如何实现自定义UITextInputTokenizer？

Question

我有一个UITextView，并且正在使用它的标记器来检查用户点击的单词。

我的目标是改变标记器所认为的单词。目前，它似乎将单词定义为连续字母数字字符，我希望将一个单词定义为不是空格字符(“")的连续字符。

例如：'foo-bar‘、'foo/bar’和'foo@@bar‘目前都将被视为两个单独的单词('foo’和'bar')，但我希望它们都被视为一个单词(因为它们中没有一个包含空格)。

文档讨论了对UITextInputStringTokenizer类进行子类化的问题，但是我找不到一个这样做的人的例子，我也不知道如何实现所需的方法：

func isPosition(position: UITextPosition, atBoundary granularity: UITextGranularity, inDirection direction: UITextDirection) -> Bool

func isPosition(position: UITextPosition, withinTextUnit granularity: UITextGranularity, inDirection direction: UITextDirection) -> Bool

func positionFromPosition(position: UITextPosition, toBoundary granularity: UITextGranularity, inDirection direction: UITextDirection) -> UITextPosition?

func rangeEnclosingPosition(position: UITextPosition, withGranularity granularity: UITextGranularity, inDirection direction: UITextDirection) -> UITextRange?

Answer 1

总之，创建扩展UITextInputStringTokenizer的实现，使大多数方法保持不变(或者只调用super)。

当粒度是word时，您只需要重写isPosition(_:atBoundary:inDirection:)和isPosition(_:withinTextUnit:inDirection:)，以检查该位置旁边的字符是否位于单词边界，即字母数字字符和空格一起。默认实现还将返回其他非空格的true，这些非空格被认为不是单词的一部分，相反，您可以将它们视为单词的一部分。当粒度不是word时，您也可以默认为super。

Answer 2

//创建UITextInputStringTokenizer类CustomTokenizer的子类: UITextInputStringTokenizer {

// Override the rangeEnclosingPosition method so that it looks for characters that are not a space (" ")
override func rangeEnclosingPosition(position: UITextPosition, withGranularity granularity: UITextGranularity, inDirection direction: UITextDirection) -> UITextRange? {
    // First check if the range enclosing the position is not nil
    guard let range = super.rangeEnclosingPosition(position: position, withGranularity: granularity, inDirection: direction) else {
        return nil
    }
    
    // Then define a string of characters that are not a space (" ")
    let nonSpaceCharacterSet = CharacterSet.init(charactersIn: "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLKMNOPQRSTUVWXYZ1234567890_")
    
    // Then define a range which will be used to search for the non space characters
    let startIndex = range.start
    let endIndex = range.end
    let searchRange = startIndex..<endIndex
    
    // Then define a string based on the range
    let text = self.textInput.text(in: searchRange)
    
    // Then search the string for any characters that are not a space (" ")
    if let _ = text?.rangeOfCharacter(from: nonSpaceCharacterSet) {
        // If any characters that are not a space (" ") are found, then return the range
        return range
    } else {
        // Otherwise, return nil
        return nil
    }
}

}

//然后将UITextView的令牌程序设置为CustomTokenizer textView.tokenizer = CustomTokenizer(textInput: textView)