ios - 在Swift中自动调整多行UILabel的大小

Question

我已经尝试了一切以在Swift中自动调整UILabel的大小。当文本为一行时，我可以自动调整大小，但是当文本为两行时，它将不再起作用。 UILabel中的文本更改通常大约每10秒发生一次。我尝试过的代码是:

let direction = UILabel(frame: CGRect(x: 95, y: 10, width: screenWidth - 95, height:100))
direction.numberOfLines = 0
direction.adjustsFontSizeToFitWidth = true
direction.lineBreakMode = .byWordWrapping
direction.textAlignment = .center
direction.minimumScaleFactor = 0.2
direction.font = UIFont.boldSystemFont(ofSize: 40)
view.addSubview(direction)
direction.text = "Ffafdafafdfa fafda  dfafaf afa"

func updateDirection(update: String){
    direction.text = update
} 

原始文本“Ffafdafafdfa fafda dfafaf afa”将自动调整大小，但是在调用updateDirection时，字体大小未从40更改。我还尝试将行数设置为2，并删除.byWordWrapping。如何获得UILabel自动调整大小？

Answer 1

下面的代码将frame size和adjust the font size与direction label content保持一致。

let backgroundView = UIView(frame: CGRect(x: 5, y: UINavigationController().navigationBar.frame.height + UIApplication.shared.statusBarFrame.height, width: UIScreen.main.bounds.width - 10, height: UIScreen.main.bounds.width - 100))
let direction = UILabel()

 override func viewDidLoad() {
    super.viewDidLoad()

 direction.backgroundColor = UIColor.green
 direction.numberOfLines = 0
 direction.textAlignment = .center
 direction.font = UIFont.boldSystemFont(ofSize: 40)
 direction.adjustsFontForContentSizeCategory = true
 direction.adjustsFontSizeToFitWidth = true
 direction.text = "This is some multiline label with a background colour" // Set or Initiate random function for your array here.

 backgroundView.backgroundColor = UIColor.red
 view.addSubview(backgroundView)
 backgroundView.addSubview(direction)

 Timer.scheduledTimer(timeInterval: 10.0, target: self, selector: #selector(random), userInfo: nil, repeats: true)  

 direction.translatesAutoresizingMaskIntoConstraints = false

 NSLayoutConstraint(item: direction,
                       attribute: .leading,
                       relatedBy: .equal,
                       toItem: backgroundView,
                       attribute: .leadingMargin,
                       multiplier: 1.0,
                       constant: 0.0).isActive = true

NSLayoutConstraint(item: direction,
                       attribute: .trailing,
                       relatedBy: .equal,
                       toItem: backgroundView,
                       attribute: .trailingMargin,
                       multiplier: 1.0,
                       constant: 0.0).isActive = true


NSLayoutConstraint(item: direction,
                       attribute: .top,
                       relatedBy: .equal,
                       toItem: backgroundView,
                       attribute: .topMargin,
                       multiplier: 1.0,
                       constant: 0.0).isActive = true

NSLayoutConstraint(item: direction,
                       attribute: .bottom,
                       relatedBy: .equal,
                       toItem: backgroundView,
                       attribute: .bottomMargin,
                       multiplier: 1.0,
                       constant: 0.0).isActive = true


}

func random(sender: Timer) {

    //Place your random func code here.     
}

输出: