swift - 如何在Swift中将多行文本居中于UILabel？

我想以编程方式将一个带有多行文本的标签居中。我已经将它添加到以下约束中，但它只是显示在一行上！如何让它显示多行而不超出屏幕边界？

let noResults = UILabel()

noResults.text = self.emptyMessage
noResults.lineBreakMode = .byWordWrapping

noResults.minimumScaleFactor = 0.5
noResults.textAlignment = .center
noResults.font = UIFont(name: "Montserrat-Light", size: 20.0)!
noResults.numberOfLines = 0
noResults.adjustsFontSizeToFitWidth = true

noResults.sizeToFit()


noResults.textColor = UIColor.lightGray
noResults.translatesAutoresizingMaskIntoConstraints = false

self.view.addSubview(noResults)

let yConstraint = NSLayoutConstraint(item: noResults, attribute: .centerY, relatedBy: .equal, toItem: noResults.superview, attribute: .centerY, multiplier: 1, constant: -(self.navigationController?.navigationBar.frame.height)!)
let xConstraint = NSLayoutConstraint(item: noResults, attribute: .centerX, relatedBy: .equal, toItem: noResults.superview, attribute: .centerX, multiplier: 1, constant: 0)


NSLayoutConstraint.activate([yConstraint, xConstraint])

最佳答案

你只需要添加一个宽度限制。