Android Google Drive Integration assistance

Hello I am making google drive integration to my app For freelancing purpose, I have made sample app in which I have already integrated google drive api, user selects his google account and image file can be sent to drive (with function saveFileToDrive()) Now I want to send file without selecting accounting everytime. i.e. once he authorizes the account, for next time sending of file, app should not ask for selecting or authorizing his google account. App must be able to send file in background I have given sample project that described above