Hello, I am a UK-based Android professional and I can help you with this project.
I've been an Android developer since 2011, originally creating an app for an upcoming UK telecoms company. Since then, I've gone on to deliver excellent value and first-class service to clients all over the world.
I can make sure that this file upload feature is working for you, test extensively on a wide array of Android devices and versions, as well as making sure that you're completely satisfied with my work.
Feel free to PM me regarding this project.
Regards,
Michael