我试图计算基于不同字符串长度的UILabel的高度。

func calculateContentHeight() -> CGFloat{
    var maxLabelSize: CGSize = CGSizeMake(frame.size.width - 48, CGFloat(9999))
    var contentNSString = contentText as NSString
    var expectedLabelSize = contentNSString.boundingRectWithSize(maxLabelSize, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: [NSFontAttributeName: UIFont.systemFontOfSize(16.0)], context: nil)
    print("\(expectedLabelSize)")
    return expectedLabelSize.size.height

}

上面是我用来确定高度的当前函数,但它不起作用。如果能得到任何帮助,我将不胜感激。我更喜欢Swift的答案,而不是Objective C。


当前回答

这里有一个简单的解决方案,对我来说很有用。类似于其他发布的一些,但它不需要sizeToFit

注意这是用Swift 5写的

let lbl = UILabel()
lbl.numberOfLines = 0
lbl.font = UIFont.systemFont(ofSize: 12) // make sure you set this correctly 
lbl.text = "My text that may or may not wrap lines..."

let width = 100.0 // the width of the view you are constraint to, keep in mind any applied margins here
 
let height = lbl.systemLayoutSizeFitting(CGSize(width: width, height: UIView.layoutFittingCompressedSize.height), withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel).height

它处理行换行等。不是最优雅的代码,但它完成了工作。

其他回答

检查标签文本的高度和它正在工作

let labelTextSize = ((labelDescription.text)! as NSString).boundingRect(
                with: CGSize(width: labelDescription.frame.width, height: .greatestFiniteMagnitude),
                options: .usesLineFragmentOrigin,
                attributes: [.font: labelDescription.font],
                context: nil).size
            if labelTextSize.height > labelDescription.bounds.height {
                viewMoreOrLess.hide(byHeight: false)
                viewLess.hide(byHeight: false)
            }
            else {
                viewMoreOrLess.hide(byHeight: true)
                viewLess.hide(byHeight: true)

            }

在Swift 5中:

label.textRect(forBounds: label.bounds, limitedToNumberOfLines: 1)

顺便说一下,limitedToNumberOfLines的值取决于你想要的标签文本行。

extension String{

    func widthWithConstrainedHeight(_ height: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: CGFloat.greatestFiniteMagnitude, height: height)

        let boundingBox = self.boundingRect(with: constraintRect, options: NSStringDrawingOptions.usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)

        return ceil(boundingBox.width)
    }

    func heightWithConstrainedWidth(_ width: CGFloat, font: UIFont) -> CGFloat? {
        let constraintRect = CGSize(width: width, height: CGFloat.greatestFiniteMagnitude)
        let boundingBox = self.boundingRect(with: constraintRect, options: NSStringDrawingOptions.usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)

        return ceil(boundingBox.height)
    }

}
extension String {
    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)
    }
    
    func width(withConstraintedHeight height: CGFloat, font: UIFont) -> CGFloat {
        let constraintRect = CGSize(width: .greatestFiniteMagnitude, height: height)
        let boundingBox = self.boundingRect(with: constraintRect, options: .usesLineFragmentOrigin, attributes: [NSFontAttributeName: font], context: nil)
        
        return ceil(boundingBox.width)
    }
}

斯威夫特5:

如果你有UILabel和某种方式boundingRect不为你工作(我面临这个问题。它总是返回1行高)有一个扩展,可以轻松计算标签大小。

extension UILabel {
    func getSize(constrainedWidth: CGFloat) -> CGSize {
        return systemLayoutSizeFitting(CGSize(width: constrainedWidth, height: UIView.layoutFittingCompressedSize.height), withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel)
    }
}

你可以这样使用它:

let label = UILabel()
label.text = "My text\nIs\nAwesome"
let labelSize = label.getSize(constrainedWidth:200.0)

对我有用