ios - Getting autocomplete to work in swift

Question

I am trying to implement autocompletion, but can't find an example that works in Swift. Below, I'm tring to convert Ray Wenderlich's autocompletion tutorial and example code from 2010. Finally, the code compiles, but the table containing possible completions does not appear, and I don't have the experience to see why it is not unhidden by 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        
}
}

Answer 1

Replace your searchAutocompleteEntriesWithSubstring function content with the one below. I hope it would help you.

func searchAutocompleteEntriesWithSubstring(substring: String)
{
    autocompleteUrls.removeAll(keepCapacity: false)

    for curString in pastUrls
    {
        var myString:NSString! = curString as NSString

        var substringRange :NSRange! = myString.rangeOfString(substring)

        if (substringRange.location  == 0)
        {
            autocompleteUrls.append(curString)
        }
    }

    autocompleteTableView.reloadData()
}