16

我有一个UITextView，当用户在其中输入文本时，我想即时格式化文本。语法高亮之类的东西...

为此，我想使用UITextView...

一切正常，但有一个问题：我从文本视图中获取文本并从中NSAttributedString提取。我对此属性字符串进行了一些编辑，并将其设置回textView.attributedText.

每次用户键入时都会发生这种情况。所以我必须记住selectedTextRange编辑之前的attributedText并在之后将其设置回来，以便用户可以在他之前输入的位置继续输入。唯一的问题是，一旦文本足够长需要滚动，UITextView如果我输入缓慢，现在将开始滚动到顶部。

这是一些示例代码：

- (void)formatTextInTextView:(UITextView *)textView
{
  NSRange selectedRange = textView.selectedRange;
  NSString *text = textView.text;

  // This will give me an attributedString with the base text-style
  NSMutableAttributedString *attributedString = [self attributedStringFromString:text];

  NSError *error = nil;
  NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"#(\\w+)" options:0 error:&error];
  NSArray *matches = [regex matchesInString:text
                                    options:0
                                      range:NSMakeRange(0, text.length)];

  for (NSTextCheckingResult *match in matches)
  {
    NSRange matchRange = [match rangeAtIndex:0];
    [attributedString addAttribute:NSForegroundColorAttributeName
                             value:[UIColor redColor]
                             range:matchRange];
  }

  textView.attributedText = attributedString;
  textView.selectedRange = selectedRange;
}

有没有不直接使用CoreText的解决方案？我喜欢UITextView选择文本的能力等等......

4

4 回答 4

40

我不确定这是正确的解决方案，但它有效。
只需在格式化文本之前禁用滚动并在格式化后启用它

- (void)formatTextInTextView:(UITextView *)textView
{
    textView.scrollEnabled = NO;
    NSRange selectedRange = textView.selectedRange;
    NSString *text = textView.text;

    // This will give me an attributedString with the base text-style
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:text];

    NSError *error = nil;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"#(\\w+)" options:0 error:&error];
    NSArray *matches = [regex matchesInString:text
                                      options:0
                                        range:NSMakeRange(0, text.length)];

    for (NSTextCheckingResult *match in matches)
    {
        NSRange matchRange = [match rangeAtIndex:0];
        [attributedString addAttribute:NSForegroundColorAttributeName
                                 value:[UIColor redColor]
                                 range:matchRange];
    }

    textView.attributedText = attributedString;
    textView.selectedRange = selectedRange;
    textView.scrollEnabled = YES;
}
于 2013-06-15T10:42:32.200 回答
4

我自己使用了 Sergeys 的答案并将其移植到 Swift 2：

func formatTextInTextView(textView: UITextView) {
    textView.scrollEnabled = false
    let selectedRange = textView.selectedRange
    let text = textView.text

    // This will give me an attributedString with the base text-style
    let attributedString = NSMutableAttributedString(string: text)

    let regex = try? NSRegularExpression(pattern: "#(\\w+)", options: [])
    let matches = regex!.matchesInString(text, options: [], range: NSMakeRange(0, text.characters.count))

    for match in matches {
        let matchRange = match.rangeAtIndex(0)
        attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: matchRange)
    }

    textView.attributedText = attributedString
    textView.selectedRange = selectedRange
    textView.scrollEnabled = true
}
于 2016-03-07T11:28:21.440 回答
1

在斯威夫特 4 中：

func createAttributedText() {
    let stringText = "Test String"
    let stringCount = stringText.count
    let string: NSMutableAttributedString = NSMutableAttributedString(string: stringText)

    string.addAttribute(NSForegroundColorAttributeName, value: UIColor.red, range: NSMakeRange(0, stringCount))

    self.textView.attributedText =  string
}
于 2018-08-12T14:09:09.570 回答
0

斯威夫特 2.0：

let myDisplayTxt:String = "Test String"

    let string: NSMutableAttributedString = NSMutableAttributedString(string: self.myDisplayTxt)
    string.addAttribute(NSForegroundColorAttributeName, value: UIColor.redColor(), range: NSMakeRange(0, 5))
    string.addAttribute(String(kCTForegroundColorAttributeName), value: UIColor.redColor().CGColor as AnyObject, range: NSMakeRange(0, 5))

    self.sampleTextView.attributedText =  string
于 2016-02-11T08:06:31.297 回答