How to connect an android application with a website?

Question

Android

Can you suggest any site or article where it is written in detail how to link an android application to a site? How to work with the API in the application, send requests to the server and receive responses from the server?
The site is organized in such a way that it has many galleries with pictures. How to organize work with them in the application (viewing them, zooming in, etc.)?

Answer 1

1) the site must have an api that gives information
2) images must be given in different sizes, otherwise it will lag (this is very important, for the pager you first give small thumbnails, then if necessary, load in full size)
3) for requests I recommend retrofit
4) for asynchronous loading of picasso images