I'm writing an app for a retailer, but my client wants that once that the user has logged in the app does not let him/her log out.
My question is: Is this a permitted behavior on Apple apps? Will it get rejected? I've been looking up for a policy related to this, but haven't found anythin that either allows or denies this.
Thanks in advance.
You cannot prevent the user from just killing the app. But she does not necessarily be logged out. If you mark her as "logged in" by means of some persistant store (such as user preferences), you can have him be logged in automatically next time she starts the app.
This is a design that I have seen in many apps. I do not think that it would get you rejected. The user would have to delete the app completely to log out.
One possibility: put a "change login" option into the preferences. At least on iPhone, that is very far away from the app, at the bottom of the settings app which most users never find. Even then you could only let the user be logged out completely once she is logged in with a different valid login.
My recommendation: don't take the control away from the user. Explain to your client that there is a balance between marketing necessities and the danger of annoying important customers who might unduly amplify negative sentiments. Accomodate the needs of your client by making it a bit tedious to log out - but not more.