iOS9支持的InterfaceDirectionsforWindow停止调用

我想在横向模式下显示1或2个UIViewController，而在纵向模式下显示其他UIViewController。 为此，我在AppDelegate中实现了这个函数

-(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
{
    return self.orientation;
}

其中，在AppDelegate.h中，方向为：

@property (nonatomic, assign) UIInterfaceOrientationMask orientation;

在UIViewcontroller中，我需要横向定位。我把这个密码

-(void)viewWillAppear:(BOOL)animated
{
    self.appDelegate.orientation = UIInterfaceOrientationMaskLandscape;
}

及

---

但是，当我转到“LandscapeViewController”时，它工作正常，我返回，它工作正常，我再次转到“LandscapeViewController”它工作正常，然后当我返回时，SupportedInterfaceDirectionsforWindow方法停止调用。有什么原因吗？或者我正在做一些奇怪的事情？

如果您正在使用UITabBarController，请为UITabBarController创建一个自定义类，并将此代码放在那里

-(UIInterfaceOrientationMask) supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskPortrait;
}

并根据需要将其放置在视图控制器中

将此代码放在appDelegate中

-(UIInterfaceOrientationMask)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
{

    return UIInterfaceOrientationMaskPortrait | UIInterfaceOrientationMaskLandscapeLeft | UIInterfaceOrientationMaskLandscapeRight;

    id rootViewController = [self topViewControllerWithRootViewController:window.rootViewController];

    if (rootViewController != nil)
    {
        if ([rootViewController respondsToSelector:@selector(canRotate)])
        {
            return UIInterfaceOrientationMaskLandscape;
        }
    }
    return UIInterfaceOrientationMaskPortrait;
}

-(UIViewController*) topViewControllerWithRootViewController:(id)rootViewController
{

    if (rootViewController == nil)
    {
        return nil;
    }

    if ([rootViewController isKindOfClass:[UITabBarController  class]])
    {
        UITabBarController *selectedTabBarController = rootViewController;
        return [self topViewControllerWithRootViewController:selectedTabBarController.selectedViewController];
    }
    else if ([rootViewController isKindOfClass:[UINavigationController class]])
    {
        UINavigationController *selectedNavController = rootViewController;
        return [self topViewControllerWithRootViewController:selectedNavController.visibleViewController];
    }
    else
    {
        UIViewController *selectedViewController = rootViewController;
        if (selectedViewController.presentedViewController != nil)
        {
            return [self topViewControllerWithRootViewController:selectedViewController.presentedViewController];
        }
    }
    return rootViewController;
}

并将其放置在视图控制器中

-(void)canRotate
{

}

-(void)canRotate
{

}