Override UIActivityViewController to switch out to Facebook app (for Open Graph stories)

Question

There's two kinds of Facebook story: standard 'link' content, or richer Open Graph stories.

iOS provides UIActivityController , which lets you share 'link' content but doesn't let you perform Open Graph sharing. For that I use FBSDKShareKit , which accomplishes this by switching out to the Facebook app if it's installed).

I want best of both worlds, though: present a UIActivityController , and whenever Facebook is selected (see image), I want it to switch out to the Facebook app. Is this possible?

Answer 1

It is possible :) Just create a new class - lets say FacebookActivityItem:

// .h
@protocol FacebookActivityItemDelegate <NSObject>
- (void)facebookItemWasSelected;
@end

@interface FacebookActivityItem : NSObject<UIActivityItemSource>
@property (nonatomic, weak) id <FacebookActivityItemDelegate> delegate;
@end

// .m
@implementation FacebookActivityItem

/// called to determine data type. only the class of the return type is consulted. it should match what -itemForActivityType: returns later
- (id)activityViewControllerPlaceholderItem:(UIActivityViewController *)activityViewController {
    return UIActivityTypePostToFacebook;
}

/// called to fetch data after an activity is selected. you can return nil.
- (nullable id)activityViewController:(UIActivityViewController *)activityViewController itemForActivityType:(NSString *)activityType {

    if ([activityType isEqualToString:UIActivityTypePostToFacebook]) {

        if (self.delegate != nil) {
            [self.delegate facebookItemWasSelected];
        }
    }

    return nil;
}

@end

Now in your UIViewController, add an instance of this to the UIActivityViewController:

FacebookActivityItem *fbActivityItem = [FacebookActivityItem new];
fbActivityItem.delegate = self;

self.activityViewController = [[UIActivityViewController alloc] initWithActivityItems:@[fbActivityItem] applicationActivities:nil];

Now implement the method -facebookItemWasSelected in your UIViewController and tell it that it implements the FacebookActivityItemDelegate. In this method just dismiss the activityViewController and implement your custom form with the FacebookSDK!