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iOS Introduction to Auto Layout in iOS Auto Layout in Code Constraints in Code

Martel Storm
Martel Storm
4,157 Points

Constraints in Code: Code Challenge: It says I can't use an array. I say bologna! Where did I mess up?

I might be retarded

layout.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
        func sampleViewConstraints() {
            sampleView.translatesAutoresizingMaskIntoConstraints = false

            let sampleViewCenterX = NSLayoutConstraint(item: sampleView, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1.0, constant: 0.0)

            let sampleViewCenterY = NSLayoutConstraint(item: sampleView, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1.0, constant: 0.0)

            let sampleViewHeight = NSLayoutConstraint(item: sampleView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 50.0)

            let sampleViewWidth = NSLayoutConstraint(item: sampleView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 50.0)

            view.addConstraint([
                sampleViewWidth,
                sampleViewHeight,
                sampleViewCenterX,
                sampleViewCenterY])
        }
    }
}

1 Answer

Aniruddha Shukla
Aniruddha Shukla
2,846 Points

The method name is addConstraints and not addConstraint. It takes in an array of Constraints. Also, another thing that I see off is whats another method doing in the viewWillLayoutSubviews?

Try this with the fixed changes

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
            sampleView.translatesAutoresizingMaskIntoConstraints = false

            let sampleViewCenterX = NSLayoutConstraint(item: sampleView, attribute: .centerX, relatedBy: .equal, toItem: view, attribute: .centerX, multiplier: 1.0, constant: 0.0)

            let sampleViewCenterY = NSLayoutConstraint(item: sampleView, attribute: .centerY, relatedBy: .equal, toItem: view, attribute: .centerY, multiplier: 1.0, constant: 0.0)

            let sampleViewHeight = NSLayoutConstraint(item: sampleView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 50.0)

            let sampleViewWidth = NSLayoutConstraint(item: sampleView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 50.0)

            view.addConstraints([
                sampleViewWidth,
                sampleViewHeight,
                sampleViewCenterX,
                sampleViewCenterY])

    }
}