swift resource

https://developer.apple.com/swift/resources/

TabBarController
https://developer.apple.com/documentation

sample and code
https://developer.apple.com/library/content/navigation/

started develop iOS by swift
https://developer.apple.com/library/content/referencelibrary/GettingStarted/DevelopiOSAppsSwift/index.html#//apple_ref/doc/uid/TP40015214


https://developer.apple.com/library/content/documentation/WindowsViews/Conceptual/ViewControllerCatalog/Chapters/TabBarControllers.html