I am developing an application for Android/iOS that have a login and registration form.
Actually I am doing it using JSON to store an email and an encrypted password, and others user information in a MySql server. But I found a (Android Problem), How to send a email link to user recovery his password, I dont want to send his password directly to email, I´d like to send a unique link that he can call app again and submit a new password, I can't find a way to do it with MySql and stackmob shows me an easier way.
Problems:
I'm the Platform Evangelist for StackMob. I'll do my best to answer your questions.
StackMob does provide a Password Reset Feature. http://developer.stackmob.com/tutorials/android/Forgot-Password
Depends. If you want to add access controls to your data based on the currently logged in user, StackMob helps you do this. You can control create, read, update and delete permissions based on the user through relationships, roles and ownership (who created it).
No, you only have one StackMob app (and set of data) for all platforms iOS, Android, HTML5, etc. You use the same API keys for all versions of the app.
It's very easy to integrate Facebook login with StackMob so you user's can authenticate using Facebook. Once logged in you can access other data based on the user's permissions (see #2)