How to Present a View Modally From UITabBarController in Swiftby
Each tab of a tab bar controller is associated with a view controller. When the user selects a specific tab, the tab bar controller displays the root view of the corresponding view controller, replacing any previous views. The tab bar interface displays tabs at the bottom for selecting between the different display views.
Tab bar controller lets us to implement easy multi-selection of displays easily. In this user interface style tabs at the bottom remains visible. Display switches between selection at child controller section above.
Comes a situation where view controller associated with a specific tab to display modally or push where Tabs at bottom gets covered behind this view controller. Instagram app is a good example where when create-post-tab is pressed, then display is opened over the tab controller.