在iOS Swift中点击下一步按钮时如何在表格视图中加载数据数组？

Question

我尝试在 tableview 中加载数组项详细信息。在 tableview 中，我列出了标签数组。并在导航栏上放置了两个按钮，分别是Next和previous

当用户点击 next 时，它将替换 tableview 中的数组标签值，或者如果用户点击 previous，它将替换 tableview 中的数组标签值。

为了从 json 获取数据，我使用的是 SwiftyJson。这是我的 json 响应值：

    "results": [
  {

   "PoDocNo": "4500022400",
   "Item": "00010",
   "Material": "RMECC_MOB1",
   "StorageLocation": "3001",
   "MatGroup": "00107",
    "Quantity": "2.000",
   "OrderUnit": "KG",
   "NetPrice": "1000.000",
   "UnitofPrice": "1.000",
   "ItemCat": "0",
   "Requistor": ""
   },
   {

   "PoDocNo": "4500022400",
   "Item": "00020",
    "Material": "RMECC_MOB1",
    "StorageLocation": "3001",
   "MatGroup": "00107",
   "Quantity": "2.000",
   "OrderUnit": "KG",
   "NetPrice": "1000.000",
   "UnitofPrice": "1.000",
   "ItemCat": "0",
   "Requistor": ""
   }
  ] 

这是我的屏幕截图：

这是我的模型：

    import Foundation
    import SwiftyJSON

   class PoVendorModel {

   var Material: String?
    var Description: String?
   var FixedVendor: String?
var VendorName: String?
var PurchOrg: String?
var PurchGroup : String?
var valuationPrice : String?
var Qty: String?
var UoM:String?

var totalValue: String?
var DeliveryDate: String?
var MatGrp: String?
var Plant: String?
var StorageLocation: String?
var ReqTrack: String?
var AAC: String?
var ItemCategory: String?
var GLAccount: String?
var CostCenter: String?
var Order: String?
var WBS: String?
var ProfitCenter: String?
var lineNo: String?

init(json: JSON) {

    Material = json["Material"].stringValue
    Qty = json["Quantity"].stringValue
    UoM = json["OrderUnit"].stringValue
    totalValue = json["NetPrice"].stringValue
    AAC = json["shrtText"].stringValue
    StorageLocation = json["StorageLocation"].stringValue
    MatGrp = json["MatGroup"].stringValue
    valuationPrice = json["NetPrice"].stringValue
    ItemCategory = json["ItemCat"].stringValue

    lineNo = json["Item"].stringValue

}

func getProperty(at index: Int) -> String {

    switch index {
    case 0:
        return self.Material ?? ""
    case 1:
        return self.Description ?? ""
    case 2:
        return self.FixedVendor ?? ""
    case 3:
        return self.VendorName ?? ""
    case 4:
        return self.PurchOrg ?? ""
    case 5:
        return self.PurchGroup ?? ""
    case 6:
        return self.Qty ?? ""
    case 7:
        return self.valuationPrice ?? ""
    case 8:
        return self.totalValue ?? ""
    case 9:
        return self.DeliveryDate ?? ""
    case 10:
        return self.MatGrp ?? ""
    case 11:
        return self.Plant ?? ""
    case 12:
        return self.StorageLocation ?? ""
    case 13:
        return self.ReqTrack ?? ""
    case 14:
        return self.AAC ?? ""
    case 15:
        return self.ItemCategory ?? ""
    case 16:
        return self.GLAccount ?? ""
    case 17:
        return self.CostCenter ?? ""
    case 18:
        return self.Order ?? ""
    case 19:
        return self.WBS ?? ""
    case 20:
        return self.ProfitCenter ?? ""
    case 21:
        return self.UoM ?? ""

    default:
        return "Error"
    }

  }

 }

当我点击表格视图标签值中的下一个按钮时，如何替换值数组？

Answer 1

无论处理您的“下一个”和“上一个”点击的对象都应该知道您的所有数据和当前的“页码”。给你的 tableView 一个PoVendorModel 类型的属性（如果它还没有）。点击 Next 或 Previous 可以更新页码，索引到模型数组并将相关的分配给 tableView。 tableView 可以对此做出反应并在值更改时自行更新。

无论处理下一次/上一次点击：

var allVendors: [PoVendorModel]

var pageNumber: Int = 0 {
    didSet {
        tableViewController.vendorData = allVendors[pageNumber]
    }
}

func nextTapped() {
    pageNumber = min(allVendors.count - 1, pageNumber + 1)
}

func previousTapped() {
    pageNumber = max(0, pageNumber - 1)
}

在你的 UITableViewController 中：

// A property of your UITableViewController
var vendorData: PoVendorModel? = nil {
    didSet {
        tableView?.reloadData()
    }
}

Answer 2

首先，不要手动解析所有JSON响应，而是使用Codable。

您应该创建的模型，

struct Root: Decodable {
    let vendors: [PoVendorModel]

    enum CodingKeys: String, CodingKey {
        case vendors = "results"
    }
}

struct PoVendorModel: Decodable {
    let poDocNo, item, material, storageLocation, matGroup, quantity, orderUnit, netPrice, unitofPrice, itemCat, requistor: String

    enum CodingKeys: String, CodingKey {
        case poDocNo = "PoDocNo"
        case item = "Item"
        case material = "Material"
        case storageLocation = "StorageLocation"
        case matGroup = "MatGroup"
        case quantity = "Quantity"
        case orderUnit = "OrderUnit"
        case netPrice = "NetPrice"
        case unitofPrice = "UnitofPrice"
        case itemCat = "ItemCat"
        case requistor = "Requistor"
    }
}

解析 JSON 数据 使用上面创建的模型，

if let data = data {
    do {
        let root = try JSONDecoder().decode(Root.self, from: data)
        self.vendors = root.vendors //created in viewController
    } catch {
        print(error)
    }
}

在ViewController 中，为vendors 和您将用于tableView's dataSource 的dataSource 实例创建属性。此外，维护一个currentIndex，它将跟踪tableView 中可见的当前vendor。

class VC: UIViewController {
    @IBOutlet weak var tableView: UITableView!

    var currentIndex: Int = 0

    var vendors = [PoVendorModel]() {
        didSet {
            self.dataSource = vendors.first
        }
    }

    var dataSource: PoVendorModel? {
        didSet {
            self.tableView.reloadData()
        }
    }
}

next 和 previous 按钮的 button 操作类似于，

@IBAction func onTapNextButton(_ sender: UIButton) {
    let nextIndex = min(currentIndex+1, vendors.count)
    if nextIndex != currentIndex {
        self.dataSource = vendors[nextIndex]
        currentIndex = nextIndex
    }
}

@IBAction func onTapPreviousButton(_ sender: UIButton) {
    let previousIndex = max(0, currentIndex-1)
    if previousIndex != currentIndex {
        self.dataSource = vendors[previousIndex]
        currentIndex = previousIndex
    }
}