如何获取从-textStorageDidProcessEditing：？内可见的字符范围 [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，我观察到 NSTextView 使用 - [< NSTextStorageDelegate> 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。上述代码工作，直到我点击 backspace ，这会导致崩溃：

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

推荐答案

检查范围是否超出整个字符串的边界，如果设置了适合字符串边界的范围：

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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