beginGeneratingDeviceOrientationNotifications()
Begins the generation of notifications of device orientation changes.
Declaration
func beginGeneratingDeviceOrientationNotifications()Discussion
You must call this method before attempting to get orientation data from the device. This method enables the device’s accelerometer hardware and begins the delivery of acceleration events to the device. The device subsequently uses these events to post orientationDidChangeNotification notifications when the device orientation changes and to update the orientation property.
You may nest calls to this method safely, but you should always match each call with a corresponding call to the endGeneratingDeviceOrientationNotifications() method.