BaiTapAutoLayout

BaiTapAutoLayout.swift

class MyViewController: UIViewController {
    
    let sampleView = UIView()
    
    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(sampleView)
    }
    
    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        sampleView.translatesAutoresizingMaskIntoConstraints = false
        
        // Add constraints below
        
        let sampleViewHeightConstraint = NSLayoutConstraint(item: sampleView, attribute: .Height, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant: 50.0)
        
        let sampleViewWidthConstraint = NSLayoutConstraint(item: sampleView, attribute: .Width, relatedBy: .Equal, toItem: nil, attribute: .NotAnAttribute, multiplier: 1.0, constant: 50.0)
        
        let sampleViewCenterXConstraint = NSLayoutConstraint(item: sampleView, attribute: .CenterX, relatedBy: .Equal, toItem: view, attribute: .CenterX, multiplier: 1.0, constant: 0.0)
        
        let sampleViewCenterYConstraint = NSLayoutConstraint(item: sampleView, attribute: .CenterY, relatedBy: .Equal, toItem: view, attribute: .CenterY, multiplier: 1.0, constant: 0.0)
    
        view.addConstraints([
            sampleViewHeightConstraint,
            sampleViewWidthConstraint,
            sampleViewCenterXConstraint,
            sampleViewCenterYConstraint
        ])
    }
}