When to use new Screens in Flutter instead of TabBarView

Question

I am fairly new to Flutter and I try to understand when and why it would be necessary to navigate to a new screen. Most apps keep the same AppBar, Drawer & BottomNavigationBar (if any) through all the different "screens". Wouldn't it be easier to just have one single TabBarView, or only replace the Scaffold's body ?

I have a hard time to really understand the concept of why there needs to be a new Scaffold when routing. I couldn't find anything helpful in the official Flutter doc, even the Cookbook show you a Navigation example with 2 completely new screens just to show a different Text widget inside the Scaffold's body.

Also, what about the efficiency of always rebuilding the whole Scaffold ?

Answer 1

When you route to new page, the previous page stored in history of navigator, so you can easily return to previos page just clicking Back button. In principle all depends on what you need. You may use new page with its own Scaffold as well as one page with single Scaffold and different body widgets. For last case you need to controll Back button manually so this way is enough expensive in development.