Android Single Page Utility App

Hi, I have coded a utility app that will post gps location + other android specifications to server. I am facing some scheduler and issues for keeping service alive always, let me know if you can help me in this? Project Details: 1. Click on app icon -> A page will be displayed, i will show you design it has only single activity with one EditText in it (inventory #) 2. User will enter that number and activity either closed by saving (Inventory number) in preferences for future use or activity will be moved to background. 3. and from there service will keep posting data to server (android specifications + gps) to api I can provide parameter details + api function name with you. Technical Specifications: 1. Api Level Support Required : from version 15+ to 28 2. Please dont rely on alaram manager only but upto specific api level where required, and for latest api levels latest techniques. 3. battery must not drain (so code efficiently) 4. i need source code after project is complete. If you wish to work in my existing code, option is there depending on solution (if you want to write your own code upto you). lowest bidder wins My Budget: $50-$70 Thank you!