What is the main concept behind the implementation of the Navigation library?

The main concept of the Navigation library in Android is managing navigation between screens (fragments or activities) through a centralized navigation graph.

Navigation is implemented as a declarative state graph, where each node is a screen, and edges are transitions between them. This allows:

• Defining routes and transitions in one place
• Automatically handling the navigation stack
• Simplifying data transfer between screens
• Ensuring consistent navigation behavior in the app

The Navigation Component uses NavController to manage transitions and NavHostFragment to display the current screen.

Example of using NavController:

findNavController().navigate(R.id.action_firstFragment_to_secondFragment)

Thus, the Navigation library is built on the idea of declarative navigation description and centralized transition management.