当执行逻辑：从三级页面popToRoot，切换tab页，push页面后，返回tab页时tabbar消失

[1992zhangbo]

1. Version：v1.16.0
2. Language：Objective-C
3. iOS System Version：iOS9
4. Prototype（是否是真机）：YES
5. Issue Type：Bug

1. How to repeat the problem.

页面路径如下：
CYLMineViewController -> xxxList -> xxxDetail

xxxDetail有一个按钮，点击执行如下逻辑：
//返回CYLMineViewController
[self.navigationController popToRootViewControllerAnimated:NO];
//跳转到某个tab页
AppDelegate *app = (AppDelegate *)[[UIApplication sharedApplication] delegate];
app.tabBarController.selectedIndex = 1;
//push进去一个页面
[(UINavigationController *)app.tabBarController.selectedViewController pushViewController:[xxxList new] animated:YES];

出现问题：
点击返回时，tabbar会消失。试了一下系统的tabbar，也会消失

2. Please help me in this way.

希望大神提供个解决方案，不胜感谢

3. Here is a Demo.

逻辑很简单，源码已经贴出

4. Here is my Debug log

[hongdong]

这个问题解决了吗？ @ChenYilong

[ChenYilong]

这个是v1.17.13 版本更新后的实现：

ref：5ab213b

//UIViewController+CYLTabBarControllerExtention
- (UIViewController *)cyl_popSelectTabBarChildViewControllerAtIndex:(NSUInteger)index {
   UIViewController *viewController = [self cyl_getViewControllerInsteadOfNavigationController];
   [viewController checkTabBarChildControllerValidityAtIndex:index];
   CYLTabBarController *tabBarController = [viewController cyl_tabBarController];
   tabBarController.selectedIndex = index;
   [viewController.navigationController popToRootViewControllerAnimated:NO];
   UIViewController *selectedTabBarChildViewController = tabBarController.selectedViewController;
   return [selectedTabBarChildViewController cyl_getViewControllerInsteadOfNavigationController];
}

只需要把这两行代码的顺序调整一下就行了，像下边这样

tabBarController.selectedIndex = index;
[navigationController popToRootViewControllerAnimated:NO];

原则上，上面两行的调用顺序对效果无影响，疑似是系统bug，Xcode9 系统修改了pop的调用时机。