Do I need to create a separate activity for each screen?

Question

Android

When creating a project in android with a preset menu, a project is created with one activity and with several fragments for each menu item.
If I myself try to add a new fragment + viewmodel combination, then android studio also creates another activity in addition.

I'm just starting to dive into android development and it's still not entirely clear.

Answer 1

No, it doesn `t need. There should be one activity. There is one fragment per screen.

Answer 2

It is possible on activity, it is possible on fragments, the main thing is to understand the difference, and why it is better on fragments.

Answer 3

there is a good principle - a separate activity is started when it can be used as a standalone application,
for example - a calculator as part of an application can be designed as a separate activity and available for calling by third-party applications