are downloaded from the Mac App Store. Users may customise what they want to appear in Notification Center, and may opt to stop certain applications appearing in the center, or sending alerts to their screen. OS X users may also disable alerts and banners for a day, stopping notifications interrupting appearing on the screen. However, any notifications sent during this time are still visible in the Notification Center panel. This feature will also be released as part of iOS 6, under the banner Do Not Disturb.