1.获取系统Window,并设置根控制器
UIWindow *windows = [UIApplication sharedApplication].keyWindow;
windows.rootViewController = "要设置的根控制器类";
2.在appDelegate类中获取storyBoard根控制器的第一个控制器及View
[self.window.rootViewController.childViewControllers firstObject]
[[self.window.rootViewController.childViewControllers firstObject] view]