您需要将添加UITapGestureRecognizer到UITextView您希望能够点击的。您目前正在将添加UITapGestureRecognizer到ViewController的中view。这就是演员阵容让您陷入困境的原因。您正在尝试将UIView转换为UITextView。

let tapGesture = UITapGestureRecognizer(target: self, action: #selector(textTapped))
tapGesture.numberOfTapsRequired = 1
myTextView.addGestureRecognizer(tapGesture)

从技术上讲，它recognizer.view是一个可选类型（UIView!），可以是nil，但是似乎textTapped()没有将您命名为未设置的类型。同样，layoutManager类型为NSLayoutManager!。为了安全起见，Swift的方法是：

guard let textView = recognizer.view as? UITextView, let layoutManager = textView.layoutManager else {
    return
}
// code using textView and layoutManager goes here

实际上，如果您以此方式编写，就不会崩溃，因为UIViewto 的条件强制转换UITextView不会成功。

为了使所有这些工作正常，请将属性添加到您将在textTapped例程中提取的属性字符串中：

var beginning = NSMutableAttributedString(string: "To the north you see a ")
var attrs = [NSFontAttributeName: UIFont.systemFontOfSize(19.0), "idnum": "1", "desc": "old building"]
var condemned = NSMutableAttributedString(string: "condemned building", attributes: attrs)
beginning.appendAttributedString(condemned)
attrs = [NSFontAttributeName: UIFont.systemFontOfSize(19.0), "idnum": "2", "desc": "lake"]
var lake = NSMutableAttributedString(string: " on a small lake", attributes: attrs)
beginning.appendAttributedString(lake)
myTextView.attributedText = beginning

这是完整的textTapped：

@objc func textTapped(recognizer: UITapGestureRecognizer) {
    guard let textView = recognizer.view as? UITextView, let layoutManager = textView.layoutManager else {
        return
    }
    var location: CGPoint = recognizer.locationInView(textView)
    location.x -= textView.textContainerInset.left
    location.y -= textView.textContainerInset.top

    /* 
    Here is what the Documentation looks like :

    Returns the index of the character falling under the given point,    
    expressed in the given container's coordinate system.  
    If no character is under the point, the nearest character is returned, 
    where nearest is defined according to the requirements of selection by touch or mouse.  
    This is not simply equivalent to taking the result of the corresponding 
    glyph index method and converting it to a character index, because in some 
    cases a single glyph represents more than one selectable character, for example an fi ligature glyph.
    In that case, there will be an insertion point within the glyph, 
    and this method will return one character or the other, depending on whether the specified 
    point lies to the left or the right of that insertion point.  
    In general, this method will return only character indexes for which there 
    is an insertion point (see next method).  The partial fraction is a fraction of the distance 
    from the insertion point logically before the given character to the next one, 
    which may be either to the right or to the left depending on directionality.
    */
    var charIndex = layoutManager.characterIndexForPoint(location, inTextContainer: textView.textContainer, fractionOfDistanceBetweenInsertionPoints: nil)

    guard charIndex < textView.textStorage.length else {
        return
    }

    var range = NSRange(location: 0, length: 0)
    if let idval = textView.attributedText?.attribute("idnum", atIndex: charIndex, effectiveRange: &range) as? NSString {
        print("id value: \(idval)")
        print("charIndex: \(charIndex)")
        print("range.location = \(range.location)")
        print("range.length = \(range.length)")
        let tappedPhrase = (textView.attributedText.string as NSString).substringWithRange(range)
        print("tapped phrase: \(tappedPhrase)")
        var mutableText = textView.attributedText.mutableCopy() as NSMutableAttributedString
        mutableText.addAttributes([NSForegroundColorAttributeName: UIColor.redColor()], range: range)
        textView.attributedText = mutableText
    }
    if let desc = textView.attributedText?.attribute("desc", atIndex: charIndex, effectiveRange: &range) as? NSString {
        print("desc: \(desc)")
    }
}