Swift - 将struct数组传递给另一个struct的init

Question

如何初始化包含另一个结构数组的结构？

我想创建一个Invoice条目，其中包含所有属性和具有InvoiceItem数组的项目。

此外，当发票仍为草稿时，项目可以为空。

使用发票数据和项目从服务器读取JSON响应正常。

关于viewcontroller的保存动作我有：

var invoice: Invoice?
var client: Client?
var invoiceItems : [InvoiceItem] = [InvoiceItem]()

@IBAction func saveInvoice(_ sender: Any) {

...

invoice = Invoice(invoice_id: invoice?.invoice_id, client_id: client_id, tax: 0.00, date_issue: dateIssue, due_date: dueDate,
amount_paid: 0.00,
date_transaction: "0000-00-00",
voided: 0,
note: "",
invoice_number: "",
status: "",
items: invoiceItems
)

override func viewDidLoad() {

...
 invoiceItems = (invoice?.items)!
...
}

我收到此错误：无法将类型'[InvoiceItem]'的值转换为预期的参数类型'InvoiceItem'，在线：items：invoiceItems

struct InvoiceItem: Codable {
    var invoice_detail_id: Int!
    let description: String!
    let unit_price: Decimal!
    let quantity: Decimal!

    init(invoice_detail_id: Int! = nil, description: String, unit_price: Decimal, quantity: Decimal) {
        self.invoice_detail_id = invoice_detail_id
        self.description = description
        self.unit_price = unit_price
        self.quantity = quantity
    }
}

struct Invoice: Codable {
    var invoice_id: Int!
    let client_id: Int!
    let tax: Decimal!
    let date_issue: String!
    let due_date: String!
    let amount_paid: Decimal!
    let date_transaction: String!
    let voided: Int!
    let note: String!
    let invoice_number: String!
    let status: String!
    let items: [InvoiceItem]!

    init(invoice_id: Int! = nil, client_id: Int! = nil,tax: Decimal, date_issue: String, due_date: String, amount_paid: Decimal, date_transaction: String, voided: Int, note: String, invoice_number: String, status: String, items: InvoiceItem) {
        self.invoice_id = invoice_id
        self.client_id = client_id
        self.tax = tax
        self.date_issue = date_issue
        self.due_date = due_date
        self.amount_paid = amount_paid
        self.date_transaction = date_transaction
        self.voided = voided
        self.note = note
        self.invoice_number = invoice_number
        self.status = status
        self.items = [items]
    }


}

Answer 1

您的发票init已将items: InvoiceItem作为参数。项目的类型是InvoiceItem，而不是InvoiceItem阵列。

将类型更改为InvoiceItem数组。

编辑：

在您的Invoice init中，您有：

self.items = [items]

你试图将一个InvoiceItem数组传递给一个定义为items: InvoiceItem的参数。

这显然不起作用，所以我告诉你将参数类型更改为InvoiceItem数组。

现在你有了，你正在将数组中的InvoiceItem包装起来。所以你有一个InvoiceItem数组的数组。

将该行代码更改为：

self.items = items

Answer 2

让我们用显式名称命名方法，并添加一个，因为您正在混合数组和唯一对象。

我建议：

init(invoice_id: ... status: String, anItem: InvoiceItem)
{
   ...
   self.items = [anItem]
}

init(invoice_id: ... status: String, multipleItems: [InvoiceItem])
{
   ...
   self.items = multipleItems
}

在你的代码中，因为它是var invoiceItems : [InvoiceItem] = [InvoiceItem]()，我会使用第二个，因为它是一个InvoiceItem数组。

invoice = Invoice(invoice_id: invoice?.invoice_id,
                  client_id: client_id,
                  tax: 0.00,
                  date_issue: dateIssue,
                  due_date: dueDate,
                  amount_paid: 0.00,
                  date_transaction: "0000-00-00",
                  voided: 0,
                  note: "",
                  invoice_number: "",
                  status: "",
                  multipleItems: invoiceItems
                  )

我不知道你是否还想使用第一个，但万一你可以使用keep。请避免在这两种方法之间重复代码，第一种方法可以使用init(... multipleItems:[anItem])调用第二种方法。