About AttributeString - making multiple occurrences bold

Question

I am trying to make multiple occurrences in a attributed string bold using something like the following

[attrStr setFont:[UIFont ...] range:[attrStr.string rangeOfString:@"hello world"]];

As you know, 'rangeOfString' always return the FIRST occurrence of the match... I am still quite new to iOS, just wondering what's the best way to set all occurrences to bold... Is there any function provided in NSString or something?

Thanks in advance!

Answer 1

You should first try to get all ranges in the string and then set the attribute for every range. There are some great code examples right here on stackoverflow: https://stackoverflow.com/a/4653266/381870

Edit:

Here's an example for you

- (NSArray *)rangesOfString:(NSString *)searchString inString:(NSString *)str {
    NSMutableArray *results = [NSMutableArray array];
    NSRange searchRange = NSMakeRange(0, [str length]);
    NSRange range;
    while ((range = [str rangeOfString:searchString options:0 range:searchRange]).location != NSNotFound) {
        [results addObject:[NSValue valueWithRange:range]];
        searchRange = NSMakeRange(NSMaxRange(range), [str length] - NSMaxRange(range));
    }
    return results;
}

Usage:

NSArray *results = [self rangesOfString:@"foo" inString:@"foo bar foo"];
NSLog(@"%@", results);

gives you

(
    "NSRange: {0, 3}",
    "NSRange: {8, 3}"
)

Answer 2

Converting Tim's answer to Swift 4:

extension NSString {
    open func ranges(of searchString: String) -> [NSRange] {
        var ranges = [NSRange]()
        var searchRange = NSRange(location: 0, length: self.length)
        var range: NSRange = self.range(of: searchString)
        while range.location != NSNotFound {
            ranges.append(range)
            searchRange = NSRange(location: NSMaxRange(range), length: self.length - NSMaxRange(range))
            range = self.range(of: searchString, options: [], range: searchRange)
        }
        return ranges
    }
}

Also did it to Swift's String primitive:

extension String {
    func ranges(of substring: String, options: CompareOptions = [], locale: Locale? = nil) -> [Range<Index>] {
        var ranges: [Range<Index>] = []
        while let range = self.range(of: substring, options: options, range: (ranges.last?.upperBound ?? self.startIndex)..<self.endIndex, locale: locale) {
            ranges.append(range)
        }
        return ranges
    }
}