Facebook iOS SDK , exception against FBSession, *** Assertion failure in -[FBSession close]

Question

I'm using facebook sdk 3.0.8 for ios. when i try to login with facebook it works fine but sometimes when i try to login after logging out then app is being crashed. here is exception message ``` *** Assertion failure in -[FBSession close], /Users/jacl/src/ship/ios-sdk/src/FBSession.m:342 ``` can you please tell me where i'm going wrong? Here is code inside AppDelegate ``` - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation { // attempt to extract a token from the url return [FBSession.activeSession handleOpenURL:url]; } - (void)applicationWillTerminate:(UIApplication *)application { [self.session close]; } #pragma mark Template generated code // FBSample logic // It is possible for the user to switch back to your application, from the native Facebook application, // when the user is part-way through a login; You can check for the FBSessionStateCreatedOpenening // state in applicationDidBecomeAc…

Accepted Answer

Looking at FBSession.m, the assertion in `close` is as follows:

```
NSAssert(self.affinitizedThread == [NSThread currentThread], @"FBSession: should only be used from a single thread");
```

Are you calling `-close` from a thread other than the one you created the session on?

Looking into this further. You're misusing the API. You are creating

```
appDelegate.session = [[FBSession alloc] init]; 
```

but then you are calling

```
[FBSession openActiveSessionWithPermissions ...
```

which creates an entirely new session. Meaning you never opened `appDelegate.session`, and therefore you should not try to close it. What you should be doing instead is the following:

```
[FBSession openActiveSessionWithPermissions ...
appDelegate.session = [FBSession activeSession];
```

Another option is to just do:

```
appDelegate.session = [[FBSession alloc] init];
[appDelegate.session openWithCompletionHandler: ...
```

Facebook iOS SDK , exception against FBSession, *** Assertion failure in -[FBSession close]

Solution

Problem