This tutorial is all about accessing a MySQL database to retrieve some information and display it on an Android device.
Adding, changing or deleting records to or from a database is not covered in this tutorial.
There are several websites that teach you how to maintain a database.
The main reference in this case would certainly be W3Schools: PHP MySQL database
You can also find examples (code snippets) on my website via this link:PHP code snippets

Thank you for reading this tutorial.

In need of an assignment?
In this tutorial all the information is loaded into lists when the activity is created.
Can you change the code to have the item list loaded from the database when the subcategory selection (cbx2) changes? Which steps do you take to accomplish that?