how to change characters case to Upper in NSAttributedString

问题

I want to convert NSAttributedString containing RTFD to uppercase without losing attributes of existing characters and graphics.

Thanks,

回答1:

EDIT:

@fluidsonic Is correct that the original code is incorrect. Below is an updated version in Swift, that replaces the text in each attribute range with an uppercased version of the string in that range.

extension NSAttributedString {
    func uppercased() -> NSAttributedString {

        let result = NSMutableAttributedString(attributedString: self)

        result.enumerateAttributes(in: NSRange(location: 0, length: length), options: []) {_, range, _ in
            result.replaceCharacters(in: range, with: (string as NSString).substring(with: range).uppercased())
        }

        return result
    }
}

Original answer:

- (NSAttributedString *)upperCaseAttributedStringFromAttributedString:(NSAttributedString *)inAttrString {
    // Make a mutable copy of your input string
    NSMutableAttributedString *attrString = [inAttrString mutableCopy];

    // Make an array to save the attributes in
    NSMutableArray *attributes = [NSMutableArray array];

    // Add each set of attributes to the array in a dictionary containing the attributes and range
    [attrString enumerateAttributesInRange:NSMakeRange(0, [attrString length]) options:0 usingBlock:^(NSDictionary *attrs, NSRange range, BOOL *stop) {
        [attributes addObject:@{@"attrs":attrs, @"range":[NSValue valueWithRange:range]}];
    }];

    // Make a plain uppercase string
    NSString *string = [[attrString string]uppercaseString];

    // Replace the characters with the uppercase ones
    [attrString replaceCharactersInRange:NSMakeRange(0, [attrString length]) withString:string];

    // Reapply each attribute
    for (NSDictionary *attribute in attributes) {
        [attrString setAttributes:attribute[@"attrs"] range:[attribute[@"range"] rangeValue]];
    }

    return attrString;
}

What this does:

1. Makes a mutable copy of the input attributed string.
2. Takes all the attributes from that string and puts them in an array so they can be used later.
3. Makes an uppercase plain string using built-in NSString method.
4. Re-applys all the attributes.

来源：https://stackoverflow.com/questions/6716699/how-to-change-characters-case-to-upper-in-nsattributedstring