This tutorial is base on creating a very simple calculator for Android using Android Studio and it also assumes that you have Android Studio (2.3.2 was used) installed, know a little bit about java and ability to read and understand texts.

The application is really going to be simple and lazy in terms of programming, but it is enough to get you started.

The Application Rules
It can only use one operator
You must click on the equals (=) to get your result
Steps
The first thing you will need to do is to create an android project with Activity “MainActivity” and Layout “activity_main.xml.”

After this, you will need to design your layout with Buttons and a textview for displaying the results. Make sure it looks like the XML below with the appropriate onClick functions for easy communication with the MainActivity.

The source code doesn't display well here . Check here http://thetechlicense.com/2017/05/25/building-simple-calculator-android-studio/.


Now it is time to code our MainActivity as follow:

Create the onClick funtions
Seven variables
And create a view for the TextView
The code below will explain itself
MainActivity.java
The source code doesn't display well here . Check here http://thetechlicense.com/2017/05/25/building-simple-calculator-android-studio/.

Results after a successfully compilation
A very effective android application for calculating only integer values as shown below



Assignment
If you have compiled yours, you would notice the absence of the multiplication. You job is to fit that into the project. Very simple.

A complete Calculator is coming soon. Download apk here https://drive.google.com/open?id=0B0CkX8jlUfu2TWQ2QkRWLXJWdms.