Make default Facebook UIActivity work with new sharing method of FBSDKShareKit (tested on v4.7.1)

UIActivity+CCAFacebookAppActivity.h

//
//  UIActivity+CCAFacebookAppActivity.h
//  CCAFacebookAppActivity
//
//  Created by Jean-Luc Dagon on 28/02/15.
//  Copyright (c) 2015 Cocoapps. All rights reserved.
//
//  MIT License
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.
//

#import <UIKit/UIKit.h>
#import <FBSDKShareKit/FBSDKShareKit.h>

@interface UIActivity (CCAFacebookAppActivity)<FBSDKSharingDelegate>

@end

UIActivity+CCAFacebookAppActivity.m

//
//  UIActivity+CCAFacebookAppActivity.m
//  CCAFacebookAppActivity
//
//  Created by Jean-Luc Dagon on 28/02/15.
//  Copyright (c) 2015 Cocoapps. All rights reserved.
//
//  MIT License
//
//  Permission is hereby granted, free of charge, to any person obtaining a copy
//  of this software and associated documentation files (the "Software"), to deal
//  in the Software without restriction, including without limitation the rights
//  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the Software is
//  furnished to do so, subject to the following conditions:
//
//  The above copyright notice and this permission notice shall be included in
//  all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
//  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
//  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
//  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
//  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
//  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
//  THE SOFTWARE.
//

#import "UIActivity+CCAFacebookAppActivity.h"
#import <objc/runtime.h>
#import <FBSDKCoreKit/FBSDKCoreKit.h>
#import <FBSDKShareKit/FBSDKShareKit.h>

const void *CCAFacebookAppActivityDialogParamsKey;

@implementation UIActivity (CCAFacebookAppActivity)

//////////////////////////////////////////////////////////////////////////////////////////

+ (void)load
{
    // Swizzling done as described on NSHipster
    // http://nshipster.com/method-swizzling/
    
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        
        Class klass = NSClassFromString([NSString stringWithFormat:@"UISoc%@", @"ialActivity"]);
        CCASwizzleInstanceMethod(klass,
                                 @selector(prepareWithActivityItems:),
                                 @selector(cca_prepareWithActivityItems:));
        CCASwizzleInstanceMethod(klass,
                                 @selector(canPerformWithActivityItems:),
                                 @selector(cca_canPerformWithActivityItems:));
        CCASwizzleInstanceMethod(klass,
                                 @selector(performActivity),
                                 @selector(cca_performActivity));
        
        
    });
}

+ (NSString *)cca_defaultFacebookActivityType
{
    static NSString *_activityType = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _activityType = [@[@"com", @"apple", @"UIKit", @"activity", @"PostToFacebook"]
                         componentsJoinedByString:@"."];
    });
    return _activityType;
}

+ (BOOL)cca_canUseFacebookAppForSharing
{
    FBSDKShareDialog *dialog = [[FBSDKShareDialog alloc] init];
    dialog.mode = FBSDKShareDialogModeNative;
    return [dialog canShow];
}

- (BOOL)cca_canUseFacebookActivityOverride
{
    return ([[self activityType] isEqualToString:[self.class cca_defaultFacebookActivityType]]
            && [self.class cca_canUseFacebookAppForSharing]);
}

- (BOOL)cca_canPerformWithActivityItems:(NSArray *)activityItems
{
    if ([self cca_canUseFacebookActivityOverride]) {
        return YES;
    }
    return [self cca_canPerformWithActivityItems:activityItems];
}

- (void)cca_prepareWithActivityItems:(NSArray *)activityItems
{
    if (![self cca_canUseFacebookActivityOverride]) {
        [self cca_prepareWithActivityItems:activityItems];
        return;
    }
    
    BOOL containsImage = NO;
    BOOL containsURL = NO;
    
    NSURL *sharedURL = nil;
    NSString *sharedText = nil;
    NSMutableArray *sharedImages = [NSMutableArray array];
    
    for (id itemSource in activityItems) {
        id item = nil;
        if ([itemSource conformsToProtocol:@protocol(UIActivityItemSource)]) {
            item = [(id<UIActivityItemSource>)itemSource activityViewController:(UIActivityViewController *)self.activityViewController itemForActivityType:[self activityType]];
        } else {
            item = itemSource;
        }
        
        if ([item isKindOfClass:[NSURL class]]) {
            sharedURL = (NSURL *)item;
            containsURL = YES;
        } else if ([item isKindOfClass:[NSString class]]) {
            sharedText = (NSString *)item;
        } else if ([item isKindOfClass:[UIImage class]]) {
            FBSDKSharePhoto *photo = [[FBSDKSharePhoto alloc] init];
            photo.image = item;
            photo.userGenerated = NO;
            [sharedImages addObject:photo];
            containsImage = YES;
        }
        
    }
    
    if (!containsURL && !containsImage) {
        [self activityDidFinish:NO];
        return;
    }
    if (containsURL && containsImage) {
        if (sharedText) {
            sharedText = [sharedText stringByAppendingFormat:@" %@", [sharedURL absoluteString]];
        } else {
            sharedText = [sharedURL absoluteString];
        }
    }
    
    if (containsImage) {
        FBSDKSharePhotoContent *photoParams = [[FBSDKSharePhotoContent alloc] init];
        photoParams.photos = [sharedImages copy];
        
        objc_setAssociatedObject(self, &CCAFacebookAppActivityDialogParamsKey, photoParams, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
        
    } else {
        FBSDKShareLinkContent *linkParams = [[FBSDKShareLinkContent alloc] init];
        linkParams.contentURL = sharedURL;
        linkParams.contentTitle = sharedText;
        objc_setAssociatedObject(self, &CCAFacebookAppActivityDialogParamsKey, linkParams, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    }
}

- (void)cca_performActivity
{
    if (![self cca_canUseFacebookActivityOverride]) {
        [self cca_performActivity];
        return;
    }
    
    id params = objc_getAssociatedObject(self, &CCAFacebookAppActivityDialogParamsKey);
    if (!params) {
        [self activityDidFinish:NO];
        return;
    }
    
    [FBSDKShareDialog showFromViewController:self.activityViewController withContent:params delegate:self];
    
}

static void CCASwizzleInstanceMethod(Class klass, SEL originalSelector, SEL swizzledSelector)
{
    Method originalMethod = class_getInstanceMethod(klass, originalSelector);
    Method swizzledMethod = class_getInstanceMethod(klass, swizzledSelector);
    
    BOOL didAddMethod =
    class_addMethod(klass,
                    originalSelector,
                    method_getImplementation(swizzledMethod),
                    method_getTypeEncoding(swizzledMethod));
    
    if (didAddMethod) {
        class_replaceMethod(klass,
                            swizzledSelector,
                            method_getImplementation(originalMethod),
                            method_getTypeEncoding(originalMethod));
    } else {
        method_exchangeImplementations(originalMethod, swizzledMethod);
    }
}

#pragma mark -
- (void)sharer:(id<FBSDKSharing>)sharer didCompleteWithResults:(NSDictionary *)results {
    [self activityDidFinish:YES];
}

- (void)sharer:(id<FBSDKSharing>)sharer didFailWithError:(NSError *)error {
    [self activityDidFinish:NO];
}

- (void)sharerDidCancel:(id<FBSDKSharing>)sharer {
    [self activityDidFinish:NO];
}

@end