PHFetchResult获取所有照片并按日期排序不一致

Question

PHFetchResult获取所有照片并按日期排序不一致

iosobjective-cphotosframeworkphphotolibraryphfetchoptions

7

我正在尝试构建一个简单的相片选择器，目前有两个选项：最近和收藏。我正在尝试通过creationDate获取所有照片，但是我的数据源返回的顺序不正确。开始的数据源中有几年前的照片，而散布在其中的照片则小于几分钟。我认为问题在于我需要首先告诉主要的fetchResult排序顺序，但我不认为这是可能的：Unsupported sort descriptor in fetch options: (creationDate, ascending, compare: 如有帮助，将不胜感激。代码：

@property (nonatomic, strong) NSMutableOrderedSet *recentsDataSource;
@property (nonatomic, strong) NSMutableOrderedSet *favoritesDataSource;

- (void)setup
{
    PHFetchResult *fetchResult = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum | PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAny options:nil];

    for (PHAssetCollection *sub in fetchResult)
    {
        PHFetchOptions *fetchOptions = [[PHFetchOptions alloc]init];

        fetchOptions.sortDescriptors = @[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:YES]];

        PHFetchResult *assetsInCollection = [PHAsset fetchAssetsInAssetCollection:sub options:fetchOptions];

        for (PHAsset *asset in assetsInCollection)
        {
            [self.recentsDataSource addObject:asset];

            if (asset.isFavorite)
            {
                [self.favoritesDataSource addObject:asset];
            }
        }
    }
}

- klcjr89

1个回答

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- klcjr89 · Accepted Answer

我自己想出了解决方法，以下是我的方案:

- (void)setup
{
    self.recentsDataSource = [[NSMutableOrderedSet alloc]init];
    self.favoritesDataSource = [[NSMutableOrderedSet alloc]init];

    PHFetchResult *assetCollection = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum | PHAssetCollectionTypeAlbum subtype:PHAssetCollectionSubtypeAny options:nil];

    PHFetchResult *favoriteCollection = [PHAssetCollection fetchAssetCollectionsWithType:PHAssetCollectionTypeSmartAlbum subtype:PHAssetCollectionSubtypeSmartAlbumFavorites options:nil];

    for (PHAssetCollection *sub in assetCollection)
    {
        PHFetchResult *assetsInCollection = [PHAsset fetchAssetsInAssetCollection:sub options:nil];

        for (PHAsset *asset in assetsInCollection)
        {
            [self.recentsDataSource addObject:asset];
        }
    }

    if (self.recentsDataSource.count > 0)
    {
        NSArray *array = [self.recentsDataSource sortedArrayUsingDescriptors:@[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]]];

        self.recentsDataSource = [[NSMutableOrderedSet alloc]initWithArray:array];
    }

    for (PHAssetCollection *sub in favoriteCollection)
    {
        PHFetchResult *assetsInCollection = [PHAsset fetchAssetsInAssetCollection:sub options:nil];

        for (PHAsset *asset in assetsInCollection)
        {
            [self.favoritesDataSource addObject:asset];
        }
    }

    if (self.favoritesDataSource.count > 0)
    {
        NSArray *array = [self.favoritesDataSource sortedArrayUsingDescriptors:@[[NSSortDescriptor sortDescriptorWithKey:@"creationDate" ascending:NO]]];

        self.favoritesDataSource = [[NSMutableOrderedSet alloc]initWithArray:array];
    }
}