您可以注册通知 UIDeviceOrientationDidChangeNotification $ c> UIDevice.h ），然后当你关心方向变化时调用这个方法：

You can register for the notification UIDeviceOrientationDidChangeNotification (from UIDevice.h), and then when you care about orientation changes call this method:

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];

当您不再关心方向更改时，请调用此方法：

When you no longer care about orientation changes, call this method:

[[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];

通知将在适当时发送，您可以检查 [UIDevice currentDevice ] .orientation ，找出当前的方向。

The notification will be sent when applicable, and you can check [UIDevice currentDevice].orientation to find out what the current orientation is.