How to change a text color for a certain attributed string or make it bold?

Question

Say I have NSString * hello = @"hello world";

Now I want an atributed string where the hell in hello world is bolded.

There is a function on the web that do this:

- (NSMutableAttributedString*) word:(NSString*)substringToHighlight{

    NSMutableAttributedString * mutableAttributedString = [[ NSMutableAttributedString alloc]initWithString:self];
    NSUInteger count = 0, length = [mutableAttributedString length];
    NSRange range = NSMakeRange(0, length);

    count = 0,
    length = [mutableAttributedString length];
    range = NSMakeRange(0, length);
    while(range.location != NSNotFound)
    {
        range = [[mutableAttributedString string] rangeOfString:substringToHighlight options:0 range:range];
        if(range.location != NSNotFound) {

            //[mutableAttributedString setTextColor:[UIColor blueColor] range:NSMakeRange(range.location, [word length])];
            range = NSMakeRange(range.location + range.length, length - (range.location + range.length));
            count++;
        }
    }
    return mutableAttributedString;
}

However, the function doesn't work because mutableAttributedString doestn't support setTextColor

I also tried

NSDictionary * dict = @{kCTFontAttributeName:boldFontName};
        [mutableAttributedString setAttributes:{kCTFontAttributeName:boldFontName} range:NSMakeRange(range.location, substringToHighlight.length)];

but got a message kCTFontAttributeName is not defined.

Answer 1

You can use rangeOfString:options:range: or NSScanner (there are other possibilities like regexps but anyway).

Finds and returns the range of the first occurrence of a given string, within the given range of the receiver, subject to given options.

• (NSRange)rangeOfString:(NSString *)aString options:(NSStringCompareOptions)mask range:(NSRange)aRange

This is another solution :

Then you need to convert into NSMutableAttributedString like this way.

NSMutableAttributedString *string = [[NSMutableAttributedString alloc] initWithString:@"hello world"];
NSRange selectedRange = NSMakeRange(0, 4); // 4 characters, starting at index 0

[string beginEditing];

[string addAttribute:NSFontAttributeName
           value:[NSFont fontWithName:@"Helvetica-Bold" size:12.0]
           range:selectedRange];

[string endEditing];

I think this is the best solution.