How to correctly use the selector in swift 3 programming language

Question

I am new to swift 3 and have read some part of Ray Wenderlich's iOS apprentice part 3(My Locations). I have pass through the sample code with the hint help of Xcode 8. But when I came to page 120, saying some of selector, I cannot pass through correctly running of Xcode 8. It complaints with error message as following:

2016-10-07 11:10:57.975 test051_MyLocations[2732:65640] -[test051_MyLocations.TagLocationViewController hideKeyboard]: unrecognized selector sent to instance 0x7f96005165f0

The following is my code:

func hideKeyboard(gestureRecognizer: UIGestureRecognizer) {
    let point = gestureRecognizer.location(in: tableView)
    let indexPath = tableView.indexPathForRow(at: point)

    if indexPath != nil && indexPath!.section == 0
        && indexPath!.row == 0 {
        return
    }

    descriptionTextView.resignFirstResponder()
}

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
    descriptionTextView.text = ""
    categoryLabel.text = categoryName

    latitudeLabel.text = String(format: "%.8f", coordinate.latitude)
    longitudeLabel.text = String(format: "%.8f", coordinate.longitude)

    if let placemark = placemark {
        addressLabel.text = stringFromPlacemark(placemark: placemark)
    } else {
        addressLabel.text = "No Address Found"
    }

    dateLabel.text = formatDate(date:Date() as NSDate)

    // let hideKeyboard = "hideKeyboard:"
    // let selector = Selector(hideKeyboard)
    // let selector = Selector({"hideKeyboard:"}())
    let gestureRecognizer = UITapGestureRecognizer(target: self,action: Selector({"hideKeyboard"}()))
    // I have tried with a : character appended after hideKeyboard, but I still failed to run the program.

    gestureRecognizer.cancelsTouchesInView = false

    tableView.addGestureRecognizer(gestureRecognizer)
}