在iOS 8上破坏了AssetsLibrary框架

Question

我在iOS 8上遇到了一个关于资源库框架的问题，这似乎是iOS 8中的一个错误。如果我创建了一个名为'MyMedia‘的相册，然后将其删除，那么当我尝试再次创建该相册时，下面的这段代码会返回'nil’，表明相册'MyMedia‘并不存在，尽管它并不存在，因为我使用了'Photos’应用程序删除了它。

__block ALAssetsGroup *myGroup = nil;
__block BOOL addAssetDone = false;
NSString *albumName = @"MyMedia";
[assetsLib addAssetsGroupAlbumWithName:albumName
                           resultBlock:^(ALAssetsGroup *group) {
                               myGroup = group;
                               addAssetDone = true;
                           } failureBlock:^(NSError *error) {
                               NSLog( @"failed to create album: %@", albumName);
                               addAssetDone = true;
                           }];

while (!addAssetDone) {
    [[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:0.05f]];
}
return myGroup; // returns nil if group has previously been created and then deleted

当创建一个全新的专辑‘MyMedia2’时，同样的方法也适用。是否有其他人遇到过此问题，并知道解决方法或解决方案？是迁移到新的'Photos‘框架的唯一解决方案，还是我做了一些不正确的事情？请注意，此代码始终在iOS7.X上运行

实际上，重现此问题的步骤如下-> 1.卸载您的拍照应用程序并将其保存到自定义相册2.在iOS照片下删除其中保存了照片的自定义相册3.安装您的应用程序4.如果您使用该应用程序拍照或录制视频，它不会创建或存储它们。如果你在iOS相册下查看，你会发现定制相册并不存在，也不存在使用该应用程序拍摄的照片/视频。

Answer 1

我之前的回答是错误的。我还没有真正测试过它。我最终弄清楚了什么是必须要做的，这很困难，但我让它起作用了。为了让我的应用程序在iOS 7.x.X和iOS 8.X.x上运行，并创建一个之前被应用程序删除的自定义相册，我必须这样做-->

1. 我写了两段代码:一段在iOS 8.x.x上使用照片框架，另一段在iOS 7.x.x
2. Sp上使用AssetsLibrary框架应用程序可以在两个iOS版本上运行，我将应用程序链接到照片框架，然后将其从必需更改为可选，这样它就不会在iOS 7.x.x
3. 上加载，因为照片框架代码不能在iOS 7.x.x上运行时直接调用，所以我必须更改它，以便它加载类、函数(和块！)在运行时动态

下面是在iPhone上运行的代码块。这应该也能在模拟器中工作-->

// PHPhotoLibrary_class will only be non-nil on iOS 8.x.x
Class PHPhotoLibrary_class = NSClassFromString(@"PHPhotoLibrary");

if (PHPhotoLibrary_class) {

   /**
    *
    iOS 8..x. . code that has to be called dynamically at runtime and will not link on iOS 7.x.x ...

    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:title];
    } completionHandler:^(BOOL success, NSError *error) {
        if (!success) {
            NSLog(@"Error creating album: %@", error);
        }
    }];
    */

    // dynamic runtime code for code chunk listed above            
    id sharedPhotoLibrary = [PHPhotoLibrary_class performSelector:NSSelectorFromString(@"sharedPhotoLibrary")];

    SEL performChanges = NSSelectorFromString(@"performChanges:completionHandler:");

    NSMethodSignature *methodSig = [sharedPhotoLibrary methodSignatureForSelector:performChanges];

    NSInvocation* inv = [NSInvocation invocationWithMethodSignature:methodSig];
    [inv setTarget:sharedPhotoLibrary];
    [inv setSelector:performChanges];

    void(^firstBlock)() = ^void() {
        Class PHAssetCollectionChangeRequest_class = NSClassFromString(@"PHAssetCollectionChangeRequest");
        SEL creationRequestForAssetCollectionWithTitle = NSSelectorFromString(@"creationRequestForAssetCollectionWithTitle:");
        [PHAssetCollectionChangeRequest_class performSelector:creationRequestForAssetCollectionWithTitle withObject:albumName];

    };

    void (^secondBlock)(BOOL success, NSError *error) = ^void(BOOL success, NSError *error) {
       if (success) {
           [assetsLib enumerateGroupsWithTypes:ALAssetsGroupAlbum usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
               if (group) {
                   NSString *name = [group valueForProperty:ALAssetsGroupPropertyName];
                   if ([albumName isEqualToString:name]) {
                       groupFound = true;
                       handler(group, nil);
                   }
               }
           } failureBlock:^(NSError *error) {
               handler(nil, error);
           }];
       }

       if (error) {
           NSLog(@"Error creating album: %@", error);
           handler(nil, error);
       }
   };

   // Set the success and failure blocks.
   [inv setArgument:&firstBlock atIndex:2];
   [inv setArgument:&secondBlock atIndex:3];

   [inv invoke];

}
else {   
   // code that always creates an album on iOS 7.x.x but fails
   // in certain situations such as if album has been deleted
   // previously on iOS 8...x. .              
   [assetsLib addAssetsGroupAlbumWithName:albumName
       resultBlock:^(ALAssetsGroup *group) {
       handler(group, nil);
   } failureBlock:^(NSError *error) {
       NSLog( @"Failed to create album: %@", albumName);
       handler(nil, error);
   }];
}

Answer 2

使用Adam的回答和Marin Todorov在ALAssetsLibrary，ALAssetsLibrary+CustomPhotoAlbum上的分类来创建相册，并将照片放入其中，下面的代码替换了该分类中的主要workHorse，它可以在iOS7设备和iOS 8.1设备上运行，对于那些需要同时拥有两者的人来说。

它给出了两个关于未知类上的performSelector的警告，任何改进都是值得感谢的：

(它不会复制您没有创建的共享相册中的照片，并且会失败并显示消息，任何增强功能也是很好的)

1)添加“照片”框架，设置为“可选”

2)包括导入行#import < Photos/PHPhotoLibrary.h >

    //----------------------------------------------------------------------------------------
- (void)addAssetURL:(NSURL *)assetURL
            toAlbum:(NSString *)albumName
         completion:(ALAssetsLibraryWriteImageCompletionBlock)completion
            failure:(ALAssetsLibraryAccessFailureBlock)failure
{
NSLog();
    __block BOOL albumWasFound = NO;

    //-----------------------------------------
    ALAssetsLibraryGroupsEnumerationResultsBlock enumerationBlock;
    enumerationBlock = ^(ALAssetsGroup *group, BOOL *stop)
    {
NSLog(@"  ALAssetsLibraryGroupsEnumerationResultsBlock");
        // Compare the names of the albums
        if ([albumName compare:[group valueForProperty:ALAssetsGroupPropertyName]] == NSOrderedSame)
        {
NSLog(@"--------------Target album is found");
            // Target album is found
            albumWasFound = YES;

            // Get a hold of the photo's asset instance
            // If the user denies access to the application, or if no application is allowed to
            //   access the data, the failure block is called.
            ALAssetsLibraryAssetForURLResultBlock assetForURLResultBlock =
            [self _assetForURLResultBlockWithGroup:group
                                          assetURL:assetURL
                                        completion:completion
                                           failure:failure];

            [self assetForURL:assetURL
                resultBlock:assetForURLResultBlock
               failureBlock:failure];

            // Album was found, bail out of the method
            *stop = YES;
        }

        if (group == nil && albumWasFound == NO)
        {
NSLog(@"--------------Target album does not exist");
            // Photo albums are over, target album does not exist, thus create it

            // Since you use the assets library inside the block,
            //   ARC will complain on compile time that there’s a retain cycle.
            //   When you have this – you just make a weak copy of your object.
            ALAssetsLibrary * __weak weakSelf = self;

            // If iOS version is lower than 5.0, throw a warning message
            if (! [self respondsToSelector:@selector(addAssetsGroupAlbumWithName:resultBlock:failureBlock:)])
            {
NSLog(@"--------------Target album does not exist and does not respond to addAssetsGroupAlbumWithName");
            } else {
NSLog(@"--------------Target album does not exist addAssetsGroupAlbumWithName");

                // -----------   PHPhotoLibrary_class will only be non-nil on iOS 8.x.x  -----------
                Class PHPhotoLibrary_class = NSClassFromString(@"PHPhotoLibrary");
NSLog(@"PHPhotoLibrary_class %@ ", PHPhotoLibrary_class);

                if (PHPhotoLibrary_class)
                {
NSLog(@"iOS8");

                    // ---------  dynamic runtime code  -----------
                    id sharedPhotoLibrary = [PHPhotoLibrary_class performSelector:NSSelectorFromString(@"sharedPhotoLibrary")];
NSLog(@"sharedPhotoLibrary %@ ", sharedPhotoLibrary);

                    SEL performChanges = NSSelectorFromString(@"performChanges:completionHandler:");

                    NSMethodSignature *methodSig = [sharedPhotoLibrary methodSignatureForSelector:performChanges];

                    NSInvocation* inv = [NSInvocation invocationWithMethodSignature:methodSig];
                    [inv setTarget:sharedPhotoLibrary];
                    [inv setSelector:performChanges];

                    void(^firstBlock)() = ^void()
                    {
NSLog(@"firstBlock");
                        Class PHAssetCollectionChangeRequest_class = NSClassFromString(@"PHAssetCollectionChangeRequest");
                        SEL creationRequestForAssetCollectionWithTitle = NSSelectorFromString(@"creationRequestForAssetCollectionWithTitle:");
NSLog(@"PHAssetCollectionChangeRequest_class %@ ", PHAssetCollectionChangeRequest_class);


                        [PHAssetCollectionChangeRequest_class performSelector:creationRequestForAssetCollectionWithTitle withObject:albumName];

                    };

                    void (^secondBlock)(BOOL success, NSError *error) = ^void(BOOL success, NSError *error)
                    {
NSLog(@"secondBlock");
                       if (success)
                       {
NSLog(@"success");
                            [self enumerateGroupsWithTypes:ALAssetsGroupAlbum usingBlock:^(ALAssetsGroup *group, BOOL *fullStop)
                            {
                               if (group)
                               {
NSLog(@"group %@ ", group);
                                   NSString *name = [group valueForProperty:ALAssetsGroupPropertyName];
                                   if ([albumName isEqualToString:name])
                                   {
NSLog(@"[albumName isEqualToString:name] %@ ", name);
                                        ALAssetsLibraryAssetForURLResultBlock assetForURLResultBlock =
                                        [self _assetForURLResultBlockWithGroup:group
                                                                      assetURL:assetURL
                                                                    completion:completion
                                                                       failure:failure];

                                        [self assetForURL:assetURL
                                            resultBlock:assetForURLResultBlock
                                           failureBlock:failure];

                                        *fullStop = YES;
                                   }
                               }
                            } failureBlock:failure];
                       }

                       if (error)
                       {
NSLog(@"Error creating album: %@", error);
                       }
                   };

                   // Set the success and failure blocks.
                   [inv setArgument:&firstBlock atIndex:2];
                   [inv setArgument:&secondBlock atIndex:3];

                   [inv invoke];

                } else {
NSLog(@"iOS7");
                    [self addAssetsGroupAlbumWithName:albumName resultBlock:^(ALAssetsGroup *createdGroup)
                    {
                        // Get the photo's instance, add the photo to the newly created album
                        ALAssetsLibraryAssetForURLResultBlock assetForURLResultBlock =
                            [weakSelf _assetForURLResultBlockWithGroup:createdGroup
                                                            assetURL:assetURL
                                                          completion:completion
                                                             failure:failure];

                        [weakSelf assetForURL:assetURL
                                  resultBlock:assetForURLResultBlock
                                 failureBlock:failure];
                    }
                    failureBlock:failure];
                }
            }
            // Should be the last iteration anyway, but just in case
            *stop = YES;
        }
    };



    // Search all photo albums in the library
    [self enumerateGroupsWithTypes:ALAssetsGroupAlbum
                  usingBlock:enumerationBlock
                failureBlock:failure];
}

Answer 3

您可以尝试我下面的方法在iOS 7和iOS 8上创建相册

#define PHOTO_ALBUM_NAME @"AlbumName Videos"
#pragma mark - Create Album
-(void)createAlbum{

// PHPhotoLibrary_class will only be non-nil on iOS 8.x.x
Class PHPhotoLibrary_class = NSClassFromString(@"PHPhotoLibrary");

if (PHPhotoLibrary_class) {


    // iOS 8..x. . code that has to be called dynamically at runtime and will not link on iOS 7.x.x ...

    [[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
        [PHAssetCollectionChangeRequest creationRequestForAssetCollectionWithTitle:PHOTO_ALBUM_NAME];
    } completionHandler:^(BOOL success, NSError *error) {
        if (!success) {
            NSLog(@"Error creating album: %@", error);
        }else{
            NSLog(@"Created");
        }
    }];
}else{
    [self.library addAssetsGroupAlbumWithName:PHOTO_ALBUM_NAME resultBlock:^(ALAssetsGroup *group) {
        NSLog(@"adding album:'Compressed Videos', success: %s", group.editable ? "YES" : "NO");

        if (group.editable == NO) {
        }

    } failureBlock:^(NSError *error) {
        NSLog(@"error adding album");
    }];
}}