How to use Activity lifecycle in an Android app?

Understanding the Android Activity Lifecycle is crucial for developing efficient and responsive Android applications. The Activity Lifecycle defines the different states an Activity can go through and how to handle each state properly.

Here’s a simple overview of the important lifecycle methods you should know:

• onCreate(): Called when the activity is first created. This is where you initialize your activity, set up UI elements, and populate data.
• onStart(): Called when the activity is becoming visible to the user.
• onResume(): Called when the activity will start interacting with the user.
• onPause(): Called when the system is about to put the activity into the background.
• onStop(): Called when the activity is no longer visible to the user.
• onDestroy(): Called before the activity is destroyed.
• onRestart(): Called after the activity has been stopped, just prior to it being started again.

Here is an example of how to implement these lifecycle methods in your Activity:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Initial setup code
    }

    @Override
    protected void onStart() {
        super.onStart();
        // Activity is now visible
    }

    @Override
    protected void onResume() {
        super.onResume();
        // Activity is now interacting with the user
    }

    @Override
    protected void onPause() {
        super.onPause();
        // Activity is going to the background
    }

    @Override
    protected void onStop() {
        super.onStop();
        // Activity is no longer visible
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // Clean up resources
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        // Activity is restarting
    }
}