29 August 2011

My First Published App

Several days ago I release Ballistic Energy Calc on the Android Market. It's a free app that calculates muzzle energy and Taylor KO Factor. It isn't especially useful, but it is unique in the fact that it is the only ballistic energy calculator currently available for Android that includes the Taylor KO Factor. I developed and tested it on an Android 2.2 HTC Incredible. The GUI is pretty plain and fairly small, this should hopefully make the app available to users with a wide variety of hardware setups.

Bug: It appears that some users are able to type a space in an input field, despite my best efforts to limit the input using "android:inputType". This results in an IllegalStateException caused by a NumberFormatException. I will be sure to fix this in subsequent releases.

I learned a lot about android by doing this project and I encourge anybody reading this to try developing your own app. After developing the app and testing it for my own phone, I decided that I might as well publish it since somebody else might be looking for something like this. It's actually easy to become a publisher for Android. You just need to pay $25, upload your .apk, and fill out some fields such as the application name. The $25 is a one time fee, so you don't need to pay to publish additional apps. I hope to release some more apps in the future, hopefully of even greater use.


  1. I was looking for a velocity calculator, and yours was 1 of 2... yours was free, and the other was 99 cents. I got yours, of course, ha ha. But really, it's great, I only have 2 suggestions. 1) if you don't fill in all fields, the app crashes. I would either use a default value in fields that the user fails to define (and make sure the ABOUT section mentions this) or you could make a prompt that says one of the fields has no data, please retry. 2) I can't enter a decimal value in the grain field. I wanted to use this for recording air gun data, and pellets are often odd grain sizes (e.g., 10.9, 7.4, 5.2, etc.) Please let me know if you can add these features! Thanks so much, it's still a very nice app!

  2. Thank you for your interest in the app. Sorry for the delay, I've been busy with school and other activities. I just published an update to fix the blank field issue on December 24. I will also look into adding decimal value functionality in the next update.