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仅获取包含至少一张照片的PHAssetCollections

photokit swift ios

7

Phlippie Bosman · 技术社区 · 7 年前

在iOS PhotoKit中,我可以获取所有非空相册,如下所示:

let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "estimatedAssetCount > 0")
let albumFetchResult = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .any, options: albumFetchOptions)

albumFetchResult.enumerateObjects({ (collection, _, _) in
    // Do something with the album...
})

let fetchOptions = PHFetchOptions()
fetchOptions.predicate = NSPredicate(format: "mediaType = %d", PHAssetResourceType.photo.rawValue)
let fetchResults = PHAsset.fetchAssets(in: collection, options: fetchOptions)

1 回复 | 直到 7 年前

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Phlippie Bosman 7 年前

如果不同时获取集合中的项目,则无法像这样过滤集合。看见 the docs

实现这一点的方法是获取用户创建的所有相册,然后使用仅返回图像的谓词从相册中获取资产。

因此,将其编码为:

var userCollections: PHFetchResult<PHAssetCollection>!
// Fetching all PHAssetCollections with at least some media in it
let options = PHFetchOptions()
    options.predicate = NSPredicate(format: "estimatedAssetCount > 0")
// Performing the fetch
userCollections = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .albumRegular, options: options)

// Getting the specific collection (I assumed to use a tableView)
let collection = userCollections[indexPath.row]
let optionsToFilterImage = PHFetchOptions()
    optionsToFilterImage.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.Image.rawValue)
// Fetching the asset with the predicate to filter just images
let justImages = PHAsset.fetchAssets(in: collection, options: optionsToFilterImage)

if justImages.count > 0 {
    // Display it
} else {
    // The album has no images
}