Set UILabel's number of lines depending by the text contained - Objective C and/or Swift

Question

I'm trying to display some random text into a UILabel and of course I have nothing but its width. Is there a way to set my UILabel's height and/or number of lines depending by the text contained in it?

Thanks ;)

Answer 1

myUILabel.numberOfLines = 0;
myUILabel.text = @"Pass random text here";
[myUILabel sizeToFit];

Answer 2

For Swift 4.0

func getStringHeight(mytext: String, fontSize: CGFloat, width: CGFloat)->CGFloat {

    let font = UIFont.systemFont(ofSize: fontSize)
    let size = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.lineBreakMode = .byWordWrapping;
    let attributes = [NSAttributedStringKey.font:font,
                      NSAttributedStringKey.paragraphStyle:paragraphStyle.copy()]

    let text = mytext as NSString
    let rect = text.boundingRect(with: size,
                                options:.usesLineFragmentOrigin,
                                attributes: attributes,
                                context:nil)
    return rect.size.height
}

Answer 3

Or (if you need the height of the label for a specific width and font size, you could calculate it with this):

func getStringHeight(mytext: String, fontSize: CGFloat, width: CGFloat)->CGFloat {

    let font = UIFont.systemFontOfSize(fontSize)
    let size = CGSizeMake(width,CGFloat.max)
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.lineBreakMode = .ByWordWrapping;
    let attributes = [NSFontAttributeName:font,
        NSParagraphStyleAttributeName:paragraphStyle.copy()]

    let text = mytext as NSString
    let rect = text.boundingRectWithSize(size, options:.UsesLineFragmentOrigin, attributes: attributes, context:nil)
    return rect.size.height  
}

You need this for Swift or for Objective C?

Answer 4

You can use NSString UIKIT Addition method

- (CGSize)sizeWithFont:(UIFont *)font
     constrainedToSize:(CGSize)size
         lineBreakMode:(NSLineBreakMode)lineBreakMode

to calculate the hight. something like.

CGSize yourLabelSize = [@"Your very long text" sizeWithFont:yourFont constrainedToSize:CGSizeMake(desiredMaximumWidth, 2000) lineBreakMode:NSLineBreakByWordWrapping];

its really important to understand the constrainedToSize parameter. You have to pass a CGSize with desired maximum width and maximum possible height. Use the same UIFont with your label. Dont forget to set the

[yourLabel setNumberOfLines:0];

But the method is already deprecated in iOS 7 therefore you have to use

- (CGRect)boundingRectWithSize:(CGSize)size
                       options:(NSStringDrawingOptions)options
                    attributes:(NSDictionary *)attributes
                       context:(NSStringDrawingContext *)context

yourLabelSize.height will give you the height

hope it will help you...