What is an Activity in Android and what is it used for?

Activity is a fundamental building block of an Android application, representing a single screen with a user interface.

Main functions and purpose:

• User Interface: Displays visual elements (Layout) and interacts with the user.
• Lifecycle: Managed by the Android system and has a set of states (creation, start, pause, stop, destroy).
• Navigation: Allows transitioning between different screens of the application.
• Event Handling: Responds to user actions and system events.

Example of creating a simple Activity:

class MainActivity : AppCompatActivity() {  
    override fun onCreate(savedInstanceState: Bundle?) {  
        super.onCreate(savedInstanceState)  
        setContentView(R.layout.activity_main) // Binding to layout  
    }  
}