在 struct init 期间无法填充 Swift 属性

Question

我有以下代码。

出于某种原因，当我初始化 VerifyPhoneView 类时，它会正确打印验证 ID，但 self.verificationID 仍然是空字符串。

什么可能导致这种情况？

struct VerifyPhoneView: View {

    private var phoneNumber: String
    @State private var verificationID: String = ""

    init(phoneNumber: String, verificationID: String) {
        self.phoneNumber = phoneNumber

        print ("Initializer, verificationID: " + verificationID)

        self.verificationID = verificationID
        print ("Initializer, self.verificationID: " + self.verificationID)
    }
}

Answer 1

在这种情况下，不需要状态的默认值。这是一个解决方案:

struct VerifyPhoneView: View {

    private var phoneNumber: String
    @State private var verificationID: String    // << here !!
    ...
    init(phoneNumber: String, verificationID: String) {
        self.phoneNumber = phoneNumber

        print ("Initializer, verificationID: " + verificationID)

        _verificationID = State(initialValue: verificationID) // << here !!
        print ("Initializer, self.verificationID: " + self.verificationID)
    }