Hey,
I am new to freelancing that's why charging less and the number of days to complete would be 7 days, i mentioned 20 days as i'll be available to you if you would want changes. About me, I work as an android developer in an Netherlands based company. I have good experience in writing complex networking apps with their back-end and I usually work at night. I invite you to share more details about the project.
Cheers,
Tushar