I just finished a tutorial on how to develop an android application that retrieves updated posts from a Blog using JSON data.
The link to the JSON data used to retrieve the posts, was the blog name ending with "/api/get_recent_summary"
How can I find the link of the JSON data for different websites?
For example the website for The Time Magazine http://time.com
The quickest and easiest way is to use google developer tools in Google Chrome.
1st go to google developer tools.
2nd Click on the "Network" tab.
3rd click on the XHR sub-tab. XHR(XMLHttpRequest)
if a site uses json it will be listed under the XHR sub-tab. You can search through the different return objects by using the preview sub-sub-tab.
Here is a link to a website step by step how to on finding the json files http://www.gregreda.com/2015/02/15/web-scraping-finding-the-api/
Although the above way is the easiest it is not the most stable way of getting the info you need. Many sites make changes to the return data without any notice. This will probably break your app...
I think what you are looking for is an API(Application programming interface). Most web APIs return json or xml. You should start by searching for the api documentation for the specific site that you want to get json data from. Example documentation for sites that have public api feeds are github api or youtub api. Many of these will require authentication in order to get the desired json response but the documentation should show you how to do it.
Using a legitimate web api is the most stable way to go. Meaning your app has less chance of randomly breaking all of the time due to feed changes, url changes... I hope this helps!