ios - NSTextStorage 语法 Markdown

Question

我正在为 iOS/osx 编写语法 Markdown 。

它是 NSTextStorage 的子类。它在 iOS 中运行良好，但在 OSX 中(将代码 UIColor 转换为 NSColor 并将 UIFont 转换为 NSFont 后)它确实运行良好。如果我在当前行的末尾书写，效果很好，但如果我将插入符号位置更改为文本中间，在键入 1 个字母后，它会将插入符号位置更改为行尾。这只发生在 OSX 中，因为在 IOS 中它运行良好。

我知道问题出在 - (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range 但不知道如何解决...有什么帮助吗？

- (NSString *)string {
    return [_backingStore string];
}

- (NSDictionary *)attributesAtIndex:(NSUInteger)location effectiveRange:(NSRangePointer)range {
    return [_backingStore attributesAtIndex:location effectiveRange:range];
}

- (void)replaceCharactersInRange:(NSRange)range withString:(NSString*)str {

    [self beginEditing];
    [_backingStore replaceCharactersInRange:range withString:str];
    [self edited:NSTextStorageEditedCharacters | NSTextStorageEditedAttributes range:range changeInLength:str.length - range.length];
    [self endEditing];

}

- (void)setAttributes:(NSDictionary *)attrs range:(NSRange)range {

    [self beginEditing];
    [_backingStore setAttributes:attrs range:range];
    [self edited:NSTextStorageEditedAttributes range:range changeInLength:0];
    [self endEditing];

}

- (void)processEditing {

    [self performReplacementsForRange:[self editedRange]];
    [super processEditing];
}

- (void)performReplacementsForRange:(NSRange)changedRange {

    NSString* backingString = [_backingStore string];
    NSRange extendedRange = extendedRange = NSUnionRange(changedRange, [backingString lineRangeForRange:NSMakeRange(NSMaxRange(changedRange), 0)]);
    [self applyStylesToRange:extendedRange];
}

- (void)applyStylesToRange:(NSRange)searchRange {

    NSDictionary* attributeDictionary = self.attributeDictionary;
    NSString* backingString = [_backingStore string];
    NSDictionary* bodyAttributes  = self.bodyAttributes;
    [self setAttributes:bodyAttributes range:searchRange];
    [attributeDictionary enumerateKeysAndObjectsUsingBlock:^(NSRegularExpression* regex, NSDictionary* attributes, BOOL* stop) {
        [regex enumerateMatchesInString:backingString options:0 range:searchRange
                             usingBlock:^(NSTextCheckingResult *match, NSMatchingFlags flags, BOOL *stop) {
                                 NSRange matchRange = [match rangeAtIndex:1];
                                 [self addAttributes:attributes range:matchRange];
                             }];
    }];

}

Answer 1

我不熟悉 NSTextStorage，但我设法通过覆盖 fixAttributesInRange: 而不是 processEditing 来解决这个问题。

代替

- (void)processEditing {

    [self performReplacementsForRange:[self editedRange]];
    [super processEditing];
}

做

- (void)fixAttributesInRange:(NSRange)range {
    [self performReplacementsForRange:range];
    [super fixAttributesInRange:(NSRange)range];
}

顺便说一句:applyStylesToRange 不应该嵌套在 beginEditing 和 endEditing 之间吗？