arrays - Swift - Tableview 在第二次加载后无法正确重新加载

Question

我对我的 Tableview 的 react 有点困惑。我的问题是，Tableview 显示的顺序与打印词典时的词典不同。当我打印字典时，一切似乎都很好，但是当我查看手机时，表格 View 再次以随机顺序显示单元格。

首先我获取 JSON。

    var Aanbiedingen_bieren = [Aanbiedingen_bier]()
    var Aanbiedingen_bieren_Filter = [Aanbiedingen_bier]()

获取数据。

func fetchData() {
    Aanbiedingen_bieren_Filter.removeAll()
    Aanbiedingen_bieren.removeAll()
    let url_Aanbiedingen_bier = URL(string: "\(Firebase_url)")
    let downloadURL = url_Aanbiedingen_bier
    URLSession.shared.dataTask(with: downloadURL!) { data, urlResponse, error in
        let data = data
        print("downloaded")
        do
        {
            let decoder = JSONDecoder()
            let downloadedBiers = try decoder.decode(SheetJS.self, from: data!)
            self.Aanbiedingen_bieren = downloadedBiers.SheetJS

            for jsonData in self.Aanbiedingen_bieren {
                let Soort = jsonData.Title
                if self.Soort_Bier == "Alles" {
                    self.Aanbiedingen_bieren_Filter.append(jsonData)
                }else{
                    if self.Soort_Bier == "Krat" {
                        if Soort.contains(word: "Krat") {
                            self.Aanbiedingen_bieren_Filter.append(jsonData)
                        }
                    }
                    if self.Soort_Bier == "Fles" {
                        if Soort.contains(word: "Fles") {
                            self.Aanbiedingen_bieren_Filter.append(jsonData)
                        }
                    }
                }
            }
            self.Aanbiedingen_bieren_Filter = self.Aanbiedingen_bieren_Filter.sorted(by: {$0.Voor_prijs.compare($1.Voor_prijs, options: .numeric) == .orderedAscending})
            print(self.Aanbiedingen_bieren_Filter)
            DispatchQueue.main.async {
                self.tableView.reloadData()
            }
        } catch {
            print(error)
        }
    }.resume()
}

代码第一次运行Soort_Bier = "Alles"。点击按钮后，Soort_Bier 将更改为 Soort_bier = "Krat"。第二次加载数据后，我首先想过滤数据。我通过实现一个 if 语句来完成此操作，该语句检查 JSON 的标题在字符串中是否具有特定单词，如果是，则将其附加到另一个数组。之后我想整理一下价格。排序完成后，我想打印字典以查看排序是否正确。情况似乎仍然如此。然后我想重新加载 tableView，以便所有单元格都会显示，但这里出了问题。当我想第二次加载字典时，它似乎没有正确地重新加载tableView。

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return Aanbiedingen_bieren_Filter.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "Aanbiedingen_bieren_Cell", for: indexPath) as! Aanbiedingen_bieren_Cell

        let Aanbiedingen_bier = self.Aanbiedingen_bieren_Filter[indexPath.row]
        cell.Aanbiedingen_bier = Aanbiedingen_bier

        return cell
    }

结构:

struct SheetJS: Codable {
    var SheetJS: [Aanbiedingen_bier]

    init(SheetJS: [Aanbiedingen_bier]) {
        self.SheetJS = SheetJS
    }
}

struct Aanbiedingen_bier: Codable {
    let Logo_Image: String
    let Van_prijs: String
    let Voor_prijs: String
    let Beschrijving: String
    let Item_Image: String
    let Title: String
    let Bestel_Online_link: String
    let Footer_item: String
    let Item_1: String
    let Item_2: String

    init(Logo_Image: String, Item_Image: String, Van_prijs: String, Voor_prijs: String, Beschrijving: String, Title: String, Item_1: String, Item_2: String, Bestel_Online_link: String, Footer_item: String) {
        self.Logo_Image = Logo_Image
        self.Title = Title
        self.Item_Image = Item_Image
        self.Beschrijving = Beschrijving
        self.Van_prijs = Van_prijs
        self.Voor_prijs = Voor_prijs
        self.Item_1 = Item_1
        self.Item_2 = Item_2
        self.Bestel_Online_link = Bestel_Online_link
        self.Footer_item = Footer_item

    }
}

JSON:

{
  "SheetJS": [
    {
      "Logo_Image": "https://www.biernet.nl/images/winkel/17335-agrimarkt.gif",
      "Van_prijs": "€16,99",
      "Voor_prijs": "€10,49",
      "Beschrijving": "Krat 24x0,30",
      "Item_Image": "https://www.biernet.nl/images/soort/23026-grolsch%20krat%20normale%20flesjes%2030%20cl.png",
      "Title": "Grolsch Premium Pilsener",
      "Bestel_Online_link": "",
      "Footer_item": "t/m zaterdag 3 augustus",
      "Item_1": "€6,50 korting (38%)",
      "Item_2": "€1,46 per liter"
    },//Some more data
  ]
}

仅打印词典的价格:

€5,39
€5,94
€6,39
€6,39
€7,64
€16,19

Result

如果您需要更多信息或代码，请告诉我。

Answer 1

这是因为字典中的项目是随机排序的。

如果您想订购它，您应该使用“设置”另一个订购的集合类型。

或者查看下面的 Apple 文档

Apple Docs : The order of key-value pairs in a dictionary is stable between mutations but is otherwise unpredictable. If you need an ordered collection of key-value pairs and don’t need the fast key lookup that Dictionary provides, see the KeyValuePairs type for an alternative.