ios - UITableView 无法使用 Swift 3 中的 Index 正确显示数据

Question

我的应用程序项目中有一个 UITableView，它从数组中提取数据。此数据也必须编入索引。但由于某种原因，数据没有显示在适当的部分，即 A、B 等。我似乎看不出有什么问题。到目前为止我的数据是:

import Foundation
import UIKit

class uniVC: UITableViewController {


    let university = ["Allcat University", "Allday University", "Bejnamin University", "Cat University"]

    var universitySections = [String]()
    var wordsDict = [String:[String]]()

    let wordIndexTitles = ["a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"]

    func generateWordsDict() {

        for word in university {

            let key = "\(word[word.startIndex])"
            let lower = key.lowercased()

            if var wordValues = wordsDict[lower] {
                wordValues.append(word)
                wordsDict[lower] = wordValues
            } else {
                wordsDict[lower] = [word]
            }

        }

        universitySections = [String](wordsDict.keys)
        universitySections = universitySections.sorted()

    }

    override func viewDidLoad() {
        super.viewDidLoad()

        generateWordsDict()


    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()
        //Dispose
    }

    // Mark table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        return universitySections.count
    }

    override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return universitySections[section]
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        let wordKey = universitySections[section]
        if let wordValues = wordsDict[wordKey] {
            return wordValues.count
        }

        return 0
    }


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

        let wordKey = universitySections[indexPath.section]
        if wordsDict[wordKey.lowercased()] != nil {

            cell.textLabel?.text = university[indexPath.row]

        }

        return cell
    }

    override func sectionIndexTitles(for tableView: UITableView) -> [String]? {
        return wordIndexTitles
    }

    override func tableView(_ tableView: UITableView, sectionForSectionIndexTitle title: String, at index: Int) -> Int {

        guard let index = universitySections.index(of: title) else {
            return -1
        }

        return index

    }
}

对此有什么想法吗？

Answer 1

一切都很好，除了:

if wordsDict[wordKey.lowercased()] != nil {
    cell.textLabel?.text = university[indexPath.row]
}

我认为你犯了一个错误。让更改为:

if let wordValues = wordsDict[wordKey] {
    cell.textLabel?.text = wordValues[indexPath.row]
}

这是结果: