Android APP desing for existing code

I'm looking for a skilled Android developer to create a utility tool APP. The tool will primarily utilize existing code, so the ability to integrate pre-existing codebases.

Key Features:
Just need a new apk with great design and new technology for our existing code. may need to add couple functions

Ideal Skills:
- Proficient in Android development
- Experience with GPS functionalities
- Able to work with and modify existing code.