EverLayout

EverLayout translates JSON/XML data into iOS layouts which can be downloaded, reused and updated at runtime.

Features

Create comprehensive layouts without the clumsiness of Interface Builder or view controllers bloated with layout code.
Downloadable layouts - Layouts written in JSON can be downloaded from a web server, meaning an App UI can be updated without having to submit for App Review.
Build layouts with real-time update using a simple HTTP server (or EverLayout Bridge).
A/B Testing - Testing multiple UIs with your users is easy when building a layout is just loading a file.

Installation

Cocoapods

Add EverLayout to your Podfile

platform :ios, '8.0'
use_frameworks!
pod 'Everlayout'

Carthage

Create a Cartfile that lists the framework and run carthage update.

github "acrocat/EverLayout"

EverLayout Bridge

EverLayout Bridge can be installed via Node Package Manager.

npm install -g ever-layout-bridge

More info here

Usage Example

Layout file

{
    "name":"ViewController",
    "root":{
        "views":{
            "exampleButton":{
                "constraints":{
                    "center":"@super",
                    "width":"+120",
                    "height":"+80"
                },
                "properties":{
                    "text":"Tap Me!"
                }
            }
        }
    }
}

Swift

import UIKit
import EverLayout

class ViewController: UIViewController {
    private var layout : EverLayout?
    public let exampleButton : UIButton = UIButton()

    override func viewDidLoad() {
        super.viewDidLoad()

        let layoutData = NSData(contentsOfFile: Bundle.main.path(forResource: "ViewController", ofType: "json", inDirectory: "Layouts")!) as! Data
        self.layout = EverLayout(layoutData: layoutData)
        self.layout?.build(onView: self.view, viewEnvironment: self)
    }
}

Simple Example

Basic example

{
    "name":"ViewController",
    "root":{
        "views":{
            "!redSquare":{
                "constraints": {
                    "width height":"+180",
                    "center":"@super <24"
                },
                "properties":{
                    "backgroundColor":"red"
                }
            }
        }
    }
}

Here I am running a blank application in the simulator side-by-side with a ViewController layout described in JSON, which is loaded by the default View Controller. The app has connected to EverLayout Bridge which is serving layout updates every time I save the layout file.

Every time I update the JSON, the App clears and rebuilds the layout with the new data.

In the example I am just changing the properties of a UIView to show how layouts can be designed/built without having to re-compile the app.

Discussion

At the moment EverLayout is more of an experiment than a solution. The idea was born through frustration of Interface Builder and the existing alternative of clunky layout code.

The goal of this project is to find a middle ground which can offer the real-time 'visual' approach of IB, and the flexibility and re-usability of layouts described with code.