一、获取当前控制器的上一个控制器

#pragma mark - 获取当前控制器的上一个控制器
- (UIViewController *)getLastViewController {
    NSInteger currentIndex = [self.navigationController.viewControllers indexOfObject:self];
    if(currentIndex > 0 && currentIndex < self.navigationController.viewControllers.count && currentIndex != NSNotFound) {
        // 获取上一个视图控制器
        return [self.navigationController.viewControllers objectAtIndex:currentIndex - 1];
    }
    
    return nil;
}

二、删除上一个视图控制器

#pragma mark - 将当前控制器的上一个控制器从navigationController中移除
- (void)removeLastViewControllerFromNavigationController {
    NSInteger currentIndex = [self.navigationController.viewControllers indexOfObject:self];
    if(currentIndex > 0 && currentIndex < self.navigationController.viewControllers.count && currentIndex != NSNotFound) {
        // 获取上一个视图控制器
        UIViewController *lastVC = [self.navigationController.viewControllers objectAtIndex:currentIndex - 1];
        // 删除上一个控制器（删除navigationController栈中得某一个viewController，方便跳过某一个vc而pop到更前面的vc）
        NSMutableArray *viewControllers = [[NSMutableArray alloc]initWithArray:self.navigationController.viewControllers];
        for (UIViewController *vc in viewControllers) {
            if ([vc isKindOfClass:[lastVC class]]) {
                [viewControllers removeObject:vc];
                break;
            }
        }
        self.navigationController.viewControllers = viewControllers;
    }
}

三、获取当前视图的控制器

#pragma mark - 返回当前视图的控制器
- (UIViewController *)getViewController {
    for (UIView *next = [self superview]; next; next = next.superview) {
        UIResponder *nextResponder = [next nextResponder];
        if ([nextResponder isKindOfClass:[UIViewController class]]) {
            return (UIViewController *)nextResponder;
        }
    }
    return nil;
}