Swift 3 Crie UILabel programaticamente e adicione NSLayoutConstraints

Question

Oct 28, 2016, 08:21 AM

nslayoutconstraint swift3 uilabel ios programmatically-created

Swift 3 Crie UILabel programaticamente e adicione NSLayoutConstraints

Olá, estou tentando criar um rótulo programaticamente e adicionar NSLayoutConstraints para que ele seja centralizado na superview, independentemente do tamanho e orientação da tela, etc. Procurei, mas não consigo encontrar um exemplo a seguir. Aqui está o que eu tenho:

let codedLabel:UILabel = UILabel()
codedLabel.frame = CGRect(x: 100, y: 100, width: 200, height: 200)
codedLabel.textAlignment = .center
codedLabel.text = alertText
codedLabel.numberOfLines=1
codedLabel.textColor=UIColor.red
codedLabel.font=UIFont.systemFont(ofSize: 22)
codedLabel.backgroundColor=UIColor.lightGray

let heightConstraint:NSLayoutConstraint = NSLayoutConstraint(item: codedLabel, attribute: NSLayoutAttribute.height, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 200)

let widthConstraint:NSLayoutConstraint = NSLayoutConstraint(item: codedLabel, attribute: NSLayoutAttribute.width, relatedBy: NSLayoutRelation.equal, toItem: nil, attribute: NSLayoutAttribute.notAnAttribute, multiplier: 1, constant: 200)

codedLabel.addConstraints([heightConstraint, widthConstraint])

let verticalConstraint:NSLayoutConstraint = NSLayoutConstraint(item: codedLabel, attribute: NSLayoutAttribute.centerY, relatedBy: NSLayoutRelation.equal, toItem: self.contentView, attribute: NSLayoutAttribute.centerY, multiplier: 1, constant: 0)

let horizontalConstraint:NSLayoutConstraint = NSLayoutConstraint(item: codedLabel, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: self.contentView, attribute: NSLayoutAttribute.centerX, multiplier: 1, constant: 0)

self.contentView.addConstrai,nts([verticalConstraint, horizontalConstraint])

self.contentView.addSubview(codedLabel)

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