like this,
so,i have to do that the when user reinstall app and after login his old username that he used to enter first time should automaticallly aded to his account.
please help
I don’t think this is possible, because you can’t get the Device ID and storing such information online is a bad idea in terms of Data Security/Privacy.
use firebase. once user logged in, save his name as tag and user name as value. so next time or every time user try to login, first check whether the number is the database or not. if not allow the app to send OTP, if not automatically call the tag value and display… simple…
You can use tinydb (for local) and file (for backup).
Tinydb to get data if app is installed. But if the user clear data or uninstall application, we have backup data on the files stored in the storage, as long as the files are in the storage, we can get back data again.
I didn’t understand what data you want to recover exactly.
What you want to save is the username?
If yes, just link the phone number to the username. If user type number +5521999874569 you just have to check in your online database what is the username related to that cellphone number.
This is not exactly the same that you said that you want, but solve the problem.