ios - 使 TextView 响应用户键入的文本

Question

我的应用程序中有一个 TextView ，允许用户在其中键入任何内容。我希望 TextView 在输入时检测到一些单词并改变它们的颜色。

例如，如果用户键入“我最喜欢的颜色是红色”，那么我希望单词“红色”获得文本颜色“红色”。但是，thus 应该在句子中输入 red 之后立即发生。我应该如何实现？

Answer 1

你需要三样东西:

• 在界面生成器中，您需要使用其中一种委托(delegate)方法。我认为“editingChanged”是这里最好的。使用“ctrl”从文本字段拖动到您的文档。

• 您需要一种方法来遍历文本字段中的字符串并检测单词。

  componentsSeparatedByCharactersInSet

• 您需要一种方法来为句子中的一个词设置样式。

  NSMutableAttributedString

也很有趣:how to separate a string without removing the delimiter

部分代码(扔在 Playground 上):

这将找到所有要更改的单词，但会删除分隔符。需要做更多工作才能完成代码。

var strSeperator : NSCharacterSet = NSCharacterSet(charactersInString: ",.:;?! ")

var strArray = str.componentsSeparatedByCharactersInSet(strSeperator)

var styledText = NSMutableAttributedString()

for i in 0..<strArray.count {

    let currentWord = strArray[i]
    var currentBoolFoundInControl : Bool = false

    for iB in 0..<colorTheseStrings.count {

        let controlWord = colorTheseStrings[iB]

        if controlWord == currentWord {
            currentBoolFoundInControl = true
            // add to mutable attributed string in a color
        }

    }

    var attrString1 = NSMutableAttributedString(string: "\(strArray[i]) ")

    if currentBoolFoundInControl == true {

        var range = (strArray[i] as NSString).rangeOfString(strArray[i])
        if strArray[i] == "red" {
            attrString1.addAttribute(NSForegroundColorAttributeName, value: UIColor(red: 0.5, green: 0.0, blue: 0.0, alpha: 1.0), range: range)
        } else if strArray[i] == "blue" {
            attrString1.addAttribute(NSForegroundColorAttributeName, value: UIColor(red: 0.0, green: 0.0, blue: 0.5, alpha: 1.0), range: range)

        }
    }

    styledText.appendAttributedString(attrString1)
}

myTextField.attributedText = styledText

另一种方式:

download it here

我觉得这种方式是最稳健最酷最高效的。 代码可以稍微清理一下，可以使用更多的风格/风格。这对于“天蓝色”之类的东西确实有麻烦，因为它会首先找到“蓝色”并替换它。但我不得不留下一些改进的余地。 ;)

我情不自禁，所以我解决了最后一个问题。

再一次，我修复了，我的修复。现在更有效率并且实际上是正确的。

第一部分是 HighLighter 类，将其放在单独的文档中。

// text hightlighter

class SyntaxGroup {

    var wordCollection : [String] = []
    var type : String = ""
    var color : UIColor = UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)

    init(wordCollection_I : [String], type_I : String, color_I: UIColor) {

        wordCollection = wordCollection_I
        type = type_I
        color = color_I

    }
}

class SyntaxDictionairy {

    var collections : [SyntaxGroup] = []

}

class SyntaxRange {

    var range : NSRange
    var color : UIColor

    init (color_I : UIColor, range_I : NSRange) {
        color = color_I
        range = range_I
    }

}

class HighLighter {

    var ranges : [SyntaxRange] = []
    var baseString : NSMutableString = NSMutableString()
    var highlightedString : NSMutableAttributedString = NSMutableAttributedString()
    var syntaxDictionairy : SyntaxDictionairy

    init (syntaxDictionairy_I : SyntaxDictionairy) {

        syntaxDictionairy = syntaxDictionairy_I

    }

    func run(string : String?, completion: (finished: Bool) -> Void) {

        ranges = [] // reset the ranges, else it crashes when you change a previous part of the text
        highlightedString = NSMutableAttributedString() // make sure all strings start fresh
        baseString = NSMutableString() // make sure all strings start fresh

        // multi threading to prevent locking up the interface with large libraries.
        let qualityOfServiceClass = QOS_CLASS_DEFAULT
        let backgroundQueue = dispatch_get_global_queue(qualityOfServiceClass, 0)
        dispatch_async(backgroundQueue) { () -> Void in

            if string != nil && string != "" {

                self.highlightedString = NSMutableAttributedString(string: string!)

                for i in 0..<self.syntaxDictionairy.collections.count {

                    for iB in 0..<self.syntaxDictionairy.collections[i].wordCollection.count {

                        let currentWordToCheck = self.syntaxDictionairy.collections[i].wordCollection[iB]
                        self.baseString = NSMutableString(string: string!)

                        while self.baseString.containsString(self.syntaxDictionairy.collections[i].wordCollection[iB]) {

                            let nsRange = (self.baseString as NSString).rangeOfString(currentWordToCheck)
                            let newSyntaxRange = SyntaxRange(color_I: self.syntaxDictionairy.collections[i].color, range_I: nsRange)
                            self.ranges.append(newSyntaxRange)

                            var replaceString = ""
                            for _ in 0..<nsRange.length {
                                replaceString += "§" // secret unallowed character
                            }
                            self.baseString.replaceCharactersInRange(nsRange, withString: replaceString)
                        }
                    }
                }
                for i in 0..<self.ranges.count {

                    self.highlightedString.addAttribute(NSForegroundColorAttributeName, value: self.ranges[i].color, range: self.ranges[i].range)

                }
            }

            dispatch_sync(dispatch_get_main_queue()) { () -> Void in

                completion(finished: true)
            }

        }
    }
}

在 View Controller 中: 这是您将与 UITextfield 一起使用的代码。 首先创建一个荧光笔实例并设置你的单词字典和相应的颜色。然后在需要的时候启动run函数。

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var myTextfield: UITextField!

    var syntaxHighLighter : HighLighter! // declare highlighter

    override func viewDidLoad() {
        super.viewDidLoad()
        setUpHighLighter()
    }
    // this is just a little function to put the set up for the highlighter outside of viewDidLoad()
    func setUpHighLighter() {

        // build a dict of words to highlight
        let redColor = UIColor(red: 0.5, green: 0.0, blue: 0.0, alpha: 1.0)
        let blueColor = UIColor(red: 0.0, green: 0.0, blue: 0.5, alpha: 1.0)
        let greenColor = UIColor(red: 0.0, green: 0.5, blue: 0.0, alpha: 1.0)

        let redGroup = SyntaxGroup(wordCollection_I: ["red","bordeaux"], type_I: "Color", color_I: redColor)
        let blueGroup = SyntaxGroup(wordCollection_I: ["coralblue","blue","skyblue","azur"], type_I: "Color", color_I: blueColor)
        let greenGroup = SyntaxGroup(wordCollection_I: ["green"], type_I: "Color", color_I: greenColor)

        let dictionairy : SyntaxDictionairy = SyntaxDictionairy()
        dictionairy.collections.append(blueGroup)
        dictionairy.collections.append(greenGroup)
        dictionairy.collections.append(redGroup)

        syntaxHighLighter = HighLighter(syntaxDictionairy_I: dictionairy)

    }
    // this is where the magic happens, place the code from inside the editingChanged inside your function that responds to text changes.
    @IBAction func editingChanged(sender: UITextField) {

        syntaxHighLighter.run(myTextfield.text) { (finished) -> Void in
            self.myTextfield.attributedText = self.syntaxHighLighter.highlightedString
        }
    }
}