【swift3.0】【自定义相册】【Photos.framework】

-IOS8.0+后，苹果开始推荐使用Photos.framework来自定义相册

-PhotosKit的框架类的解释

// 1.1 列出所有系统的智能相册
let smartAlbumsFetchResult = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .albumRegular, options: nil)

// 1.3取出所有用户创建的相册
let topLevelUserCollections = PHCollectionList.fetchTopLevelUserCollections(with: nil)

// 懒加载模型数组:相簿列表数据
fileprivate lazy var albums : [AlbumItem] = [AlbumItem]()

// 获取相册列表
fileprivate func getAlbumLists(_ collection : PHFetchResult<PHAssetCollection>) {
for index in 0..<collection.count {
// 获取当前相簿内的照片
let resultOptions = PHFetchOptions()
resultOptions.sortDescriptors = [NSSortDescriptor(key: "creationDate", ascending: true)]
// 只获取图片资源（排除音视频资源）
resultOptions.predicate = NSPredicate(format: "mediaType = %d", PHAssetMediaType.image.rawValue)
let assetCollection = collection[index]
let assetFetchResult = PHAsset.fetchAssets(in: assetCollection, options: resultOptions)

// 没有图片的空相簿不显示
if assetFetchResult.count > 0 {
let items = AlbumItem(title: assetCollection.localizedTitle!, fetchResult: assetFetchResult as! PHFetchResult<AnyObject>)
let resource = getFirstImageAtPHFetchResult(assetFetchReult: assetFetchResult)
items.firstImage = resource.firstImage
items.info = resource.info
albums.append(items)             }
}
}

// 遍历assetFetchReult结果集，可以得到每一个单独照片
let cacheImageManager = PHCachingImageManager()
let asset = assetFetchReult.firstObject!
cacheImageManager.stopCachingImagesForAllAssets()
cacheImageManager.requestImage(for: asset, targetSize: targetSize, contentMode: .aspectFill, options: nil) { (image : UIImage?, info : [AnyHashable : Any]?) in
}