Autocomplete Forms in Android?

Question

Android

There was an idea to create (as a good practice) an application that would store pairs of login-password-site_address, and automatically fill out an authorization form when entering a certain site.
The following questions arose during the design

• How does the Android OS identify the necessary forms for autofill? (That is, how the system knows that this field should contain a login, and the other should contain a login)
  
• How to store a database with security-critical authentication information?
  

Answer 1

1. Not android determines, but the browser itself. He remembers simply, namely, there is a certain dictionary of fields. For example, for login it is: email, login, user, username. And if there are several of them on one page, then priority is given and the most important one is selected.
2. Store the database in encrypted form (it is best to come up with your own encryption algorithm), and when you ask for a password, then decode it.