I want to lock my application with a password which the user has set in the applications settings.
Each time the main acitivity of my app is going to be shown, a password dialog should be shown instead. I know how to do that, but i wonder… :
How do I store the password the user has set? I can’t store it in SharedPreferences because you can delete SharedPreferences in your phone’s settings. I thought about a textfile which holds the password, but this file can be deleted, cant it?
Any ideas?
One option is to put the password in the same file as where you have the other information (I reckon you want to protect the settings/data of the user). Just do not start the app when that file is missing or corrupted. What you have accomplished then, is that the information is rendered unusable if someone tampers with the data. Sign / encrypt your data file(s).
Another solution could be to store the password (hash!) on a webserver.