Question

我有UITextView，当用户在其中输入文字时，我想动态格式化文本。语法突出显示......

为此，我想使用UITextView ...

一切正常，期待一个问题：我从文本视图中获取文本并从中创建NSAttributedString。我对此属性字符串进行了一些编辑，并将其设置为textView.attributedText。

每次用户输入时都会发生这种情况。所以我必须在编辑selectedTextRange之前记住attributedText并在之后重新设置它，以便用户可以继续在他之前输入的地方打字。唯一的问题是，一旦文本足够长，需要滚动，UITextView现在将开始滚动到顶部，如果我慢慢输入。

以下是一些示例代码：

- (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;
}

有没有直接使用CoreText的解决方案？我喜欢UITextView选择文字等的能力....

Answer 1

我不确定这是正确的解决方案，但它确实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;
}

Answer 2

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
}

Answer 3

Swift 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

Answer 4

在Swift 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
}

用属性字符串替换UITextViews文本

4 个答案: