GTEasyLayout

What is GTEasyLayout?

GTEasyLayout is a small framework written in Swift which aims to minimise the effort of setting up constraints programmatically when implementing UI in iOS apps. It's the perfect tool to use when constraints are not extremely complicated and typing a bunch of similar lines for multiple views becomes tiring and anti-productive.

GTEasyLayout is composed by:

1. The GTEasyLayoutAdaptable Swift protocol which defines methods that automate the constraint configuration process. An extension with default implementation is included so the aimed functionality exists instantly and out of the box.
2. The GTEasyLayout class which is just a namespace for custom defined types. There should not be created instances of this class as there are not any available properties or methods to access.

The main idea behind the current implementation is that a subview snaps to all or some of the edges of the container view. It's possible to specify spacing (padding) between the subview and the container view on any side, to provide the size of the view, as well as to animate changes to the padding and size dimensions (meaning to change the constraints that control the position and size of the subview animated).

Here is the protocol definition:

public protocol GTEasyLayoutAdaptable {

    func add(view: UIView, to targetView: UIView, snapTo edges: GTEasyLayout.SnapEdges, padding: UIEdgeInsets, size: CGSize)

    func updatePadding(at side: GTEasyLayout.Side, ofView view: UIView, newValue: CGFloat, animationSettings: GTEasyLayout.AnimationSettings?, completion: (()-> Void)?)

    func updateDimension(_ dimension: GTEasyLayout.Dimension, ofView view: UIView, newValue: CGFloat, animationSettings: GTEasyLayout.AnimationSettings?, completion: (() -> Void)?)
}

See the GTEasyLayout.swift file for documentation on the custom types appearing above and the GTEasyLayoutAdaptable.swift for documentation regarding each method. You can find all that at this generated documentation by jazzy.

---

Integration

GTEasyLayout can be integrated into a project in two different ways:

Using CocoaPods

In your Podfile add:

pod 'GTEasyLayout'

Remember to import the framework anywhere you are about to use it:

import GTEasyLayout

Manually

Download or clone this repository, then add the Source directory along with the two contained files into your project.

---

Usage Examples

Note: See the wiki for detailed examples along with visual representation of the results, or open the sample project in Xcode to see everything in action.

First, make your class conform to the GTEasyLayoutAdaptable protocol:

class ViewController: UIViewController, GTEasyLayoutAdaptable {
    ...
}

Into the point now:

Snap a subview to all edges of the view controller's root view leaving 50px padding from all sides:

add(view: someView,
    to: self.view,
    snapTo: .all,
    padding: UIEdgeInsets(all: 50.0),
    size: .zero)

Snap to top, left, bottom and set the width to 250px. Height will be 0.0, as it's calculated automatically:

add(view: myView,
    to: self.view,
    snapTo: .topLeftBottom,
    padding: UIEdgeInsets(top: 20.0, left: 0.0, bottom: 0.0, right: 0.0),
    size: CGSize(width: 250.0, height: 0.0))

Center both horizontally and vertically a view with size 200x150px:

add(view: someView,
    to: self.view,
    snapTo: .centerX_Y,
    padding: .zero,
    size: CGSize(width: 200.0, height: 150.0))

Updating the padding on the left side animated:

let animSettings = GTEasyLayout.AnimationSettings(withDuration: 0.5, delay: 0.0, damping: 0.7, velocity: 1.0, options: .curveLinear)

updatePadding(at: .left,
              ofView: someView,
              newValue: 150.0,
              animationSettings: animSettings,
              completion: nil)

Animating the change of the height dimension (passing nil to animationSettings will make the following method use default animation settings):

updateDimension(.height,
                ofView: someView,
                newValue: 400.0,
                animationSettings: nil,
                completion: nil)

If you don't want to animate changes on constraints, then initialize a GTEasyLayout.AnimationSettings object and set the duration to zero.

---

Other Notes

GTEasyLayout is a work in progress, and new functionalities will be added over the course of time.

Created with ❤️ by Gabriel Theodoropoulos ([email protected]) and it is provided under the MIT license.