Quick Layout Macro

QuickLayout supports fast, automatic layout management for UIKit views. This is achieved by prepending @QuickLayout to your view's declaration. @QuickLayout supports a number of features, including automatic layout, subview management, and sizing. It is the recommended way of integrating QuickLayout, although manual integration is still available when needed.

The snippet below demonstrates a simple @QuickLayout view:

import QuickLayout

@QuickLayout
final class MyView: UIView {

  private let label = {
    let label = UILabel()
    label.text = "Hello World!"
    return label
  }()

  private let image = {
    let image = UIImageView()
    image.image = UIImage(systemName: "globe.americas")
    return image
  }()

  var body: Layout {
    HStack {
      label
      Spacer(8)
      image
    }
  }
}

Note

Views that utilize @QuickLayout will automatically manage their view hierarchy. Therefore, there is no need to call addSubviews/removeFromSuperview manually.

Stateful View

When the state of a view changes, call setNeedsLayout. This will prompt the view to update its hierarchy, animate any added or removed views, and re-layout all subviews. The snippet below demonstrates an example of a stateful view. It lazily creates the label view when the user presses the increaseButton for the first time and updates the layout accordingly.

@QuickLayout
final class CounterView: UIView {

  private var count = 0

  private lazy var label {
    // This view will only be created when the count is set to 1 for the first time.
    UILabel()
  }

  private lazy var increaseButton = {
    let button = UIButton(type: .system)
    button.setTitle("Increase", for: .normal)
    button.addTarget(self, action: #selector(addCount), for: .touchUpInside)
    return button
  }()

  private lazy var resetButton = {
    let button = UIButton(type: .system)
    button.setTitle("Reset", for: .normal)
    button.addTarget(self, action: #selector(resetCount), for: .touchUpInside)
    return button
  }()

  var body: Layout {
    VStack(spacing: 8) {
      if count > 0 {
        label
      }
      HStack(spacing: 8) {
        increaseButton
        resetButton
      }
    }
  }

  @objc private func addCount() {
    count += 1
    label.text = "Count: \(count)"
    setNeedsLayout()
  }

  @objc private func resetCount() {
    count = 0
    setNeedsLayout()
  }
}

Advanced @QuickLayout Usage

It is possible to continue overriding layoutSubviews and even sizeThatFits while utilizing the @QuickLayout macro. When doing so:

• layoutSubviews will perform body layout directly after super.layoutSubviews() is called.
• sizeThatFits will override the default body sizing, allowing you to return something fully custom.

Additionally, the following methods are available to override:

• isBodyEnabled: this allows you to toggle automatic layout management. It's a great way to test a migration to QuickLayout in-place.
• bodyContainerView: this changes the view that subviews are managed within. Collection view and table view cells utilize this to ensure views are placed on contentView.