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iOS Introduction to Auto Layout in iOS Auto Layout in Code Using Layout Anchors

Martel Storm
Martel Storm
4,157 Points
Posted by Martel Storm
Martel Storm
4,157 Points

Using Layout Anchors: I must be super close to the right answer! Little help?

I'm retarded

layout.swift 
class MyViewController: UIViewController {

    let blueView = UIView()
    let greenView = UIView()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(greenView)
        view.addSubview(blueView)
    }

    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        blueView.translatesAutoresizingMaskIntoConstraints = false
        greenView.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            NSLayoutConstraint(item: blueView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 100.0),
            NSLayoutConstraint(item: blueView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150.0),
            NSLayoutConstraint(item: blueView, attribute: .left, relatedBy: .equal, toItem: view, attribute: .leftMargin, multiplier: 1.0, constant: 8.0),
            NSLayoutConstraint(item: blueView, attribute: .top, relatedBy: .equal, toItem: self.topLayoutGuide, attribute: .bottom, multiplier: 1.0, constant: 8.0),
            NSLayoutConstraint(item: blueView, attribute: .right, relatedBy: .equal, toItem: view, attribute: .rightMargin, multiplier: 1.0, constant: -8.0)
        ])

        // Add constraint code below
        NSLayoutConstraint.activate([
            greenView.topAnchor.constraint(equalTo: blueView.bottomAnchor, constant: 8.0),
            greenView.leftAnchor.constraint(equalTo: view.layoutMarginsGuide.leftAnchor, constant: 8.0),
            greenView.rightAnchor.constraint(equalTo: view.layoutMarginsGuide.rightAnchor, constant: 8.0),
            greenView.heightAnchor.constraint(equalToConstant: 75)
            ])

    }
}

1 Answer

landonferrier
landonferrier
25,097 Points

Martel,

Here is the code that I got to pass the challenge: 

class MyViewController: UIViewController {

    let blueView = UIView()
    let greenView = UIView()

    override func viewDidLoad() {
        super.viewDidLoad()
        view.addSubview(greenView)
        view.addSubview(blueView)
    }

    override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()
        blueView.translatesAutoresizingMaskIntoConstraints = false
        greenView.translatesAutoresizingMaskIntoConstraints = false



        NSLayoutConstraint.activate([
            NSLayoutConstraint(item: blueView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 100.0),
            NSLayoutConstraint(item: blueView, attribute: .width, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 150.0),
            NSLayoutConstraint(item: blueView, attribute: .left, relatedBy: .equal, toItem: view, attribute: .leftMargin, multiplier: 1.0, constant: 8.0),
            NSLayoutConstraint(item: blueView, attribute: .top, relatedBy: .equal, toItem: self.topLayoutGuide, attribute: .bottom, multiplier: 1.0, constant: 8.0),
            NSLayoutConstraint(item: blueView, attribute: .right, relatedBy: .equal, toItem: view, attribute: .rightMargin, multiplier: 1.0, constant: -8.0)
        ])

        // Add constraint code below
       NSLayoutConstraint.activate([
        greenView.bottomAnchor.constraint(equalTo: view.bottomAnchor, constant: 8),
        greenView.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 8),
        greenView.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: 8),
        greenView.heightAnchor.constraint(equalToConstant: 75.0)
        ])

    }
}

When activating the constraints, you don't need to use the layout guide to get the anchors. These can be accessed directly from the "view" property. If you have any questions, feel free to ask.