davidask / layoutaid

Declarative AutoLayout DSL and utilities for iOS, tvOS, and macOS

LayoutAid

AutoLayout extensions for iOS, macOS, and tvOS.

Features

• Declarative DSL for creating layout constraints
• keyboardLayoutGuide for UIView on iOS, fully animatable
• keyboardSafeAreaLayoutGuide for UIView on iOS, fully animatable
• Extensions for UIScrollView adjusting contentInset based on keyboard appearance

Requirements

• iOS 11+
• tvOS 11+
• macOS 10.11+

Installation

Carthage

Create a Cartfile that lists the framework and run carthage update. Follow the instructions to add $(SRCROOT)/Carthage/Build/iOS/LayoutAid.framework to an iOS project.

github "davidask/LayoutAid"

Swift Package Manager

This project has support for Swift Package Manager.

Usage

To use the extensions provided in this library, you must import LayoutAid.

Layout DSL

NSLayoutConstraint.activate {
    containerView.anchor(
        Edges(equalTo: view.layoutMarginsGuide)
    )

    iconView.anchor {
        Width(equalTo: 50)
        AspectRatio(equalTo: 1)
        Center(equalTo: containerView)
    }

    label.anchor {
        Top(equalToSystemSpacingBelow: iconView)
        CenterX(equalTo: containerView.readableContentGuide)
        Width(lessThanOrEqualTo: containerView.readableContentGuide, multiplier: 0.5)
    }
}

Constraints are best activated in bulk, however, creating complex layouts can get verbose, even with layout anchors. This library provides two static methods on NSLayoutConstraint using function builders:

• build, for creating constraints using a function builder
• activate, for creating and activating constraints using a function builder

To constrain a view or layout guide use view.anchor or layoutGuide.anchor. Constrain blocks can be used inside NSLayoutConstraint.build or NSLayoutConstraint.activate.

This library aligns its semantics with Apples layout anchor API, meaning that you'll find a constraint builder for each anchor type, including convenience builders.

• Leading
• Trailing
• Left
• Right
• Top
• Bottom
• CenterX
• CenterY
• Center
• Edges
• DirectionalEdges
• Size
• AspectRatio

Keyboard layout guides

Keyboard management in iOS can be tricky. This library provides a lazy accessor to keyboardLayoutGuide and keyboardSafeAreaLayoutGuide. Backed by a Keyboard type observing the keyboard state this allows you to easily layout your views with the keyboard in mind.

NSLayoutConstraint.activate {
    keyboardBackgroundView.anchor(
        Edges(equalTo: view.keyboardLayoutGuide)
    )

    keyboardAvoidingView.anchor {
        Leading(equalTo: view)
        Trailing(equalTo: view)
        Top(equalTo: view.safeAreaLayoutGuide)
        Bottom(lessThanOrEqualTo: view.keyboardSafeAreaLayoutGuide)
    }
}

UIScrollView extensions

This library can automatically adjust contentInset of UIScrollView based on keyboard appearance using

• UIScrollView.adjustContentInsetForKeyboard(), to immediately adjust scroll view insets to keyboard
• UIScrollView.beginAdjustingContentInsetForKeyboard(), to start observing keyboard adjusting scroll view insets automatically
• UIScrollView.endAdjustingContentInsetForKeyboard(), to stop observing keyboard adjusting scroll view insets automatically

Contribute

Please feel welcome contributing to LayoutAid, check the LICENSE file for more info.

Credits

David Ask