How can I use Facebook instance in a ViewController? - ios5

Question

I'm having troubles developing an iOS 5 App with Facebook SDK integration.
My App has many ViewsController and for each of them I want to get different data from Facebook using different requests (of course).
At the moment I can get data only on the AppDelegate (following the official tutorial) but I need to get data in the view controller.
I tried 2 option:
1) Instantiate different Facebook instances on each ViewController
-It dosent' work, I don't know why but it seems that
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation;
is never called
2 Instantiate the Facebook instance in the AppDelegate and then use that instance in ViewControllers
- It don't works because with this code (found here: How do I persist a Facebook instance in multiple IOS view classes?)
- (void)viewDidLoad
{
[super viewDidLoad];
AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
Facebook *facebook = [appDelegate facebook];
}
facebook is nil.
Which is the proper way to work?

Answer 1

(I will edit my answer if you give me after that more feedback.)
I haven't used a lot the Facebook SDK but I remember having that problem when I tried.
The - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation implementation should be in your app delegate
If you need to access your Facebook instance in just one viewController (let's say MyFacebooViewController)
You can have something like this
#import <UIKit/UIKit.h>
#import "FBConnect.h"
#interface MyFacebookViewController : UIViewController <FBSessonDelegate, FBRequestDelegate>
#property (nonatomic, strong) Facebook *facebook;
...
#end
And your .m file should contain this
#import "MyFacebookViewController.h"
#import "MyAppDelegate.h"
#implementation MyFacebookViewController
#synthesize facebook = _facebook;
-(Facebook *)facebook
{
if(!_facebook){
_facebook = [[Facebook alloc] initWithAppId:MY_APP_ID andDelegate:self];
}
return _facebook;
}
-(void)viewDidLoad
{
[super viewDidLoad];
((MyAppDelegate *)([[UIApplication sharedApplication] delegate])).facebookViewController = self;
...
}
And of course you need to implement your FBSessionDelegate and FBRequestDelegate methods
In the AppDelegate :
#import <UIKit/UIKit.h>
#import "MyFacebookViewController.h"
#interface MyAppDelegate : UIResponder <UIApplicationDelegate>
...
#property (strong, nonatomic) MyFacebookConnectViewController *facebookViewController;
#end
And it's in the implementation file that you need to put the - (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
#implementation MyAppDelegate
#synthesize facebookViewController = _facebookViewController;
...
- (BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
return [self.facebookViewController.facebook handleOpenURL:url];
}
If you still have problems let me know!

Answer 2

I'm not editing my answer as this is code I've never tested.
If you want to use the same Facebook instance in different viewController this is one way to do it:
As already mentioned in your question, you should initialize it in the appDelegate (I would use a property.)
MyAppDelegate.h :
#import <UIKit/UIKit.h>
#import "FBConnect.h"
#interface MyAppDelegate : UIResponder <UIApplicationDelegate>
...
#property (strong, nonatomic) Facebook *facebook;
#end
MyAppDelegate.m :
#import "MyAppDelegate.h"
#implementation MyAppDelegate
#synthesize facebook = _facebook;
-(Facebook *)facebook
{
if(!_facebook){
_facebook = [Facebook alloc] initWithAppId:MY_APP_ID andDelegate:self];
}
return _facebook;
}
-(BOOL)application:(UIApplication *)application openURL:(NSURL *)url sourceApplication:(NSString *)sourceApplication annotation:(id)annotation
{
return [self.facebook handleOpenURL:url];
}
Then in any ViewController that you would want you could have a Facebook property that you would not alloc/init but you would ask it from the appDelegate this way
AnyViewController.h :
#import "MyAppDelegate.h"
#interface AnyViewController : UIViewController
...
#property (strong, nonatomic) Facebook *facebook;
#end
AnyViewController.m :
#import "AnyViewController.h"
#implementation AnyViewController
#synthesize facebook = _facebook;
-(Facebook *)facebook
{
if(!_facebook){
MyAppDelegate *theAppDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
_facebook = theAppDelegate.facebook;
}
return _facebook;
}
And of course the different ViewControllers you'll be using should implement the different SDK protocols depending on your needs
You should have a look at the sample project by Facebook that's called Hackbook