Đinh Quang Hiếu Đinh Quang Hiếu - 6 months ago 41
Swift Question

Autolayout programmatically with UILabel doesn't work

So I want to center horizontal and vertical a UILabel in my View programmatically. I follow this topic but it doesn't work. How can I do that?

p/s: this is my code:

class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let noDataLabel = UILabel()
noDataLabel.text = "No data :("
noDataLabel.textColor = UIColor.redColor()
noDataLabel.font = UIFont.systemFontOfSize(20)
noDataLabel.sizeToFit()
self.view.addSubview(noDataLabel)
NSLayoutConstraint(item: noDataLabel, attribute: .CenterX, relatedBy: .Equal, toItem: self.view, attribute: .CenterX, multiplier: 1.0, constant: 0.0).active = true
NSLayoutConstraint(item: noDataLabel, attribute: .CenterY, relatedBy: .Equal, toItem: self.view, attribute: .CenterY, multiplier: 1.0, constant: 0.0).active = true
}
}

Answer

Add this to your code:

 noDataLabel.translatesAutoresizingMaskIntoConstraints = false

From apple documentation:

By default, the autoresizing mask on a view gives rise to constraints that fully determine the view's position. This allows the auto layout system to track the frames of views whose layout is controlled manually (through -setFrame:, for example). When you elect to position the view using auto layout by adding your own constraints, you must set this property to NO. IB will do this for you.