User account dictionary

Hi good people, i am developing an app off which i want users to create "user account and password". i am using dictionary feature in MIT2 app inventor for this approach it crashes the app.
any help

You are using global secondUserName as both a list and as a dictionary.

Which is it?

The easy way to store user name and password is to store them in a dictionary, username as key, and password as value.

thank you for this idea i use your method which have pre-define user account, however i want the users to create account on their own.

we need to know where you want to save your data? tinydb? tinywebdb?or mysql? clouddb?

and there are many tutorials for user register and login, have you tried to search one?

thanks for advise i want store them in tinydb

then retrieve the users from tinydb when screen1.initialize.

when new users register, add to users and save.

thank you for your time

i have try option to create user account where i want the app to notify the user if the enter user name created earlier.
when create new user account with a password i notification "new user account added". however if i try to verify the exitance of that user account by way of entering the same user name i don't get "user name already exist" . if try to login with that account it doesn't work where am i getting it wrong.

Why you are comparing a key and its value?

i want to verify if the key is already in the dictionary

then use is key in dictionary? block

i try that and if i create new user account the crash