How to start developing a store app for a beginner android developer?

Question

Eclipse

Hello dear developers. I appeal to those who have experience in developing applications for android like a 220 volt store application. Tell me which way to go, I just started learning android and java. Interested in such things that it is easier and faster to do, which way to go.
As I understand it, data can be obtained from an existing store on cms in 2 ways: 1. This is through a yml file, each time updating the application when prices change (maybe this method is easier, I would like to hear it from you) 2. Synchronization method, as I understand it 2x bases, one sql base with the available goods on the server and attach the sqlite phone base to it.
The second question is whether there are ready-made separate parts of the code that would reduce the time for a novice developer: for example, registration, a barcode scanner, a shopping cart. Thank you for your understanding, if I put it somewhere incorrectly, I apologize, since my basic education is still economic

Answer 1

The database with the base of prices and goods is by no means sewn into the code, the application must be able to load it from the server. XML or some kind of database synchronization is up to you.
There are plenty of ready-made components for all occasions.