寻找最外层的控制器、最上层控制器

//寻找最外层控制器
- (UIViewController *)keyVc {
    UIViewController *rootVc = [UIApplication sharedApplication].keyWindow.rootViewController;
    UIViewController *keyVc = rootVc;
    while ([keyVc presentedViewController]) {
        keyVc = [keyVc presentedViewController];
    }
    return keyVc;
}


//寻找最上层控制器
- (UIViewController*)topViewController {
    return [self topViewControllerWithRootViewController:[UIApplication sharedApplication].keyWindow.rootViewController];
}
- (UIViewController*)topViewControllerWithRootViewController:(UIViewController*)rootViewController {
    if ([rootViewController isKindOfClass:[UITabBarController class]]) {
        UITabBarController* tabBarController = (UITabBarController*)rootViewController;
        return [self topViewControllerWithRootViewController:tabBarController.selectedViewController];
    } else if ([rootViewController isKindOfClass:[UINavigationController class]]) {
        UINavigationController* nav = (UINavigationController*)rootViewController;
        return [self topViewControllerWithRootViewController:nav.visibleViewController];
    } else if (rootViewController.presentedViewController) {
        UIViewController* presentedViewController = rootViewController.presentedViewController;
        return [self topViewControllerWithRootViewController:presentedViewController];
    } else {
        return rootViewController;
    }
}