The answer is
You need to create an extension of String and call this method
func height(withConstrainedWidth width: CGFloat, font: UIFont) -> CGFloat {
let constraintRect = CGSize(width: width, height: .greatestFiniteMagnitude)
let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
return ceil(boundingBox.height)
}
You must send the width of your label
If you are using a UILabel with attributes, you can try the method textRect(forBounds:limitedToNumberOfLines).
This is my example:
let label = UILabel(frame: CGRect(x: 0, y: 0, width: 100, height: 30))
label.numberOfLines = 0
label.text = "Learn how to use RxSwift and RxCocoa to write applications that can react to changes in your underlying data without you telling it to do so."
let rectOfLabel = label.textRect(forBounds: CGRect(x: 0, y: 0, width: 100, height: CGFloat.greatestFiniteMagnitude), limitedToNumberOfLines: 0)
let rectOfLabelOneLine = label.textRect(forBounds: CGRect(x: 0, y: 0, width: 100, height: CGFloat.greatestFiniteMagnitude), limitedToNumberOfLines: 1)
let heightOfLabel = rectOfLabel.height
let heightOfLine = rectOfLabelOneLine.height
let numberOfLines = Int(heightOfLabel / heightOfLine)
And my results on the Playground:
Without calling sizeToFit, you can do this all numerically with a very plug and play solution:
+ (CGFloat)heightForText:(NSString*)text font:(UIFont*)font withinWidth:(CGFloat)width {
CGSize size = [text sizeWithAttributes:@{NSFontAttributeName:font}];
CGFloat area = size.height * size.width;
CGFloat height = roundf(area / width);
return ceilf(height / font.lineHeight) * font.lineHeight;
}
I use it a lot for UITableViewCells that have dynamically allocated heights.
Solves the attributes problem as well @Salman Zaidi.
This is the extension I use for calculating multiline UILabel heights, it's an adjusted snippet from a previous stack overflow post:
extension UILabel {
func estimatedHeight(forWidth: CGFloat, text: String, ofSize: CGFloat) -> CGFloat {
let size = CGSize(width: forWidth, height: CGFloat(MAXFLOAT))
let options = NSStringDrawingOptions.usesFontLeading.union(.usesLineFragmentOrigin)
let attributes = [NSFontAttributeName: UIFont.systemFont(ofSize: ofSize)]
let rectangleHeight = String(text).boundingRect(with: size, options: options, attributes: attributes, context: nil).height
return ceil(rectangleHeight)
}
}
CGSize maxSize = CGSizeMake(lbl.frame.size.width, CGFLOAT_MAX);
CGSize requiredSize = [lbl sizeThatFits:maxSize];
CGFloat height=requiredSize.height
To get height for the NSAttributedString use this function below. Where width - the width of your UILabel or UITextView
func getHeight(for attributedString: NSAttributedString, font: UIFont, width: CGFloat) -> CGFloat {
let textStorage = NSTextStorage(attributedString: attributedString)
let textContainter = NSTextContainer(size: CGSize(width: width, height: CGFloat.greatestFiniteMagnitude))
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainter)
textStorage.addLayoutManager(layoutManager)
textStorage.addAttribute(NSAttributedString.Key.font, value: font, range: NSMakeRange(0, textStorage.length))
textContainter.lineFragmentPadding = 0.0
layoutManager.glyphRange(for: textContainter)
return layoutManager.usedRect(for: textContainter).size.height
}
To get height for String use this function, It is almost identical like the previous method:
func getHeight(for string: String, font: UIFont, width: CGFloat) -> CGFloat {
let textStorage = NSTextStorage(string: string)
let textContainter = NSTextContainer(size: CGSize(width: width, height: CGFloat.greatestFiniteMagnitude))
let layoutManager = NSLayoutManager()
layoutManager.addTextContainer(textContainter)
textStorage.addLayoutManager(layoutManager)
textStorage.addAttribute(NSAttributedString.Key.font, value: font, range: NSMakeRange(0, textStorage.length))
textContainter.lineFragmentPadding = 0.0
layoutManager.glyphRange(for: textContainter)
return layoutManager.usedRect(for: textContainter).size.height
}
To summarize, you can calculate the height of a label by using its string and calling boundingRectWithSize. You must provide the font as an attribute, and include .usesLineFragmentOrigin for multi-line labels.
let labelWidth = label.frame.width
let maxLabelSize = CGSize(width: labelWidth, height: CGFloat.greatestFiniteMagnitude)
let actualLabelSize = label.text!.boundingRect(with: maxLabelSize, options: [.usesLineFragmentOrigin], attributes: [.font: label.font], context: nil)
let labelHeight = actualLabelSize.height(withWidth:labelWidth)
Some extensions to do just that:
Swift Version:
extension UILabel {
func textHeight(withWidth width: CGFloat) -> CGFloat {
guard let text = text else {
return 0
}
return text.height(withWidth: width, font: font)
}
func attributedTextHeight(withWidth width: CGFloat) -> CGFloat {
guard let attributedText = attributedText else {
return 0
}
return attributedText.height(withWidth: width)
}
}
extension String {
func height(withWidth width: CGFloat, font: UIFont) -> CGFloat {
let maxSize = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
let actualSize = self.boundingRect(with: maxSize, options: [.usesLineFragmentOrigin], attributes: [.font : font], context: nil)
return actualSize.height
}
}
extension NSAttributedString {
func height(withWidth width: CGFloat) -> CGFloat {
let maxSize = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
let actualSize = boundingRect(with: maxSize, options: [.usesLineFragmentOrigin], context: nil)
return actualSize.height
}
}
Objective-C Version:
UILabel+Utility.h
#import <UIKit/UIKit.h>
@interface UILabel (Utility)
- (CGFloat)textHeightForWidth:(CGFloat)width;
- (CGFloat)attributedTextHeightForWidth:(CGFloat)width;
@end
UILabel+Utility.m
@implementation NSString (Utility)
- (CGFloat)heightForWidth:(CGFloat)width font:(UIFont *)font {
CGSize maxSize = CGSizeMake(width, CGFLOAT_MAX);
CGSize actualSize = [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : font} context:nil].size;
return actualSize.height;
}
@end
@implementation NSAttributedString (Utility)
- (CGFloat)heightForWidth:(CGFloat)width {
CGSize maxSize = CGSizeMake(width, CGFLOAT_MAX);
CGSize actualSize = [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin context:nil].size;
return actualSize.height;
}
@end
@implementation UILabel (Utility)
- (CGFloat)textHeightForWidth:(CGFloat)width {
return [self.text heightForWidth:width font:self.font];
}
- (CGFloat)attributedTextHeightForWidth:(CGFloat)width {
return [self.attributedText heightForWidth:width];
}
@end
if you want the label to take dynamic lines you may use this
label.numberOfLines = 0; // allows label to have as many lines as needed
label.text = @"some long text ";
[label sizeToFit];
NSLog(@"Label's frame is: %@", NSStringFromCGRect(label.frame));
The current solution has been deprecated as of iOS 7.
Here is an updated solution:
+ (CGFloat)heightOfCellWithIngredientLine:(NSString *)ingredientLine
withSuperviewWidth:(CGFloat)superviewWidth
{
CGFloat labelWidth = superviewWidth - 30.0f;
// use the known label width with a maximum height of 100 points
CGSize labelContraints = CGSizeMake(labelWidth, 100.0f);
NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
CGRect labelRect = [ingredientLine boundingRectWithSize:labelContraints
options:NSStringDrawingUsesLineFragmentOrigin
attributes:nil
context:context];
// return the calculated required height of the cell considering the label
return labelRect.size.height;
}
The reason that my solution is set up like this is because I am using a UITableViewCell and resizing the cell dynamically relative to how much room the label will take up.
Calling -sizeToFit on UILabel instance will automatically resize it to fit text it displays, no calculating required. If you need the size, you can get it from label's frame property after that.
label.numberOfLines = 0; // allows label to have as many lines as needed
label.text = @"some long text";
[label sizeToFit];
NSLog(@"Label's frame is: %@", NSStringFromCGRect(label.frame));
Copy & paste this method & used It like:
[lblText setFrame:CGRectMake(lblText.frame.origin.x, lblText.frame.origin.y, width, [self getLabelHeight:lblText])];
- (CGFloat)getLabelHeight:(UILabel*)label
{
CGSize constraint = CGSizeMake(label.frame.size.width, CGFLOAT_MAX);
CGSize size;
NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
CGSize boundingBox = [label.text boundingRectWithSize:constraint
options:NSStringDrawingUsesLineFragmentOrigin
attributes:@{NSFontAttributeName:label.font}
context:context].size;
size = CGSizeMake(ceil(boundingBox.width), ceil(boundingBox.height));
return size.height;
}
In my case, I was using a fixed size header for each section but with a dynamically cell size in each header. The cell's height, depends on the label's height.
Working with:
tableView.estimatedRowHeight = SomeNumber
tableView.rowHeight = UITableViewAutomaticDimension
Works but when using:
tableView.reloadSections(IndexSet(integer: sender.tag) , with: .automatic)
when a lot of headers are not collapsed, creates a lot of bugs such as header duplication (header type x below the same type) and weird animations when the framework reloads with animation, even when using with type .none (FYI, a fixed header height and cell height works).
The solution is making the use of heightForRowAt callback and calculate the height of the label by your self (plus the animation looks a lot better). Remember that the height is being called first.
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat
{
let object = dataDetailsController.getRowObject(forIndexPath: indexPath)
let label = UILabel(frame: tableView.frame)
let font = UIFont(name: "HelveticaNeue-Bold", size: 25)
label.text = object?.name
label.font = font
label.numberOfLines = 0
label.textAlignment = .center
label.sizeToFit()
let size = label.frame.height
return Float(size) == 0 ? 34 : size
}
To make UILabel fit the dynamic content you can use lines property in property inspector and set that as 0.
And you don't require to do any coding for this.
For more details you can check below demonstration video
Source: Stackoverflow.com