ios 获取当前ViewController

- (UIViewController*)getpresentVC:(UIWindow *)window{
    if ([window.rootViewController class]==[UITabBarController class]) {
        UITabBarController *tabBarController = (UITabBarController*)window.rootViewController;
        UINavigationController *navi = [tabBarController.viewControllers lastObject];
        NSLog(@"%d",navi.viewControllers.count);
        UIViewController *VC =[navi.viewControllers lastObject];
        if (!VC.presentedViewController) {
            return VC.presentedViewController;
        }else{
            return VC;
        }
    }else{
        return window.rootViewController;
    }
}

或者使用递归调用

- (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;
    }
}