Resizing UILabel to fit text

Posted on July 10, 2009 by Jonah Williams

UILabels are often the most convenient way to display simple text in an iPhone app however I often want a label to display variable text which may need to wrap to multiple lines. Simply increasing the height of the UILabel doesn’t help because a single line of text will be centered vertically within the label’s bounds. Instead I need to computer the size of the text I want to render and update the label’s frame’s height accordingly.

In most cases I want to adjust the size of not only a label but the view containing that label as well so I wrote a category to resize labels and their parent views.

@interface UIView (Resize)

- (CGFloat) resizeLabel:(UILabel *)theLabel;

- (CGFloat) resizeLabel:(UILabel *)theLabel shrinkViewIfLabelShrinks:(BOOL)canShrink;

@end

@implementation UIView (Resize)

- (CGFloat) resizeLabel:(UILabel *)theLabel shrinkViewIfLabelShrinks:(BOOL)canShrink {
    CGRect frame = [theLabel frame];
    CGSize size = [theLabel.text sizeWithFont:theLabel.font
    constrainedToSize:CGSizeMake(frame.size.width, 9999)
    lineBreakMode:UILineBreakModeWordWrap];
    CGFloat delta = size.height - frame.size.height;
    frame.size.height = size.height;
    [theLabel setFrame:frame];

    CGRect contentFrame = self.frame;
    contentFrame.size.height = contentFrame.size.height + delta;
    if(canShrink || delta > 0) {
        [self setFrame:contentFrame];
    }
    return delta;
}

- (CGFloat) resizeLabel:(UILabel *)theLabel {
    return [self resizeLabel:theLabel shrinkViewIfLabelShrinks:YES];
}

@end

Now my labels can always fit their text.

This sort of programmatic resizing can become a little bit tricky when it displaces other sub-views of the label’s parent view. For example a view containing three re-sizable labels would need additional logic to maintain the vertical spacing between them.

http://svn.carbonfive.com/public/jonah/ResizableLabelExample

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  • Sellib

    Thanks for the post. Will be a great help.

  • Jessica

    Thanks, this was exactly what I was looking for!

  • Gal

    Thanks man!
    Helped a lot!!!

  • http://twitter.com/slashCJ C.J. Windisch

    Works great – one gotcha to look out for is to make sure of is that your UILabel’s numberOfLines setting is greater than the number of lines you’re resizing for, otherwise the box will resize but the text will truncate after that number of lines.

  • Grododo

    Thanks a lot, it’s just what I’m looking for =)

  • Rich

    Nice, thanks for sharing :)

  • http://www.candytunes.com/ jord3t

    for a scroll pane:

    - (CGFloat) resizeLabel:(UILabel *)theLabel shrinkViewIfLabelShrinks:(BOOL)canShrink {
    CGRect frame = [theLabel frame];
    CGSize size = [theLabel.text sizeWithFont:theLabel.font
    constrainedToSize:CGSizeMake(frame.size.width, 9999)
    lineBreakMode:UILineBreakModeWordWrap];
    CGFloat delta = size.height – frame.size.height;
    frame.size.height = size.height;
    [theLabel setFrame:frame];

    myScrollView.contentSize = theLabel.frame.size;
    myScrollView.frame = CGRectMake(myScrollView.frame.origin.x, myScrollView.frame.origin.y, myScrollView.frame.size.width, myScrollView.frame.size.height);
    return delta;
    }

    - (CGFloat) resizeLabel:(UILabel *)theLabel {
    return [self resizeLabel:theLabel shrinkViewIfLabelShrinks:YES];
    }