Retrieve multiple data from firebase to my android applciation : I am building an application that needs to retrieve a multiple data from my firebase database and store the data in my application. 

> This is my Database Structure, and I want to retrieve all data from 1 upto the last number as well as retrieve the data inside each number.

[Click me to view image][1]


  [1]: https://i.stack.imgur.com/2YMRG.png

Does anyone have any idea how to this? Thanks in advance.