Why is 'Up Navigation' a recommended Android guideline?

1. What is the benefit of using navigation component in Android?
2. What does navigate up mean?
3. Why the Behaviour of the back and up buttons must be different?

What is the benefit of using navigation component in Android?

Android Jetpack's Navigation component helps you implement navigation, from simple button clicks to more complex patterns, such as app bars and the navigation drawer. The Navigation component also ensures a consistent and predictable user experience by adhering to an established set of principles.

What does navigate up mean?

The Up button is used to navigate within an app based on the hierarchical relationships between screens. For instance, if screen A displays a list of items, and selecting an item leads to screen B (which presents that item in more detail), then screen B should offer an Up button that returns to screen A.

Why the Behaviour of the back and up buttons must be different?

The problem is that up and back have different behavior. If a user is at the start destination, the Up button should not be shown. When your app is launched using a deep link on another app's task, Up should take users to the hierarchical parent destination and not back to the other app.