Getting "error validating access token" error using Facebook SDK

After a few days of having my own app run on my phone I start getting this error when requseting a friend list from Facebook: "error validating access token"

I'm using the Facebook SDK with the single signon turned off ( just开发者_高级运维 using the WebView login ).

When I logoff and then log back in - everything is fine again.

What does one do about this error and where does it come from?

It means that your token has expire. To avoid that problem you can ask for the permission "offline_access" so that you have a token that never expire.