how to check if already logged in Facebook in ios? - iphone

Question

I am using "Graph Api" For Facebook login with in my app. I successfully logIn and logged out with this code
facebook = [[Facebook alloc] initWithAppId:kAppId andDelegate:self.viewController];
and i using below code for already facebook logged in
if (![facebook isSessionValid]) {
[facebook authorize:permissions ];
}
My problem is i install Facebook App, and i logged in via Facebook App. then i run my app, it ask again login Facebook. how i solve this issue. it should take as a default FB app login credentials. i saw many app using this feature. anyone know the solution

Answer 1

1. In your AppDelegate.m file
define NSString *const FBSessionStateChangedNotification =
#"com.example:FBSessionStateChangedNotification";
replace com.example with your bundle identifier name
2.- In method
(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
[FBSession setActiveSession:[FBSession new]];
if ([FBSession activeSession].state == FBSessionStateCreatedTokenLoaded)
{
// means u are already logged in
//do ur code
[self openSessionWithAllowLoginUI:NO];
}
else
{ //do ur code
[self openSessionWithAllowLoginUI:YES];
}
}
3. whenenever and wherever this method is called after end of switch case write
- (void)sessionStateChanged:(FBSession *)session
state:(FBSessionState) state
error:(NSError *)error
{
[[NSNotificationCenter defaultCenter]
postNotificationName:FBSessionStateChangedNotification
object:session];
}
- (BOOL)openSessionWithAllowLoginUI:(BOOL)allowLoginUI
{
return [FBSession openActiveSessionWithReadPermissions:#"email"
allowLoginUI:allowLoginUI
completionHandler:^(FBSession *session, FBSessionState state, NSError *error)
{
[self sessionStateChanged:session state:state error:error];
}];
}
Sorry in your appDelegate.h file it should be
extern NSString *const FBSessionStateChangedNotification;