如何获取从 -textStorageDidProcessEditing: 中可见的字符范围? [英] How to get the range of characters that are visible from within -textStorageDidProcessEditing:?

问题描述

对于我的语法高亮实现，我使用 -[<NSTextStorageDelegate> 观察了 NSTextView 的变化.textStorageDidProcessEditing:].

For my syntax highlighting implementation, I observe changes to an NSTextView using -[<NSTextStorageDelegate> textStorageDidProcessEditing:].

- (void)textStorageDidProcessEditing:(NSNotification *)notification {
  if (!self.languageGrammar) return;
  NSTextStorage *textStorage = self.textView.textStorage;
  NSRange glyphRange = [self.textView.layoutManager glyphRangeForBoundingRect:self.scrollView.documentVisibleRect
                                                              inTextContainer:self.textView.textContainer];
  NSRange editedRange = [self.textView.layoutManager characterRangeForGlyphRange:glyphRange actualGlyphRange:NULL];

  [textStorage removeAttribute:NSForegroundColorAttributeName range:editedRange];
  // crash is the line above ^^^^
  // color text ...
}

我想获取可见字符的范围.上面的代码一直有效，直到我点击 backspace，这让它崩溃了:

I want to get the range of visible characters. The above code works until I hit backspace, which makes it crash:

*** -[NSConcreteTextStorage attributesAtIndex:effectiveRange:]: Range or index out of bounds

如何获取可见字符的范围以便为它们着色?

How would I get the range of visible characters so I can color them?

推荐答案

检查范围是否超出了整个字符串的边界，如果设置的范围适合字符串的边界:

Check if the range is beyond the bounds of the entire string, and if it is set the range to fit the bounds of the string:

NSRange range = NSRangeFromString(string);

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