使用结构体数组实现Swift / iOS searchBar时遇到问题

Question

我有一个用于填充表格视图的结构数组。但是我无法使我的searchBar正常工作。我最初的searchBar代码是在使用更多“基本”数组时创建的。转换为struct后，它将不再起作用。我从Xcode收到3个错误。我用//

import UIKit

struct Material {

var name : String
var lbft : String
var gcm : String

}

class ViewController: UIViewController {

    @IBOutlet weak var searchBar: UISearchBar!

    @IBOutlet var tableView: UITableView!

    let materialData = [
        Material(name: "Acetaminohen Powder, Unmilled",    lbft: "43",    gcm: "0.688794"),
        Material(name: "Acetylene Black, 100% Compressed",    lbft: "35",    gcm: "0.560646"),
        Material(name: "Acetylsalicyic Acid",    lbft: "20",    gcm: "0.320369"),
        Material(name: "Acrylamide",    lbft: "34",    gcm: "0.54463"),
        Material(name: "Acrylic Granules, Coarse",    lbft: "40",    gcm: "0.64"),
        Material(name: "Acrylic Granules, Fine",    lbft: "36",    gcm: "0.58"),
        Material(name: "Acrylonitrile Butadien Styrene (Abs) Resin",    lbft: "50",    gcm: "0.8"),
        Material(name: "Acrylonitrile Butadiene Styrene (Abs) Granules",    lbft: "36",    gcm: "0.58"),
        Material(name: "Activated Alumina",    lbft: "42.5",    gcm: "0.68"),
        Material(name: "Activated Carbon",    lbft: "32.5",    gcm: "0.52"),
        Material(name: "Actylene Black",    lbft: "45.5",    gcm: "0.73"),
        Material(name: "Aero Xanthates",    lbft: "112.5",    gcm: "1.8"),
        Material(name: "Aerolyte",    lbft: "51",    gcm: "0.82"),
        Material(name: "Aerosil, Fumed Silica",    lbft: "32",    gcm: "0.51"),
        Material(name: "Aerosil, Silicon Dioxide",    lbft: "30",    gcm: "0.48"),
        Material(name: "Alaluren",    lbft: "112",    gcm: "1.79")]

    var searchMaterial = [String]()
    var searching = false

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.delegate = self
        tableView.dataSource = self

    }
}

extension ViewController: UITableViewDelegate {

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.deselectRow(at: indexPath, animated: true)
    }
}

extension ViewController: UITableViewDataSource {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if searching {
        return searchMaterial.count
        } else {
        return materialData.count
    }
}

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        cell.textLabel?.numberOfLines = 0
        if searching {
            cell.textLabel?.text = searchMaterial[indexPath.row]
        } else {
            cell.textLabel?.text = materialData[indexPath.row] // <-- ERROR Cannot assign value of type 'Material' to type 'String'
        }
        return cell
    }

}

extension ViewController: UISearchBarDelegate {
    func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
        searchBar.setShowsCancelButton(true, animated: true)
        searchMaterial = materialData.filter({$0.prefix(searchText.count) == searchText}) // <-- ERROR Cannot assign value of type '[Material]' to type '[String]'
                                                                                          // <-- ERROR Value of type 'Material' has no member 'prefix'
        searching = true
        tableView.reloadData()

    }

    func searchBarCancelButtonClicked(_ searchBar: UISearchBar) {
        searchBar.setShowsCancelButton(false, animated: true)
        searching = false
        searchBar.text = ""
        tableView.reloadData()

    }

}

Answer 1

没有

materialData[0] etc...

声明您的数组，例如

var searchMaterial:[String] = []

然后您可以像访问它一样

searchMaterial[indexPath.row]

Answer 2

1）cell.textLabel？.text = materialData [indexPath.row]materialData [indexPath.row]将为您提供材料类型而不是字符串的对象。不知道您期望什么值。但是将其更改为

materialData[indexPath.row].name

2）searchMaterial = materialData.filter（{$ 0.prefix（searchText.count）== searchText}）//

更改为

   var searchMaterial:[Material] = []
   searchMaterial = materialData.filter { $0.name.contains(searchText) }