屏幕旋转

/// 跟控制器是UINavigationController
/// 是否允许转屏
- (BOOL)shouldAutorotate {
    return YES;
}

/// 支持的方向
- (UIInterfaceOrientationMask)supportedInterfaceOrientations {
    return [self.viewControllers.lastObject supportedInterfaceOrientations];
}
/// 模态时的方向
- (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
    return self.topViewController.preferredInterfaceOrientationForPresentation;
}

 1 /// 跟控制器是UITabBarController时
 2 - (BOOL)shouldAutorotate
 3 {
 4     return YES;
 5 }
 6 
 7 - (UIInterfaceOrientationMask)supportedInterfaceOrientations {
 8     return ((UINavigationController *)self.selectedViewController).topViewController.supportedInterfaceOrientations;
 9 }
10 
11 - (UIInterfaceOrientation)preferredInterfaceOrientationForPresentation {
12     return ((UINavigationController *)self.selectedViewController).topViewController.preferredInterfaceOrientationForPresentation;
13 }