I bought 3 baby puffer fish and they don&#39;t seem to be eating pellets, flakes or bloodworms.
Apk is the android package. R.java (auto generated file) when compiled along with .class (java classes) generated .dex file but these files are not deployable. .dex files are then reprocessed along with manifest file, and other resources (mp3, video, image) and .apk file is generated. This file is deployable.
An APK is the Android equivalent to an .exe program on your computer. Instead of downloading an app from the Play Store, you simply install it yourself without the Play Store's help (see our guide on installing apps outside of Google Play.