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.

Fleeceware apps on Google Play were found to abuse the Play Store policies and grossly charge users hundreds of dollars for mundance services like calculators and QR code scanners.

iOS/Android/Desktop: Default calculator apps suck. They work like a traditional handheld calculator, which only displays one value at a time and can only do basic math. If you want to do anything ...