IQKeyboardManager 在iOS11导航栏消失的问题

问题原因：IQKeyboardManager 在获取当前顶层控制器的时候获取到了tabBarController 

解决办法： 

找到IQUIView_Hierarchy.m   修改-(UIViewController *)topMostController方法  

-(UIViewController *)topMostController
{
    NSMutableArray<UIViewController*> *controllersHierarchy = [[NSMutableArray alloc] init];
    
    UIViewController *topController = self.window.rootViewController;
    
    if (topController)
    {
        [controllersHierarchy addObject:topController];
    }
    
    while ([topController presentedViewController]) {
        
        topController = [topController presentedViewController];
        [controllersHierarchy addObject:topController];
    }
    
    UIViewController *matchController = [self viewController];
    
    while (matchController != nil && [controllersHierarchy containsObject:matchController] == NO)
    {
        do
        {
            matchController = (UIViewController*)[matchController nextResponder];
            
        } while (matchController != nil && [matchController isKindOfClass:[UIViewController class]] == NO);
    }
    
    return (UIViewController*)matchController;
}

为

-(UIViewController *)topMostController{
    
    UIViewController *rootController = [UIApplication sharedApplication].keyWindow.rootViewController;
    
    if([rootController isKindOfClass:[UITabBarController class]]){
        UITabBarController *tabBarController = (UITabBarController *)rootController;
        UINavigationController *selectController = tabBarController.selectedViewController;
        UIViewController *viewController = (UIViewController *)selectController.visibleViewController;
        while (viewController.presentedViewController) {
            viewController = (UIViewController *)viewController.presentedViewController;
        }
        
        return viewController;
    }else if ([rootController isKindOfClass:[UINavigationController class]]) {
        UINavigationController *selectController = (UINavigationController *)rootController;
        return selectController.visibleViewController;
    }else if ([rootController isKindOfClass:[UIViewController class]]) {
        return rootController;
    }  
    else{
        return nil;
    }
}