My Facebook app crash while the authenticate screen dismissed - objective-c

Question

I am trying to integrate facebook iOS SDK in my app, in my app delegate header I do the following :
#import <UIKit/UIKit.h>
#import "Facebook.h"
#import "FBConnect.h"
#class ViewController;
#interface AppDelegate : UIResponder <UIApplicationDelegate>
{
Facebook *facebook;
}
#property (nonatomic,strong) Facebook *facebook;
#property (strong, nonatomic) UIWindow *window;
#property (strong, nonatomic) ViewController *viewController;
#end
and in implementation file's method didFinishLaunchingWithOptions method:
MyFacebooDelegate *controllerDelegate = [[MyFacebooDelegate alloc] init];
facebook = [[Facebook alloc] initWithAppId:appID andDelegate:controllerDelegate];
NSUserDefaults *userDefault = [NSUserDefaults standardUserDefaults];
if([userDefault objectForKey:#"FBAccessTokenKey"] && [userDefault objectForKey:#"FBExpirationDateKey"])
{
facebook.accessToken = [userDefault objectForKey:#"FBAccessTokenKey"];
facebook.expirationDate = [userDefault objectForKey:#"FBExpirationDateKey"];
}
if(![facebook isSessionValid])
{
NSArray *permision = [[NSArray alloc]initWithObjects:#"read_stream",nil] ;
[facebook authorize:permision];
}
where the MyFacebooDelegate class is where I implement the Facebook delegates like the FBSessionDelegate and others.
Also I handled the handleOpenURL and the OpenURL too, when I run the app i get the facebook authenticate screen in safari and then press "Okay" the screen dismissed and back to my app, but some times the app crash and exit and here is where the compiler tells me the error :
- (void)fbDialogLogin:(NSString *)token expirationDate:(NSDate *)expirationDate {
self.accessToken = token;
self.expirationDate = expirationDate;
[_lastAccessTokenUpdate release];
_lastAccessTokenUpdate = [[NSDate date] retain];
[self reloadFrictionlessRecipientCache];
if ([self.sessionDelegate respondsToSelector:#selector(fbDidLogin)]) {
[self.sessionDelegate fbDidLogin];
}
Specifically the compiler indicate this line :
if ([self.sessionDelegate respondsToSelector:#selector(fbDidLogin)]) {
any help will be appreciated

Answer 1

Mohammed
The following line is wrong:
if ([self.sessionDelegate respondsToSelector:#selector(fbDidLogin)]) {
It should look like this:
if ([self.sessionDelegate respondsToSelector:#selector(fbDidLogin:)]) {

Answer 2

When you instantiate your session delegate:
MyFacebooDelegate *controllerDelegate = [[MyFacebooDelegate alloc] init];
facebook = [[Facebook alloc] initWithAppId:appID andDelegate:controllerDelegate];
You do not retain it in any other way. If you look at the Facebook SDK file Facebook.h, you see that the sessionDelegate property is of type assign. Which means you must be responsible for making sure the delegate object exists when it's time to send messages to it.
To fix this, add your AppDelegate.h file:
#property (strong, nonatomic) MyFacebooDelegate *controllerDelegate;
And in didFinishLaunchingWithOptions:, instead of the code at the top of my post, do:
self.controllerDelegate = [[MyFacebooDelegate alloc] init];
facebook = [[Facebook alloc] initWithAppId:appID andDelegate:self.controllerDelegate];
This way, a strong reference will be maintained to your delegate object and it will not be prematurely deallocated.
Hope this helps! Let me know if you have any questions.