如何通过iOS 16 Photos Picker(SwiftUI)获取图片路径并存储至JSON？

核心说明 #

iOS的Photos框架出于隐私保护，不会直接提供系统相册图片的绝对路径给App。正确的做法是：将选中的图片复制到App的沙箱目录（比如Documents或Caches），然后存储这个沙箱内的路径到JSON，后续通过该路径读取本地文件展示。

实现步骤 #

1. 配置Photos Picker并获取选中图片 #

使用PHPickerViewController选择图片，提取图片数据后保存到沙箱：

import PhotosUI
import SwiftUI

struct PhotoPickerView: UIViewControllerRepresentable {
    @Binding var selectedImagePath: String?
    
    func makeUIViewController(context: Context) -> PHPickerViewController {
        var configuration = PHPickerConfiguration()
        configuration.filter = .images
        configuration.selectionLimit = 1
        
        let picker = PHPickerViewController(configuration: configuration)
        picker.delegate = context.coordinator
        return picker
    }
    
    func updateUIViewController(_ uiViewController: PHPickerViewController, context: Context) {}
    
    func makeCoordinator() -> Coordinator {
        Coordinator(self)
    }
    
    class Coordinator: NSObject, PHPickerViewControllerDelegate {
        let parent: PhotoPickerView
        
        init(_ parent: PhotoPickerView) {
            self.parent = parent
        }
        
        func picker(_ picker: PHPickerViewController, didFinishPicking results: [PHPickerResult]) {
            picker.dismiss(animated: true)
            
            guard let result = results.first else { return }
            if result.itemProvider.canLoadObject(ofClass: UIImage.self) {
                result.itemProvider.loadObject(ofClass: UIImage.self) { [weak self] image, error in
                    guard let uiImage = image as? UIImage, error == nil else { return }
                    self?.saveImageToSandbox(uiImage)
                }
            }
        }
        
        private func saveImageToSandbox(_ image: UIImage) {
            guard let imageData = image.jpegData(compressionQuality: 0.8) else { return }
            
            // 获取Documents目录
            let documentsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
            // 生成唯一文件名避免重复
            let fileName = UUID().uuidString + ".jpeg"
            let fileURL = documentsDir.appendingPathComponent(fileName)
            
            do {
                try imageData.write(to: fileURL)
                // 存储相对路径（避免App重装后绝对路径变化）
                let relativePath = fileURL.path.replacingOccurrences(of: documentsDir.path, with: "")
                DispatchQueue.main.async {
                    self.parent.selectedImagePath = relativePath
                }
            } catch {
                print("保存图片失败：\(error.localizedDescription)")
            }
        }
    }
}

2. 将路径存入JSON文件 #

创建可编码的数据模型，将路径写入JSON：

struct ImageRecord: Codable {
    var imageRelativePath: String?
}

// 保存路径到JSON的方法
func savePathToJSON(path: String) {
    let record = ImageRecord(imageRelativePath: path)
    let encoder = JSONEncoder()
    encoder.outputFormatting = .prettyPrinted
    
    guard let jsonData = try? encoder.encode(record) else { return }
    
    let documentsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    let jsonURL = documentsDir.appendingPathComponent("imageRecords.json")
    
    do {
        try jsonData.write(to: jsonURL)
    } catch {
        print("写入JSON失败：\(error.localizedDescription)")
    }
}

3. 从JSON读取路径并展示图片 #

读取JSON中的相对路径，拼接成完整沙箱URL后加载图片：

// 读取JSON路径的方法
func loadPathFromJSON() -> String? {
    let documentsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    let jsonURL = documentsDir.appendingPathComponent("imageRecords.json")
    
    guard let jsonData = try? Data(contentsOf: jsonURL) else { return nil }
    let decoder = JSONDecoder()
    guard let record = try? decoder.decode(ImageRecord.self, from: jsonData) else { return nil }
    
    return record.imageRelativePath
}

// SwiftUI展示视图
struct ImageDisplayView: View {
    @State private var displayImage: UIImage?
    
    var body: some View {
        displayImage.map { Image(uiImage: $0) }
            .resizable()
            .scaledToFit()
            .onAppear {
                loadDisplayImage()
            }
    }
    
    private func loadDisplayImage() {
        guard let relativePath = loadPathFromJSON() else { return }
        let documentsDir = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
        let fileURL = documentsDir.appendingPathComponent(relativePath)
        
        if let imageData = try? Data(contentsOf: fileURL) {
            displayImage = UIImage(data: imageData)
        }
    }
}

关键注意事项 #

• 不要尝试存储系统相册的绝对路径：iOS沙箱限制App直接访问系统相册路径，且该路径不具备持久性，App重装或系统更新后会失效。
• 使用UUID命名文件：避免重复文件名导致图片被覆盖。
• 如需存储多张图片，可将ImageRecord修改为包含路径数组的模型，比如struct ImageRecords: Codable { var paths: [String] }。

内容的提问来源于stack exchange，提问作者Tyrel Smith