本文將演示如何給表格新增索引功能。

在專案導航區，開啟檢視控制器的程式碼檔案【ViewController.swift】

現在開始編寫程式碼，建立一個表格，並在表格右側新增一列快捷索引。

  1 import UIKit
  2 
  3 //使當前的檢視控制器類，遵循表格的資料來源協議UITableViewDataSource
  4 class ViewController: UIViewController, UITableViewDataSource {
  5 
  6     //建立一個字典物件，作為表格的資料來源。字典中的鍵，將作為表格的索引列表。
  7     var
 
 countries :Dictionary<String, [String]> = ["A": ["Afghanistan", "Albania", "Algeria", "Angola", "Australia", "Austria", "Azerbaijan"],
  8     "B":["Bangladesh","Belgium","Bhutan","Bolivia","Brazil","Bahrain","Bulgaria"], 
  9     "C":["Canada","Congo","Chile","China","Colombia","Cuba"], 
 
 10     "D":["Denmark","Djibouti","Dominica"],
 11     "E":["Egypt","Estonia","Ethiopia"], 
 12     "F":["Fiji","Finland","France"], 
 13     "G":["Gambia","Germany","Greece"],
 14     "H":["Haiti","Honduras","Hungary"], 
 15     "I":["India","Indonesia","Iran","Ireland","Iraq","Italy"], 
 16     "
 
J":["Jordan","Japan"],
 17     "K":["Kazakhstan","Korea","Kuwait"], 
 18     "L":["Laos","Libya","Lebanon"], 
 19     "M":["Madagascar","Morocco","Malaysia","Mexico","Mali","Mozambique"],
 20     "N":["Nepal","Netherlands","Nigeria","New Zealand"],
 21     "O":["Oman"], 
 22     "P":["Pakistan","Panama","Philippines","Portugal"], 
 23     "Q":["Qatar"],
 24     "R":["Romania","South Africa","Russia"],
 25     "S":["Serbia & Montenegro","Senegal","Singapore","Somalia","Switzerland"],
 26     "T":["Thailand","Turkmenistan","Tunisia","Turkey"],
 27     "U":["United Arab Emirates","United States of America","Uzbekistan"], 
 28     "V":["Vanuatu","Venezuela","Vietnam"], 
 29     "Y":["Yemen"],
 30     "Z":["Zambia","Zimbabwe"]]
 31     
 32     //建立一個字串陣列，作為當前類的另一個屬性
 33     var keys:[String] = []
 34 
 35     override func viewDidLoad() {
 36         super.viewDidLoad()
 37         // Do any additional setup after loading the view, typically from a nib.
 38         
 39         //將字典的鍵轉換為陣列，並執行升序排列，這個陣列將被作為索引使用
 40         keys = Array(countries.keys).sorted()
 41 
 42         //獲得裝置的螢幕尺寸
 43         let screenRect = UIScreen.main.bounds
 44         //建立一個矩形區域，作為表格檢視的顯示區域。
 45         let tableRect = CGRect(x: 0,
 46                                y: 20, 
 47                                width: screenRect.size.width, 
 48                                height: screenRect.size.height - 20)
 49         //初始化一個指定顯示區域的表格物件
 50         let tableView = UITableView(frame: tableRect)
 51         
 52         //設定表格物件的資料來源為當前的檢視控制器物件
 53         tableView.dataSource = self
 54         //並將表格檢視新增到根檢視中
 55         self.view.addSubview(tableView)
 56     }
 57     
 58     //新增一個代理方法，用來設定表格的段落的數量
 59     func numberOfSections(in tableView: UITableView) -> Int
 60     {
 61         //在此設定段落的數量，等於字典中鍵的數量
 62         return keys.count
 63     }
 64     
 65     //新增一個代理方法，用來設定表格的行數
 66     func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
 67     {
 68         //獲得當前段落的序號，
 69         let subCountries = countries[keys[section]]
 70         //然後獲得在字典中，對應的值的數量
 71         //以該數量作為當前段落的行數
 72         return (subCountries?.count)!
 73     }
 74     
 75     //新增一個代理方法，用來設定表格的段落標題
 76     func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String?
 77     {
 78         return keys[section]
 79     }
 80     
 81     //新增一個代理方法，用來設定表格索引的標題陣列
 82     func sectionIndexTitles(for tableView: UITableView) -> [String]?
 83     {
 84         return keys
 85     }
 86     
 87      //新增一個代理方法，用來初始化或複用表格中的單元格
 88     func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
 89     {
 90         //建立一個字串常量，作為單元格的複用標識
 91         let identifier = "reusedCell"
 92         //根據複用標識，從表格中獲得可以複用的單元格
 93         var cell = tableView.dequeueReusableCell(withIdentifier: identifier)
 94         
 95         //如果沒有可以複用的單元格
 96         if(cell == nil)
 97         {
 98             //則初始化一個預設樣式的單元格，並設定單元格的複用標識
 99             cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: identifier)
100         }
101         
102         //根據當前單元格的段落序號，獲得國家名稱列表
103         let subCountries = countries[keys[(indexPath as NSIndexPath).section]]
104         //根據當前單元格的序號，獲得該單元格需要顯示的國家名稱
105         cell?.textLabel?.text = subCountries![(indexPath as NSIndexPath).row]
106         
107         //返回設定好的單元格
108         return cell!
109     }
110 
111     override func didReceiveMemoryWarning() {
112         super.didReceiveMemoryWarning()
113         // Dispose of any resources that can be recreated.
114     }
115 }