ios - 如何在 Swift3 中更改 UITextView 中文本字符串的颜色

Question

我在这里查看了一些现有的问题帖子，并尝试实现所有代码，但最终无法成功实现任何代码。实际上，我想我理解了如何更改 UITextView 中某些文本的颜色。如果最初设置了文本，但我不明白的是，当我的 UITextView开始进入编辑，它似乎根本无法正常工作。在下文中，我尝试的代码完全满足了我想要的行为。

 func textViewDidBeginEditing(_ textView: UITextView) {

    let main_string = ""
    let getData: [String] = userDefaults.object(forKey: "myData") as! [String]
    print("\(getData)")

    let searchWords = "world"

        let range = (main_string as NSString).range(of: searchWords)

        let attribute = NSMutableAttributedString.init(string: main_string)
        attribute.addAttribute(NSForegroundColorAttributeName, value: UIColor.red , range: range)

        mytextView.attributedText = attribute


}

我通过命名 MyData 保存了输入数据.我尝试使用 for 循环从 getData 中取出所有元素并将其用作个人值(value)。但是，在控制台中，解释的行数太多了。我认为这是一种正确的写作方式，但我的 mac 说 nooooooo。但是，如果我设置 String里面 main_string和 searchWords ，例如，main_string 中的“这是我的问题。我希望人们从世界上帮助我”和 searchWords 中的“world”，如代码中所写。然后在加载应用程序后，在我的 TextView 中，“世界”这个词完美地以红色突出显示，但在世界词之后，所有文本都是红色的。我不明白为什么我会被这个未知的错误折磨。

所以我想要完成的是

从我的 myData 中保存的日期开始，我只希望在用户输入时及时突出显示存储的单词。例如，如果用户输入“hello”和“world”。然后他们被 myData 保存。并且它们只会在键入时突出显示。并在键入未存储的单词时切换回正常颜色。

我想我缺乏一些解释。如果你需要知道什么，请指出我。非常感谢!!

Answer 1

在此，我以字符串“world”为例。当您在 textview 中输入时，此方法有效

func textViewDidChange(_ textView: UITextView) {
        let attrStr = NSMutableAttributedString(string:txtview.text)
        let inputLength = attrStr.string.characters.count
        let searchString = "world"
        let searchLength = searchString.characters.count
        var range = NSRange(location: 0, length: attrStr.length)

        while (range.location != NSNotFound) {
            range = (attrStr.string as NSString).range(of: searchString, options: [], range: range)
            if (range.location != NSNotFound) {
                attrStr.addAttribute(NSForegroundColorAttributeName, value: UIColor.red, range: NSRange(location: range.location, length: searchLength))
                range = NSRange(location: range.location + range.length, length: inputLength - (range.location + range.length))
                textView.attributedText = attrStr
            }
        }    
}

但是当您已经设置了 textview 的初始文本时，请使用此方法

func textViewDidBeginEditing(_ textView: UITextView) {
        //Just set your text as you set in textview
        let attrStr = NSMutableAttributedString(string: "hello world I ma jeckjklwefljlwjflkjwfkljelwfjklfgjwklfjlkwgjwlgkjwklsgjklsjgklsdjgkljdslkgjsdlkgjlksdjgldjsgldjskl world nsfhjklshfklhsllsd fgiw world")
        let inputLength = attrStr.string.characters.count
        let searchString = "world"
        let searchLength = searchString.characters.count
        var range = NSRange(location: 0, length: attrStr.length)

        while (range.location != NSNotFound) {
            range = (attrStr.string as NSString).range(of: searchString, options: [], range: range)
            if (range.location != NSNotFound) {
                attrStr.addAttribute(NSForegroundColorAttributeName, value: UIColor.red, range: NSRange(location: range.location, length: searchLength))
                range = NSRange(location: range.location + range.length, length: inputLength - (range.location + range.length))
                textView.attributedText = attrStr
            }
          }  
  }

对于多个字符串，您可以这样做 SWIFT 3

func textViewDidChange(_ textView: UITextView) {
        let attrStr = NSMutableAttributedString(string: txtview.text)
        let inputLength = attrStr.string.characters.count
        let searchString : NSArray = NSArray.init(objects: "hello","world")
        for i in 0...searchString.count-1
        {

             let string : String = searchString.object(at: i) as! String
             let searchLength = string.characters.count
             var range = NSRange(location: 0, length: attrStr.length)

             while (range.location != NSNotFound) {
                 range = (attrStr.string as NSString).range(of: string, options: [], range: range)
                 if (range.location != NSNotFound) {
                 attrStr.addAttribute(NSForegroundColorAttributeName, value: UIColor.red, range: NSRange(location: range.location, length: searchLength))
                 range = NSRange(location: range.location + range.length, length: inputLength - (range.location + range.length))
                 textView.attributedText = attrStr
        }
    }   
  }
}

objective-c
对于多个字符串，您可以这样做

-(void)textViewDidChange:(UITextView *)textView
{
    NSMutableAttributedString *attstr = [[NSMutableAttributedString alloc]initWithString:textView.text];
    NSUInteger characterCount = [attstr length];
    NSArray *arr = [[NSArray alloc]initWithObjects:@"football",@"player",nil];

    for (int i=0; i<arr.count; i++) {

    NSUInteger searchlength = [[NSString stringWithFormat:@"%@",[arr objectAtIndex:i]] length];
    NSRange range1 = NSMakeRange(0, attstr.length);

    while (range1.location != NSNotFound) {
        range1 =[attstr.string rangeOfString:[NSString stringWithFormat:@"%@",[arr objectAtIndex:i]] options:0 range:range1];
        if (range1.location !=NSNotFound) {
            [attstr addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(range1.location, searchlength)];
            [attstr addAttribute:NSFontAttributeName value:[UIFont systemFontOfSize:20.0]  range:range1];
            range1 = NSMakeRange(range1.location + range1.length, characterCount -(range1.location + range1.length));
            textView.attributedText = attstr;
        }
    }
}