类初始化问题

Question

我认为这是一个简单的问题，但令人头疼。 当实际存在初始化程序时，我收到 ....has no initializers 错误。

这是我的代码：

（编辑：我已经更新了 PatientData 类以包含所有其他变量。我认为它们在解决问题方面没有什么不同，所以为了简洁起见，我将它们排除在外。）

数据结构

class PatientData: Identifiable, ObservableObject
{
    let id = UUID()
    
    @Published var patientName: String = "Name"
    @Published var patientAge: String = "Age"
    @Published var patientDOB: String = "DOB"
    @Published var patientPhone: String = "Phone"
    @Published var patientAddress: PatientAddress

    struct PatientAddress
    {
        var patientStreetAddress: String = "Street"
        var patientCity: String = "City"
        var patientState: String = "State"
        var patientZip: String = "Zip"
        
        init(patientStreetAddress: String, patientCity: String, patientState: String, patientZip: String)
        {
            self.patientStreetAddress = patientStreetAddress
            self.patientCity = patientCity
            self.patientState = patientState
            self.patientZip = patientZip
        }
    }
    
    @Published var facilityName: String = "Facility"
    @Published var facilityRoom: String = "Room Number"
    @Published var facilityFloor: String = "Floor"
    @Published var facilityPhoneNumber: String = "Phone Number"
    
    init(patientName: String, patientAge: String, patientDOB: String, patientPhone: String, patientAddress: PatientAddress, facilityName: String, facilityRoom: String, facilityFloor: String, facilityPhoneNumber: String)
    {
        self.patientName = patientName
        self.patientAge = patientAge
        self.patientDOB = patientDOB
        self.patientPhone = patientPhone
        self.patientAddress = patientAddress
        self.facilityName = facilityName
        self.facilityRoom = facilityRoom
        self.facilityFloor = facilityFloor
        self.facilityPhoneNumber = facilityPhoneNumber
    }
    init() {}
}

内容视图

struct ContentView: View
{
    @ObservedObject var patient = PatientData()
    ...
}

Answer 1

注意：

PatientData()

相当于：

PatientData.init()

这意味着如果您想以这种方式创建您的 PatientData：

@ObservedObject var patient = PatientData()

您需要提供一个匹配的 init 方法（它可以为空，因为您的所有 @Published 属性都已具有默认值）：

init() { }

---

编辑

查看您的完整代码，您的某个属性似乎没有初始值：

@Published var patientAddress: PatientAddress

只有当你的所有属性都已经初始化时，一个空的 init 才会起作用，这意味着你需要为你的 patientAddress 分配一些值：

@Published var patientAddress = PatientAddress()

但是，要使其正常工作，您还需要在 PatientAddress 中添加一个空的 init：

struct PatientAddress {
    ...
    init() {}
}

---

注意

如果没有所有这些初始化程序，您的所有代码都可以简单得多。如果您只使用空的 init 方法，则不必声明它们（如果没有其他初始化程序，它们会为结构自动生成）：

class PatientData: Identifiable, ObservableObject {
    let id = UUID()

    @Published var patientName: String = "Name"
    @Published var patientAge: String = "Age"
    @Published var patientDOB: String = "DOB"
    @Published var patientPhone: String = "Phone"
    @Published var patientAddress: PatientAddress = PatientAddress()

    @Published var facilityName: String = "Facility"
    @Published var facilityRoom: String = "Room Number"
    @Published var facilityFloor: String = "Floor"
    @Published var facilityPhoneNumber: String = "Phone Number"
}

extension PatientData {
    struct PatientAddress {
        var patientStreetAddress: String = "Street"
        var patientCity: String = "City"
        var patientState: String = "State"
        var patientZip: String = "Zip"
    }
}

此外，Swift 可以自动推断类型。您通常不必显式声明类型：

@Published var patientPhone = "Phone"
@Published var patientAddress = PatientAddress()