Question

我知道这个问题已经在Objective-C中解决了，但我在Swift中没有看到任何解决方案。我试图从this帖子转换解决方案代码，但我收到了错误：

func textTapped(recognizer: UITapGestureRecognizer){

    var textView: UITextView = recognizer.view as UITextView
    var layoutManager: NSLayoutManager = textView.layoutManager
    var location: CGPoint = recognizer.locationInView(textView)
    location.x -= textView.textContainerInset.left
    location.y -= textView.textContainerInset.top

    var charIndex: Int
    charIndex = layoutManager.characterIndexForPoint(location, inTextContainer: textView.textContainer, fractionOfDistanceBetweenInsertionPoints: nil)

    if charIndex < textView.textStorage.length {
        // do the stuff
        println(charIndex)
    }
}

我认为问题出在这一行（见错误here）：

 var textView: UITextView = recognizer.view as UITextView

...我已根据此行从Objective-C转换而来：

 UITextView *textView = (UITextView *)recognizer.view;

最后，我也对如何调用此函数表示怀疑。据我了解，该函数应该传递给viewDidLoad（）中的Selector，如下所示：

 let aSelector: Selector = "textTapped:"   

 let tapGesture = UITapGestureRecognizer(target: self, action: aSelector)
 tapGesture.numberOfTapsRequired = 1
 view.addGestureRecognizer(tapGesture)

因为我收到了前面提到的错误，我不确定它是否会起作用。但我想我还需要将textTapped函数（识别器）中的参数传递给Selector。但是，我已经读过你只能传递函数而不是任何参数。

Answer 1

对于Swift 3.0或以上

将点击手势添加到UITextView

let tapGesture = UITapGestureRecognizer(target: self, action: #selector(tapOnTextView(_:)))
textView.addGestureRecognizer(tapGesture)

添加点按处理程序方法

@objc private final func tapOnTextView(_ tapGesture: UITapGestureRecognizer){

  let point = tapGesture.location(in: textView)
  if let detectedWord = getWordAtPosition(point)
  {

  }
}

从点上得到消息

private final func getWordAtPosition(_ point: CGPoint) -> String?{
if let textPosition = textView.closestPosition(to: point)
{
  if let range = textView.tokenizer.rangeEnclosingPosition(textPosition, with: .word, inDirection: 1)
  {
    return textView.text(in: range)
  }
}
return nil}

Answer 2

您需要将UITapGestureRecognizer添加到您想要点按的UITextView。您目前正在向UITapGestureRecognizer ViewController view添加UIView。这就是演员让你陷入困境的原因。您正在尝试将UITextView投射到let tapGesture = UITapGestureRecognizer(target: self, action: #selector(textTapped)) tapGesture.numberOfTapsRequired = 1 myTextView.addGestureRecognizer(tapGesture)。

recognizer.view

技术上UIView!是一种可选类型（nil），可能是textTapped()，但您的layoutManager似乎不太可能被称为NSLayoutManager!组。同样，guard let textView = recognizer.view as? UITextView, let layoutManager = textView.layoutManager else { return } // code using textView and layoutManager goes here的类型为UIView。但为了安全起见，Swift的方法是：

UITextView

事实上，如果你用这种方式编写，你就不会崩溃，因为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到textTapped的条件转换不会成功。

要完成所有工作，请将属性添加到您将在textTapped例程中提取的属性字符串中：

@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)")
    }
}

这里是完整的{{1}}：

{{1}}

从Swift中的UITextView中获取单词

2 个答案: