SwiftUI中Firebase Firestore无法保存数据问题求助

现象 #

代码实现 #

模型定义 #

struct Box: Identifiable, Hashable, Codable {
    @DocumentID var id: String?
    var boxName: String
    var boxSize: String

    enum CodingKeys: String, CodingKey {
        case id
        case boxName
        case boxSize
    }

    var dictionary: [String: Any] {
        let data = (try? JSONEncoder().encode(self)) ?? Data()
        return (try? JSONSerialization.jsonObject(with: data, options: .mutableContainers) as? [String: Any]) ?? [:]
    }
}

ViewModel实现 #

class BoxViewModel: ObservableObject {
    @Published var box: Box
    private var db = Firestore.firestore()

    init(box: Box = CashBox(boxName: "", boxSize: "")) {
        self.box = box
    }

    private func addNewBox(_ box: Box){
        print("the name  \(box.boxName)")
        let _ = db.collection("Box")
            .addDocument(data: box.dictionary)
    }

    func addBox() {
        self.addNewBox(box)
    }
    
    func setBoxData(boxName: String, boxSize: String){
        self.box.boxName = boxName
        self.box.boxSize = boxSize
    }
}

视图代码 #

struct CashBoxView: View {
    @State var boxName = ""
    @State var boxSize = ""
    @EnvironmentObject var boxViewModel: BoxViewModel

    var body: some View {
        Text("Enter box name")
        TextField("", text: $boxName)

        Text("Enter box size")
        TextField("", text: $boxSize)

        Button(action: {
            boxViewModel.setBoxData(boxName: boxName, boxSize: boxSize)
            boxViewModel.addBox()
        }) {
            Text("Done")
        }
    }
}

排查方向 #

从你的描述看，box.boxName能正常打印，说明对象数据没问题，以下是几个核心排查点：

1. EnvironmentObject注入验证
   确认父视图已通过.environmentObject(BoxViewModel())完成ViewModel注入。如果未注入，@EnvironmentObject会直接触发崩溃，但既然能打印数据，大概率已注入，可再检查注入逻辑是否覆盖当前视图层级。

2. Firestore权限规则
   默认Firestore规则仅允许认证用户读写数据，如果当前未做用户登录，数据会被拦截。可临时修改规则测试（测试后务必改回安全规则）：

   rules_version = '2';
   service cloud.firestore {
     match /databases/{database}/documents {
       match /{document=**} {
         allow read, write: if true;
       }
     }
   }
   

3. 字典转换逻辑问题
   当前通过JSONEncoder转Data再转字典的方式存在不确定性，比如@DocumentID标记的可选id可能编码异常。建议手动构建字典替代：

   var dictionary: [String: Any] {
       var dict: [String: Any] = [
           "boxName": boxName,
           "boxSize": boxSize
       ]
       if let id = id {
           dict["id"] = id
       }
       return dict
   }
   

4. 错误捕获缺失
   当前addDocument未处理错误，添加回调获取具体失败原因：

   db.collection("Box").addDocument(data: box.dictionary) { error in
       if let error = error {
           print("保存失败原因: \(error.localizedDescription)")
       } else {
           print("数据保存成功")
       }
   }
   

5. ViewModel初始化笔误
   初始化代码中写的是CashBox(boxName: "", boxSize: "")，但你的模型是Box，这里是明显笔误，需改为Box(boxName: "", boxSize: "")，避免初始化异常。

内容的提问来源于stack exchange，提问作者Rahaf