获取顶层视图控制器UIViewController

+ (UIViewController *)getCurrentVC
{
UIViewController *RootVC = [UIApplication sharedApplication].keyWindow.rootViewController;
UIViewController *currentVC = RootVC;
while (currentVC.presentedViewController) {
currentVC = currentVC.presentedViewController;
}
return currentVC;
}

func getCurrentVC()-> UIViewController? {
var RootVC = UIApplication.sharedApplication().keyWindow?.rootViewController
while RootVC?.presentedViewController != nil {
RootVC = RootVC?.presentedViewController
}
return RootVC
}