AutoLayoutSwift

The library is aimed to help developers to apply complex AutoLayout structures in a few lines of code. The library is available under MIT license and is available over Cocoapods dependency manager.

Installation

The library is published over Cocoapods. To install, just add the following line to your podfile:

pod 'AutoLayoutSwift', '~> 3.2'

And run the following command in Terminal

pod install

Usage

Primary constraints

The official documentation about AutoLayout concepts can be found at Apple official documentation pages. However, the following descriptions enriched with screenshots might be helpful to understand the concept better. Before you deep into the following sections, please note that:

• The parameters in all functions are optional meaning you don't have to specify values for all anchors. The only specified anchors will be applied.
• The isRelative parameter determines if the anchor should be constrained by the corresponded anchor or not. For example, if you want to constraint the leading anchor of viewA to the trailing anchor of viewB, you may pass true for the parameter.
• Starting version 3.1, you can set constraints to safe area for supported devices running iOS 11 and upper
• The functions return UIView as the object, so it is possible to apply a chain of constraint to the target view. As an example:

viewA
  .fix(leading: (0, viewB) isRelative: true)
  .fix(top: (0, superview), bottom: (0, superview), toSafeArea: true, isRelative: false)
  .fix(height: 20)

leading, trailing

The leading and trailing anchors are referred also as left and right anchors respectively. To add constraints from viewA to viewB, you may use the following function.

viewA.fix(leading: (value, viewB), trailing: (value, viewB), isRelative: false

Top - Bottom

To add top or bottom constraints from viewA to viewB, you may use the following function:

viewA.fix(top: (value, viewB), bottom: (value, viewB), isRelative: false)

Width, Height, Aspect Ratio

To apply size constraints to viewB easily use the following function:

viewA.fix(width: 20, height: 30)

For applying an aspect ratio, you need to set a constraint for width OR height first, then by using the following function you can set an aspect ratio with respect to value you assigned to a size constraint first

viewA
  .fix(width: 20)
  .scale(aspectRatio: 2.0)

Helper functions

The following 2 functions help to have more control over the constraints in a view

Deactivate

Deactivate feature simply remove/disable the constraint for the view. For example, the following line will remove any constraints that are assigned to left and height anchors

viewA.deactivate(origin: [.left], size: [.height])

Constants

To get the current values that are assigned to specified constraints, use the following function to get an dictionary indicating the value and the constraint. For example, the following code which will get the values assigned to the size constraints, the result would be: [.width: value, .height: value]

viewA.constants(in: [.width, .height])