使用Swift实现将照片保存到iOS系统相册App同名自定义文件夹

• 首先在项目的Info.plist中添加相册权限声明：
  • 保存图片必备：NSPhotoLibraryAddUsageDescription，值填写你希望向用户展示的权限申请说明，比如“需要相册权限保存图片到本地”
  • 若需要兼容iOS 14以下版本的相册读取校验，额外添加NSPhotoLibraryUsageDescription，值同上述说明
• 引入系统相册依赖框架：import Photos

核心逻辑分为4步：1. 获取App名称 2. 校验相册访问权限 3. 查找/创建App同名相册文件夹 4. 保存图片到指定文件夹

完整代码示例 #

import Photos

class PhotoAlbumManager: NSObject {
    static let shared = PhotoAlbumManager()
    
    // 获取App名称
    private var appName: String {
        Bundle.main.infoDictionary?["CFBundleDisplayName"] as? String ?? 
        Bundle.main.infoDictionary?["CFBundleName"] as? String ?? "DefaultAppName"
    }
    
    // 获取App对应的自定义相册，不存在则创建
    private func getAppAlbum() -> PHAssetCollection? {
        // 先查找已存在的同名相册
        let fetchOptions = PHFetchOptions()
        fetchOptions.predicate = NSPredicate(format: "title = %@", appName)
        let collections = PHAssetCollection.fetchAssetCollections(with: .album, subtype: .albumRegular, options: fetchOptions)
        
        if let album = collections.firstObject {
            return album
        }
        
        // 不存在则创建新相册
        var albumId: String?
        do {
            try PHPhotoLibrary.shared().performChangesAndWait {
                albumId = PHAssetCollectionChangeRequest.creationRequestForAssetCollection(withTitle: self.appName).placeholderForCreatedAssetCollection.localIdentifier
            }
            guard let id = albumId else { return nil }
            return PHAssetCollection.fetchAssetCollections(withLocalIdentifiers: [id], options: nil).firstObject
        } catch {
            print("创建相册失败：\(error.localizedDescription)")
            return nil
        }
    }
    
    // 对外暴露的保存图片方法
    func saveImageToAppAlbum(image: UIImage, completion: @escaping (Bool, Error?) -> Void) {
        // 先校验相册权限
        PHPhotoLibrary.requestAuthorization(for: .readWrite) { status in
            guard status == .authorized || status == .limited else {
                completion(false, NSError(domain: "PhotoAlbumError", code: -1, userInfo: [NSLocalizedDescriptionKey: "未获得相册访问权限"]))
                return
            }
            
            guard let album = self.getAppAlbum() else {
                completion(false, NSError(domain: "PhotoAlbumError", code: -2, userInfo: [NSLocalizedDescriptionKey: "获取/创建相册失败"]))
                return
            }
            
            // 保存图片到指定相册
            PHPhotoLibrary.shared().performChanges {
                let assetRequest = PHAssetChangeRequest.creationRequestForAsset(from: image)
                guard let placeholder = assetRequest.placeholderForCreatedAsset else { return }
                let albumChangeRequest = PHAssetCollectionChangeRequest(for: album)
                albumChangeRequest?.addAssets([placeholder] as NSFastEnumeration)
            } completionHandler: { success, error in
                DispatchQueue.main.async {
                    completion(success, error)
                }
            }
        }
    }
}

调用示例 #

// 假设你已经拿到要保存的UIImage对象
guard let targetImage = UIImage(named: "test_image") else { return }
PhotoAlbumManager.shared.saveImageToAppAlbum(image: targetImage) { success, error in
    if success {
        print("图片保存成功")
    } else {
        print("保存失败：\(error?.localizedDescription ?? "未知错误")")
    }
}

• 所有相册操作的回调默认在子线程执行，涉及UI更新的逻辑需要手动切回主线程
• iOS 14新增的有限相册权限下，上述代码可正常执行，用户仅能看到你保存到相册的内容
• 如果需要保存网络图片，需要先将网络图片下载转为UIImage对象后再调用上述保存方法

内容的提问来源于stack exchange，提问作者Anam Shafique