ios - 如何使用 Swift 类在数组中添加信息

Question

我在向数组中添加一些信息时遇到了问题。

我的类 Flights 由以下定义:

class Flight{
let date: String
let type: String
let regi: String

let totalTime: String

let depTime: String
let depPlace: String

let arrTime: String
let arrPlace: String

init(from dat: String, _ typ: String, _ reg: String, _ totaltim: String, _ depTim: String, _ depPlac: String, _ arrTim: String, _ arrPlac: String) {
    self.date = dat
    self.type = typ
    self.regi = reg

    self.totalTime = totaltim

    self.depTime = depTim
    self.depPlace = depPlac

    self.arrTime = arrTim
    self.arrPlace = arrPlac
}}

在我的主要代码中，我已经像这样声明了我的数组:

var datas: [Flight] = []

最后我用这段代码添加了一些来自 firebase 的信息:(我添加了一些注释来向您展示 print() 结果)

if let user = Auth.auth().currentUser{
        // user is connect
        let ref = Database.database().reference()
        let userID = Auth.auth().currentUser?.uid

        let ev = ref.child("flights").child(userID!)

        ev.observe(.childAdded, with: { (snapshot) -> Void in
        let flightKey = snapshot.key

        ref.child("flights").child(userID!).child(flightKey).observeSingleEvent(of: .value) {(snapshot) in
            let value = snapshot.value as? NSDictionary

            let date = value?["Date"] as? String ?? "no date"
            let type = value?["aircraft-model"] as? String ?? "no type"
            let registration = value?["aircraft-registration"] as? String ?? "no callsign"
            let totalTime = value?["TOTAL-TIME"] as? String ?? "no total Time"
            let deppartTime = value?["departure-time"] as? String ?? "no departure Time"
            let deppartPlace = value?["departure-place"] as? String ?? "no departure Place"
            let arrivalTime = value?["arrival-time"] as? String ?? "no arrival Time"
            let arrivalPlace = value?["arrival-place"] as? String ?? "no arrival Place"

            print("Date : \(date) - type : \(type) - registration : \(registration) - Etc ...")// Give me exactly the value I requested


            self.datas.append(Flight(from: date, type, registration, totalTime, deppartTime, deppartPlace, arrivalTime, arrivalPlace))


            print(self.datas)// Give me "MyProjectName.Flight ...
            }

        })

    }else{
        // si non connecté alors DECONNEXION !!!!
        fatalError("error ...")
    }

所以我不明白为什么如果我打印从 firebase 接收到的值它可以工作但是如果我打印由 firebase 接收到的值完成的数组值它不起作用？

感谢您的帮助!

传单 74

Answer 1

欢迎 :)

我认为一切都如预期的那样，你看到这个只是因为 Swift 不知道如何描述你的对象。

要解决此问题，您应该在 Flight 类 ( https://developer.apple.com/documentation/swift/customstringconvertible ) 中实现 CustomStringConvertible 协议(protocol)

有点像

extension Flight: CustomStringConvertible {
    var description: String {
        var description = ""
        description.append("date: \(date)\n")
        description.append("type: \(type)\n")
        description.append("regi: \(regi)\n")
        //and so on
        return description
    }
}

应该给你你正在寻找的东西。

希望对你有帮助