我正在尝试实现自动补全功能，但是找不到在Swift中可用的示例。下面，我打算转换Ray
Wenderlich的自动完成教程和2010年的示例代码。最后，代码进行了编译，但是没有显示包含可能完成的表格，而且我没有经验来了解为什么它未被隐藏shouldChangeCharactersInRange。

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource, UITextFieldDelegate {

@IBOutlet weak var textField: UITextField!
let autocompleteTableView = UITableView(frame: CGRectMake(0,80,320,120), style: UITableViewStyle.Plain)

var pastUrls = ["Men", "Women", "Cats", "Dogs", "Children"]
var autocompleteUrls = [String]()

override func viewDidLoad() {
    super.viewDidLoad()

    autocompleteTableView.delegate = self
    autocompleteTableView.dataSource = self
    autocompleteTableView.scrollEnabled = true
    autocompleteTableView.hidden = true
}

func textField(textField: UITextField!, shouldChangeCharactersInRange range: NSRange, replacementString string: String!) -> Bool
{
    autocompleteTableView.hidden = false
    var substring = (textField.text as NSString).stringByReplacingCharactersInRange(range, withString: string)

    searchAutocompleteEntriesWithSubstring(substring)
    return true     // not sure about this - could be false
}

func searchAutocompleteEntriesWithSubstring(substring: String)
{
    autocompleteUrls.removeAll(keepCapacity: false)
    var indexOfPastUrls = 0

    for curString in pastUrls
    {
        let substringRange = curString.rangeOfString(curString)

        if (indexOfPastUrls  == 0)
        {
            autocompleteUrls.append(curString)
        }
        indexOfPastUrls = indexOfPastUrls + 1
    }
    autocompleteTableView.reloadData()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
}

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

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    let autoCompleteRowIdentifier = "AutoCompleteRowIdentifier"
    var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier(autoCompleteRowIdentifier, forIndexPath: indexPath) as UITableViewCell
    let index = indexPath.row as Int

    cell.textLabel.text = autocompleteUrls[index]
    return cell
}

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    let selectedCell : UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
    textField.text = selectedCell.textLabel.text        
}
}