NSAttributedStringKey giving an unresolved identifier error

Question

I\'m following an online tutorial to build a magazine type iOS application. I\'m attempting to use NSAttributedStringKey but keep getting the error shown below. Any ideas?

Answer 1

Swift 4.x

 // MARK: - Deal with the empty data set
// Add title for empty dataset
func title(forEmptyDataSet _: UIScrollView!) -> NSAttributedString! {
    let str = "Welcome"
    let attrs = [NSAttributedStringKey.font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.headline)]
    return NSAttributedString(string: str, attributes: attrs)
}

// Add description/subtitle on empty dataset
func description(forEmptyDataSet _: UIScrollView!) -> NSAttributedString! {
    let str = "Tap the button below to add your first grokkleglob."
    let attrs = [NSAttributedStringKey.font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.body)]
    return NSAttributedString(string: str, attributes: attrs)
}

// Add your image
func image(forEmptyDataSet _: UIScrollView!) -> UIImage! {
    return UIImage(named: "MYIMAGE")
}

// Add your button
func buttonTitle(forEmptyDataSet _: UIScrollView!, for _: UIControlState) -> NSAttributedString! {
    let str = "Add Grokkleglob"
    let attrs = [NSAttributedStringKey.font: UIFont.preferredFont(forTextStyle: UIFontTextStyle.callout), NSAttributedStringKey.foregroundColor: UIColor.white]
    return NSAttributedString(string: str, attributes: attrs)
}

// Add action for button
func emptyDataSetDidTapButton(_: UIScrollView!) {
    let ac = UIAlertController(title: "Button tapped!", message: nil, preferredStyle: .alert)
    ac.addAction(UIAlertAction(title: "Hurray", style: .default, handler: nil))
    present(ac, animated: true, completion: nil)
}