Blankj/AndroidUtilCode ? reverse-engineered prompt

Build me an Android utility library that collects the most common helpers app developers need, so I can stop rewriting the same code over and over.

I want it to cover everyday stuff like logs, cache, files, permissions, networking, encryption, regex, threads, toast messages, snackbar style feedback, and other small Android helpers that make development faster. Please organize it as a reusable library with a main set of common utilities and a smaller set of extra utilities that are less often needed but still useful. It should be easy to drop into an Android project and use from Java.

If you need to, look up the current Android docs online so the code stays compatible and practical. Also include a simple demo or sample usage, plus tests where it makes sense, so it feels like a real polished utility package and not just a pile of helper classes.