This is a complete tutorial, discussing how to build a simple calculator app for Android. Check it out, and implement some of the recommended improvements.

In this tutorial we go through the steps needed to build your first Android app. You will create a simple UI, add some Java code, and then run your app.

Assuming you’re running Android Studio with the editor window for the example app (W2A.java) open, your first step is to set a breakpoint on the public void onCreate(Bundle savedInstanceState) line.