Check if logged in on ios facebook sdk 3.0

Question

I am using iOS facebook SDK 3.0. How can i check if the user is already logged in?

I tried the line below but it does not work properly. It sometimes returns NO although I am logged in. Any suggestions?

if (FBSession.activeSession.isOpen == YES)
{
  // post to wall else login
}

-- EDIT --

this is how I open my Facebook session:

NSArray *permissions = [[NSArray alloc] initWithObjects:
                        @"user_likes", 
                        @"read_stream",
                        @"publish_actions",
                        nil];
return [FBSession openActiveSessionWithPermissions:permissions
                                      allowLoginUI:allowLoginUI
                                 completionHandler:^(FBSession *session,
                                                     FBSessionState state,
                                                     NSError *error) {
                                     [self sessionStateChanged:session
                                                         state:state
                                                         error:error];
                                 }];

The first time it needs login and so it works. If i try this while I am already logged in the FBSession.activeSession.isOpen returns NO.

Answer 1

You can check if you have a valid token by trying to open a new session without allowing the login UI

if (FBSession.activeSession.isOpen)
{
    // post to wall
} else {
    // try to open session with existing valid token
    NSArray *permissions = [[NSArray alloc] initWithObjects:
                            @"user_likes", 
                            @"read_stream",
                            @"publish_actions",
                            nil];
    FBSession *session = [[FBSession alloc] initWithPermissions:permissions];
    [FBSession setActiveSession:session];
    if([FBSession openActiveSessionWithAllowLoginUI:NO]) {
        // post to wall
    } else {
        // you need to log the user
    }
}