“获取选项中不支持的谓词: osx中的标题==”测试“

Question

我目前正在开发一个应用程序，我需要在每个相册的手机上显示本地存储的图像。我已经成功地显示了所有的相册名称，现在当选择一个相册时，我想要显示这些图像。

func getLocalAlbums() {
    var albums: [AlbumModel] = [AlbumModel]()
    albumNamesDevice.removeAll()

    let options = PHFetchOptions()
    let topLvlOptions = PHFetchOptions()
    let userAlbums = PHAssetCollection.fetchAssetCollectionsWithType(.SmartAlbum, subtype: .SmartAlbumUserLibrary, options: options)
    let topLvlCollection = PHCollectionList.fetchTopLevelUserCollectionsWithOptions(topLvlOptions)

    let allAlbums = [topLvlCollection, userAlbums]

    for i in 0 ..< allAlbums.count {
        let result = allAlbums[i]

        result.enumerateObjectsUsingBlock { (asset, index, stop) in
            if asset is PHAssetCollection {
                let ass: PHAssetCollection = asset as! PHAssetCollection
                let fetchOptions = PHFetchOptions()

                fetchOptions.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.Image.rawValue)

                let newAlbum = AlbumModel(name: ass.localizedTitle!, count: ass.estimatedAssetCount, collection: ass)
                albums.append(newAlbum)
            }
        }
    }

    for item in albums {
        self.albumNamesDevice.append(item.name)
    }
}

func getAssetsFromAlbum(albumName: String) -> [PHAsset] {

    let options = PHFetchOptions()
    // Bug from Apple since 9.1, use workaround
    options.predicate = NSPredicate(format: "title = %@", albumName)
    options.sortDescriptors = [ NSSortDescriptor(key: "creationDate", ascending: true) ]

    let results = PHAsset.fetchAssetsWithMediaType(.Image, options: options)
    var assets = [PHAsset]()

    results.enumerateObjectsUsingBlock { (obj, index, stop) in

        if let asset = obj as? PHAsset {
            assets.append(asset)
        }
    }

    return assets
}

问题是下面一行：

options.predicate = NSPredicate(format: "title = %@", albumName)

我不断地发现错误：

由于“NSInvalidArgumentException”异常终止应用程序，原因：“获取选项中不支持谓词:标题==”“测试”

我在2014年就读到过，这是一个bug，但这怎么可能还没有被Apple devs解决呢？

有人知道这方面的工作吗？

Answer 1

最后，我找到了答案，或者至少找到了一个解决办法。

func getAssetsFromAlbum(albumName: String) -> [PHAsset] {

    let options = PHFetchOptions()
    // Bug from Apple since 9.1, use workaround
    //options.predicate = NSPredicate(format: "title = %@", albumName)
    options.sortDescriptors = [ NSSortDescriptor(key: "creationDate", ascending: true) ]

    let collection: PHFetchResult = PHAssetCollection.fetchAssetCollectionsWithType(.Album, subtype: .Any, options: nil)

    for k in 0 ..< collection.count {
        let obj:AnyObject! = collection.objectAtIndex(k)
        if obj.title == albumName {
            if let assCollection = obj as? PHAssetCollection {
                let results = PHAsset.fetchAssetsInAssetCollection(assCollection, options: options)
                var assets = [PHAsset]()

                results.enumerateObjectsUsingBlock { (obj, index, stop) in

                    if let asset = obj as? PHAsset {
                        assets.append(asset)
                    }
                }

                return assets
            }
        }
    }
    return [PHAsset]()
}