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user30115770
Asked: 2025-04-16 10:55:58 +0800 CST

如何将照片选择器中的图像保存到 SwiftData

  • 772

我在将图像保存到 SwiftData 时遇到问题，并且我不完全确定最好的方法。

我有一个用于单个条目的 EntryModel 数据模型，如下所示：

@Model
class EntryModel {
   var type: EntryType
   var who: UserModel
   var what: String
   var value: Double? = nil
   var note: String
   @Attribute(.externalStorage) var images: [Data]?
   var when: Date = Date.now

  init(type: EntryType, who: UserModel, what: String, note: String, images: [Data] = [], when: Date) {
    self.type = type
    self.who = who
    self.what = what
    self.note = note
    self.images = images
    self.when = when
}

然后我创建了一个 NewEntryView，它允许用户创建一个新条目，并附加一些可选的图片来提供额外的信息。代码如下：

struct New EntryView {
   @State private var entryItems = [PhotosPickerItem]()
   @State private var entryImages = [Image]()

// Other code pertaining to different parts of my form

HStack {
    PhotosPicker(selection: $entryItems, maxSelectionCount: 5, matching: .images) {
        Image(systemName: "plus")
          .font(.title)
          .foregroundStyle(.adaptiveBlack)
          .frame(width: 80, height: 70)
          .background(
              RoundedRectangle(cornerRadius: 10)
                 .stroke(lineWidth: 2)
                 .fill(selectedEntryType.color)
                 .frame(width: 70, height: 60)
           )
       }
                        
       ScrollView(.horizontal) {
          HStack(spacing: 10) {
             ForEach(0..<entryImages.count, id: \.self) { i in
                entryImages[i]
                    .resizable()
                    .scaledToFill()
                    .clipShape(RoundedRectangle(cornerRadius: 10))
                    .frame(height: 60)
             }
          }
          .onChange(of: entryItems) {
             Task {
                entryImages.removeAll()
                                    
                for item in entryItems {
                   if let image = try? await item.loadTransferable(type: Image.self) {
                   entryImages.append(image)
                }
            }
        }
   }

// More code

Button {
   let entry = EntryModel(type: selectedEntryType, who: selectedUser!, what: titleTextField, note: noteTextField, when: selectedDate)
   modelContext.insert(entry)
} label: {
// Custom label
}

现在，通过当前的实现，我确实可以从我的相册中选择图像并将它们填充到 HStack 中。

当单击底部的按钮时，用户填写的其他信息也会保存到 SwiftData 中，并可在整个应用程序中使用。

我遇到的问题是将这些图像保存到 SwiftData 中以供整个应用程序使用。

我是否应该像其他值一样将它们插入到模型上下文中？如果是，该怎么做？

如果不是，那么我该如何更改我当前的代码？

任何帮助都将不胜感激。

顺便说一句，我不确定它是否相关，但自从我实现了 PhotosPicker 后，我在 Xcode 中收到以下警告：

PHPickerViewControllerDelegate_Private 不响应 _pickerDidPerformConfirmationAction：

swiftui

1 个回答

  1. Best Answer

    正如我在之前回答您的问题时所展示的那样，使用另一个模型来存储图像数据，并与 EntryModel 建立关系。

    这是一个完整工作的示例代码：

    
@main
struct TestApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
        .modelContainer(for: EntryModel.self)
    }
}

@Model class UserModel {
    var name: String
    var age: Int
    
    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }
}

@Model class ImageData {
    @Attribute(.externalStorage)
    var data: Data
    var entry: EntryModel?

    init(data: Data) {
        self.data = data
    }
}

@Model class EntryModel {
    var type: String
    var who: UserModel
    var what: String
    var value: Double? = nil
    var note: String
    var when: Date = Date.now

    @Relationship(deleteRule: .cascade, inverse: \ImageData.entry) var images: [ImageData]?

    init(type: String, who: UserModel, what: String, value: Double? = nil, note: String, images: [ImageData]? = nil, when: Date) {
        self.type = type
        self.who = who
        self.what = what
        self.value = value
        self.note = note
        self.images = images
        self.when = when
    }
}

struct ContentView: View {
    @Environment(\.modelContext) private var modelContext  // <--- here
    
    @State private var entryItems = [PhotosPickerItem]()
    @State private var entryImages = [Image]()
    
    @State private var imagesData = [ImageData]()  // <--- here
    
    var body: some View {
        VStack {
            Text("Select images first").font(.title)
            PhotosPicker(selection: $entryItems, maxSelectionCount: 5, matching: .images) {
                Image(systemName: "plus")
                    .font(.title)
                    .foregroundStyle(.secondary)
                    .frame(width: 80, height: 70)
                
                ScrollView(.horizontal) {
                    HStack(spacing: 10) {
                        ForEach(0..<entryImages.count, id: \.self) { i in
                            entryImages[i]
                                .resizable()
                                .scaledToFit()
                                .clipShape(RoundedRectangle(cornerRadius: 10))
                                .frame(height: 60)
                        }
                    }
                    .onChange(of: entryItems) {
                        // --- here
                        Task { @MainActor in
                            entryImages.removeAll()
                            for item in entryItems {
                                if let imageData = try? await item.loadTransferable(type: Data.self) {
                                    imagesData.append(ImageData(data: imageData))
                                    if let uiImage = UIImage(data: imageData) { entryImages.append(Image(uiImage: uiImage))
                                    }
                                }
                            }
                        }
                    }
                }
            }
            
            // example code
            Button("Save Images to SwiftData") {
                let entryModel = EntryModel(type: "type",
                                            who: UserModel(name: "test-user", age: 32),
                                            what: "what",
                                            note: "note",
                                            images: imagesData, // <--- here
                                            when: Date())
                modelContext.insert(entryModel)  // <--- here
            }.buttonStyle(.bordered)
            
            Text("Images from SwiftData")
            ImagesView()
        }
    }
}

// example code to display the saved images
struct ImagesView: View {
    @Environment(\.modelContext) private var modelContext
    @Query private var entries: [EntryModel]
    
    var body: some View {
        ForEach(entries) { entry in
            ScrollView (.horizontal) {
                HStack {
                    if let imagesData = entry.images {
                        ForEach(imagesData) { imgData in
                            if let uimg = UIImage(data: imgData.data) {
                                Image(uiImage: uimg).resizable()
                                    .frame(width: 123, height: 123)
                            }
                        }
                    }
                }
            }
        }.padding()
    }
}
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