[ios] How to calculate UILabel width based on text length?

I want to display an image next to a UILabel, however UILabel has variable text length, so I don't know where to place the image. How can I accomplish this?

Here's something I came up with after applying a few principles other SO posts, including Aaron's link:

AnnotationPin *myAnnotation = (AnnotationPin *)annotation;

self = [super initWithAnnotation:myAnnotation reuseIdentifier:reuseIdentifier];
self.backgroundColor = [UIColor greenColor];
self.frame = CGRectMake(0,0,30,30);
imageView = [[UIImageView alloc] initWithImage:myAnnotation.THEIMAGE];
imageView.frame = CGRectMake(3,3,20,20);
imageView.layer.masksToBounds = NO;
[self addSubview:imageView];
[imageView release];

CGSize titleSize = [myAnnotation.THETEXT sizeWithFont:[UIFont systemFontOfSize:12]];
CGRect newFrame = self.frame;
newFrame.size.height = titleSize.height + 12;
newFrame.size.width = titleSize.width + 32;
self.frame = newFrame;
self.layer.borderColor = [UIColor colorWithRed:0 green:.3 blue:0 alpha:1.0f].CGColor;
self.layer.borderWidth = 3.0;
        
UILabel *infoLabel = [[UILabel alloc] initWithFrame:CGRectMake(26,5,newFrame.size.width-32,newFrame.size.height-12)];
infoLabel.text = myAnnotation.title;
infoLabel.backgroundColor = [UIColor clearColor];
infoLabel.textColor = [UIColor blackColor];
infoLabel.textAlignment = UITextAlignmentCenter;
infoLabel.font = [UIFont systemFontOfSize:12];

[self addSubview:infoLabel];
[infoLabel release];

In this example, I'm adding a custom pin to a MKAnnotation class that resizes a UILabel according to the text size. It also adds an image on the left side of the view, so you see some of the code managing the proper spacing to handle the image and padding.

The key is to use CGSize titleSize = [myAnnotation.THETEXT sizeWithFont:[UIFont systemFontOfSize:12]]; and then redefine the view's dimensions. You can apply this logic to any view.

Although Aaron's answer works for some, it didn't work for me. This is a far more detailed explanation that you should try immediately before going anywhere else if you want a more dynamic view with an image and resizable UILabel. I already did all the work for you!!

CGRect rect = label.frame;
rect.size = [label.text sizeWithAttributes:@{NSFontAttributeName : [UIFont fontWithName:label.font.fontName size:label.font.pointSize]}];
label.frame = rect;

In iOS8 sizeWithFont has been deprecated, please refer to

CGSize yourLabelSize = [yourLabel.text sizeWithAttributes:@{NSFontAttributeName : [UIFont fontWithName:yourLabel.font size:yourLabel.fontSize]}];

You can add all the attributes you want in sizeWithAttributes. Other attributes you can set:

- NSForegroundColorAttributeName
- NSParagraphStyleAttributeName
- NSBackgroundColorAttributeName
- NSShadowAttributeName

and so on. But probably you won't need the others

The selected answer is correct for iOS 6 and below.

In iOS 7, sizeWithFont:constrainedToSize:lineBreakMode: has been deprecated. It is now recommended you use boundingRectWithSize:options:attributes:context:.

CGRect expectedLabelSize = [yourString boundingRectWithSize:sizeOfRect
                                                    options:<NSStringDrawingOptions>
                                                 attributes:@{
                                                    NSFontAttributeName: yourString.font
                                                    AnyOtherAttributes: valuesForAttributes
                                                 }
                                                    context:(NSStringDrawingContext *)];

Note that the return value is a CGRect not a CGSize. Hopefully that'll be of some assistance to people using it in iOS 7.

yourLabel.intrinsicContentSize.width for Objective-C / Swift

In swift

 yourLabel.intrinsicContentSize().width 

Swift 4 Answer who are using Constraint

label.text = "Hello World"

var rect: CGRect = label.frame //get frame of label
rect.size = (label.text?.size(attributes: [NSFontAttributeName: UIFont(name: label.font.fontName , size: label.font.pointSize)!]))! //Calculate as per label font
labelWidth.constant = rect.width // set width to Constraint outlet

Swift 5 Answer who are using Constraint

label.text = "Hello World"

var rect: CGRect = label.frame //get frame of label
rect.size = (label.text?.size(withAttributes: [NSAttributedString.Key.font: UIFont(name: label.font.fontName , size: label.font.pointSize)!]))! //Calculate as per label font
labelWidth.constant = rect.width // set width to Constraint outlet