Hi ,
I have read your description , and can do it easily .
I CAN WORK IN LESS BUDGET ALSO . WE CAN DISCUSS BUDGET IN CHAT .
As you described :-
1] I have experience in android app development , I have developed many android apps .
2] You want to to give digital books and competitive study material and videos from the app to the students of different grads :- For this I will create an android app , in which students can download the study material , and you can upload any book and video .
3] For different grades , i will put option in app from which student can choose their grade .
Let me know if you have any other requirements .
My Android App with web service (sending GET and POST requests to server and response to user ) is published on play store , i can show you that app also .
I use JSON Parsing for this type of apps .
And I will make your app with high quality , i will also use Material Design for designing of your app as i have experience in it also .
Please Contact me and tell me more about your project .I can start working right now .