faceookConnect.m

// in appDelegate.m
- (BOOL)application:(UIApplication *)application
            openURL:(NSURL *)url
  sourceApplication:(NSString *)sourceApplication
         annotation:(id)annotation {
    
    BOOL wasHandled = [FBAppCall handleOpenURL:url sourceApplication:sourceApplication];
    
    // add app-specific handling code here
    return wasHandled;
    //return [self.session handleOpenURL:url];
}



// connect function
- (void)facebookConnect {

    // Initialize a session object
    FBSession *session = [[FBSession alloc] init];
    // Set the active session
    [FBSession setActiveSession:session];
    // Open the session
    [FBSession openActiveSessionWithReadPermissions:@[@"basic_info"] allowLoginUI:YES completionHandler:^(FBSession *session, FBSessionState status, NSError *error) {
        
        // Respond to session state changes,
        // ex: updating the view
        if(status == FBSessionStateClosed){
            NSLog(@"user click disconnect.");
            return;
        }
        if(status == FBSessionStateClosedLoginFailed){
            NSLog(@"user does not want login.");
            return;
        }else{
            NSLog(@"response status: %d", status);
        }
        
        NSString *accessToken = nil;
        
        // update from facebook api 3.2
        if(session.accessTokenData)
        accessToken = session.accessTokenData.accessToken;
        
        if(accessToken){
            AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
            NSDictionary *parameters = @{@"fb_token":accessToken};
            [manager POST:@"https://banck.tw/api/fb_token" parameters:parameters success:^(AFHTTPRequestOperation *operation, id JSON) {
                // your server returns, save data to userDefaults
            } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
                // your server fails
            }];
        }
    }];
}

// disconnect
- (void)disconnectFacebook {
    [FBSession.activeSession closeAndClearTokenInformation];
}