iOS 自定义相册/获取系统相册相簿图片

项目Demo下载 记得 star哦
先来了解几个类的作用
导入头文件#import <Photos/Photos.h>
PHAsset : 一个资源, 比如一张图片\一段视频
PHAssetCollection : 一个相簿
PHImageManager 图片管理者,是单例,发送请求才能从asset获取图片
PHImageRequestOptions图片请求选项

思路. 通过 API 获取相簿, 再通过相簿获取对应的媒体资源PHAsset,通过资源获取图片

为什么要通过PHAsset 再获取图片. 因为直接给的话. 图片多/大,以及图片的显示十分消耗内存,并且容易导致内存暴涨,页面滑动卡顿等问题.

所以我们要先获取资源对象PHAsset的集合. 再根据需求(图片大小, 是否原图等)通过PHAsset获取图片.获取非常简单,有对应的 API

获取相簿

//获取相簿的所有原图  全局队列
        let queue = DispatchQueue.global()
        queue.async {
//            typedef NS_ENUM(NSInteger, PHAssetCollectionType) {
//                PHAssetCollectionTypeAlbum      = 1,///这是里对应的 PHAssetCollectionSubtype 用户自定义的相册文件也在其subtype
//                PHAssetCollectionTypeSmartAlbum = 2,///对应的为系统里的相册文件 下面的200- 211等都为其subtype
//                PHAssetCollectionTypeMoment     = 3,
//            } NS_ENUM_AVAILABLE_IOS(8_0);
//            typedef NS_ENUM(NSInteger, PHAssetCollectionSubtype) {
//
//                // PHAssetCollectionTypeAlbum regular subtypes
//                PHAssetCollectionSubtypeAlbumRegular         = 2,///
//                PHAssetCollectionSubtypeAlbumSyncedEvent     = 3,
//                PHAssetCollectionSubtypeAlbumSyncedFaces     = 4,面孔
//                PHAssetCollectionSubtypeAlbumSyncedAlbum     = 5,
//                PHAssetCollectionSubtypeAlbumImported        = 6,
//
//                // PHAssetCollectionTypeAlbum shared subtypes
//                PHAssetCollectionSubtypeAlbumMyPhotoStream   = 100,///
//                PHAssetCollectionSubtypeAlbumCloudShared     = 101,///
//
//                // PHAssetCollectionTypeSmartAlbum subtypes         collection.localizedTitle
//                PHAssetCollectionSubtypeSmartAlbumGeneric    = 200,///
//                PHAssetCollectionSubtypeSmartAlbumPanoramas  = 201,///全景照片
//                PHAssetCollectionSubtypeSmartAlbumVideos     = 202,///视频
//                PHAssetCollectionSubtypeSmartAlbumFavorites  = 203,///个人收藏
//                PHAssetCollectionSubtypeSmartAlbumTimelapses = 204,///延时摄影
//                PHAssetCollectionSubtypeSmartAlbumAllHidden  = 205,/// 已隐藏
//                PHAssetCollectionSubtypeSmartAlbumRecentlyAdded = 206,///最近添加
//                PHAssetCollectionSubtypeSmartAlbumBursts     = 207,///连拍快照
//                PHAssetCollectionSubtypeSmartAlbumSlomoVideos = 208,///慢动作
//                PHAssetCollectionSubtypeSmartAlbumUserLibrary = 209,///所有照片
//                PHAssetCollectionSubtypeSmartAlbumSelfPortraits NS_AVAILABLE_IOS(9_0) = 210,///自拍
//                PHAssetCollectionSubtypeSmartAlbumScreenshots NS_AVAILABLE_IOS(9_0) = 211,///屏幕快照
//                                                               = 1000000201///最近删除知道值为（1000000201）但没找到对应的TypedefName
//                // Used for fetching, if you don't care about the exact subtype
//                PHAssetCollectionSubtypeAny = NSIntegerMax /所有类型
//            } NS_ENUM_AVAILABLE_IOS(8_0);

            //获取所有的自定义相簿
            let assetCollections = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .albumRegular, options: nil)
            print("获取到的相簿    \(assetCollections)")
            assetCollections.enumerateObjects {[weak self] collection, index, stop in
                print("123213")
                self?.enumerateAssetInAssetCollection(assetCollection: collection, original: false)
            }
            //获得相机胶卷
            let cameraRoll = PHAssetCollection.fetchAssetCollections(with: .smartAlbum, subtype: .smartAlbumUserLibrary, options: nil).lastObject
            if let roll = cameraRoll {
                self.enumerateAssetInAssetCollection(assetCollection: roll, original: false)
            }   
        }

遍历获取图片

//遍历相册中的图片
    func enumerateAssetInAssetCollection(assetCollection: PHAssetCollection,original: Bool) {
        print("相册的名字\(assetCollection.localizedTitle)")
        
        //获取某个相簿中的所有 PHAsset 对象
        let assets = PHAsset.fetchAssets(in: assetCollection, options: nil)
        let options = PHImageRequestOptions()
        //调整模式。当size为PHImageManagerMaximumSize时不适用。默认为PHImageRequestOptionsResizeModeFast
        options.resizeMode = .fast
        ////只返回一个结果，阻塞直到可用(或失败)。默认为不
        options.isSynchronous = true
        //交付模式。默认为PHImageRequestOptionsDeliveryModeOpportunistic
        options.deliveryMode = .fastFormat
    
        assets.enumerateObjects { [weak self] asset, index, stop in
            let size = original ? CGSize.init(width: asset.pixelWidth, height: asset.pixelHeight) : .zero
            PHImageManager.default().requestImage(for: asset, targetSize: size, contentMode: PHImageContentMode.default, options: options) { image, info in
                guard let _self = self else {
                    return
                }
                if let img = image {
                    _self.listData.append(img)
                }

            }
        }
        DispatchQueue.main.async {
            self.collectionView.reloadData()
        }

    }