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

Posted by Marc Biggar
Marc Biggar
12,486 Points

I have no idea what to do here , please help

In the editor, you've been provided with a view controller subclass that contains two instances of UIView as stored properties. The code to set up blueView has already been written; you need to set up greenView.

To set up the green view add the following constraints:

Pin to the bottom of blueView with 8 point spacing
Pin to left and right margins with 8 point spacing
Add height constraint of 75 points.
For this exercise you may use the verbose NSLayoutConstraint APIs or layout anchors to create constraints.
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


    }
}

1 Answer

Allen Soberano
Allen Soberano
13,634 Points
Allen Soberano
Allen Soberano
13,634 Points

This is the code for the blue view with specific constraints. You need to do the excavation same thing for the green view but with specified specs

  NSLayoutConstraint.activate([
        NSLayoutConstraint(item: blueView, attribute: .height, relatedBy: .equal, toItem: nil, attribute: .notAnAttribute, multiplier: 1.0, constant: 100.0)

........

Marc Biggar
Marc Biggar
12,486 Points

Thanks - figured it out in the end - was over complicating it :)

Allen Soberano
Allen Soberano
13,634 Points

No worries. I think we all tend to overthink our answers. Just glad I was able to help.