NSForegroundColorAttributeName not working for UILabel

W

3

7

I have a problem changing substring color using "NSForegroundColorAttributeName". I'm confused since other attributes for the same substring are being applied(underline).

Also tried to use deprecated attribute "UITextAttributeTextColor" and other suggested attribute "kCTForegroundColorAttributeName" and got the same effect.

I'm compiling for iOS 7.

enter image description here

    NSString *freeText = [NSString stringWithFormat:@"(%@)", self.me.activity.text];

    int lblMaxWidth = arrImgView.origin.x - WPRConstraints.BorderOffset;
    int lblMaxHeight = self.activityView.size.height - WPRConstraints.BorderOffset * 2;

    RevUILabel *addActivityLbl = [[RevUILabel alloc] initWithFontNameMultiLine:[WPRFonts LattoBold]
                                                                          size:16
                                                                 sizeConstrain:CGSizeMake(lblMaxWidth,lblMaxHeight)];

    addActivityLbl.text = [NSString stringWithFormat:@"%@ %@", Translate(self.me.activity.activityKey), freeText] ;
    addActivityLbl.textColor = BlackColor;

    NSMutableAttributedString *str = [addActivityLbl.attributedText mutableCopy];



    [str addAttribute:NSUnderlineColorAttributeName  value:[UIColor redColor] range:[addActivityLbl.text rangeOfString:freeText]];
    [str addAttribute:NSUnderlineStyleAttributeName  value:[NSNumber numberWithInteger:1] range:[addActivityLbl.text rangeOfString:freeText]];

    [str addAttribute:NSForegroundColorAttributeName
                        value:[UIColor redColor]
                range:[addActivityLbl.text rangeOfString:freeText]];


    addActivityLbl.attributedText = str;


    addActivityLbl.frame = CGRectMake(WPRConstraints.BorderOffset,
                                      WPRConstraints.BorderOffset,
                                      addActivityLbl.size.width,
                                      addActivityLbl.size.height);
    [self.activityView addSubview:addActivityLbl];

Wheaton answered 15/2, 2015 at 8:59 Comment(6)

Have you tried to pass a CGColor instead UIColor? – Wheeling 15/2, 2015 at 9:9

Yes I did with kCTForegroundColorAttributeName attribute – Wheaton 15/2, 2015 at 9:15

Sorry again, could comment the other attributes and update me with the results? – Wheeling 15/2, 2015 at 9:23

Please look in to the code I posted and the screenshot. – Wheaton 15/2, 2015 at 9:32

Does that label changes the text color elsewhere? – Wheeling 15/2, 2015 at 11:11

The only place is in code I posted before applying attributes – Wheaton 15/2, 2015 at 11:31

A

8

The problem is this line:
NSMutableAttributedString *str = [addActivityLbl.attributedText mutableCopy];

I don't know the previous lines of your code, but it might be the case that addActivityLbl.attributedText is empty.

Secondly, using NSAttributedString with UILabel is not as reliable as using it with UITextView. The attributedText of a UILabel does inherit the attributes from the text of UILabel if the attributes are not explicitly provided.

Your addActivityLbl.textColor is black. And you still have not set your addActivityLbl.attributedText ForegroundColorAttribute. This means that your addActivityLbl.attributedText will inherit the BlackColor from your addActivityLbl.textColor.

This line will not work as expected; because you still have not set your addActivityLbl.attributedText. freeText has no range yet.

[str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:[addActivityLbl.text rangeOfString:freeText]];

The underlyning works because underlyning is not a property of addActivityLbl.text (not inherited by attributedText).

I recommend you to use UITextView instead (which is safer). An other option is to set your label.attributedText, before referencing to some range of it.

Anguine answered 15/2, 2015 at 12:20 Comment(4)

I've tried to set attributed text before anything else and got very strange behaviour - dots instead of letters. Anyway, the only thing that works for me as expected is using UITextView instead of UILabel. I'm not that happy to use this workaround since I still do not understand root case of the problem. If I won't figure it out during next few days, I'll accept this answer. – Wheaton 15/2, 2015 at 12:58

I don't know what RevUILabel is. I googled it and couldn't find anything (but a 2 SO questions). Is it a subclass of UIView? – Anguine 15/2, 2015 at 13:1

No. It is just UILabel extention – Wheaton 15/2, 2015 at 13:2

Using UITextView is the only solution I found so far. – Wheaton 1/6, 2015 at 14:32

A

11

Make sure you're not setting some color on textColor property of UILabel after you've set the attributedText.

Adrianaadriane answered 28/9, 2016 at 13:55 Comment(0)