Conclusion

Well done for setting up your first Activity! It’s a skill you’ll use over and over in your Android career. To recap, you learned:

• How to create a Compose app.
• What an Activity is.
• What the onCreate() lifecycle method does.

With a small amount of code, you created a functional chat app while learning some of the foundational elements of building an Android app. Although this Activity is small, Activities can get complicated as you add more Views. Later, you’ll learn how to separate the logic code out of your Activities. That will leave mostly only Jetpack Compose UI code in your Activities, keeping your code separated into logical components that are easier to understand, scale, and debug.

If you’d like to learn a bit about the old way of doing things in Android, see Android Documentation on Fragments.