Back button appears only after you push a ViewController
over another one.
In this image you only set the RootViewController of your NavigationController so you have nowhere to go back so that's why back button does not appear.
You can still put programatically a button that does what you need.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.