Should back button close the app or go deeper in it?

1. What is the proper way to close an app?
2. How do I close an app from the back button?
3. What does the back button do on Android?

What is the proper way to close an app?

Close one app: Swipe up from the bottom, hold, then let go. Swipe up on the app. Close all apps: Swipe up from the bottom, hold, then let go. Swipe from left to right.

How do I close an app from the back button?

Many apps require the user to press the 'Back' button two times within an interval to successfully close the application, which is considered the best practice.

What does the back button do on Android?

The Back button appears in the system navigation bar at the bottom of the screen and is used to navigate in reverse-chronological order through the history of screens the user has recently worked with.