Extension of UIViewController with helpers methods to simplify embedding child view controllers. <Swift 3.0.2>

UIViewController+Embedded.swift

/*
 
 MIT License
 
 Copyright © 2017 Dmytro Kholodov
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
 
 */


import UIKit


/// Predefined Layouts for an embedded controller
enum BindLayoutOptions {
    /// Hidden. View of embedded controller is invisible. It can propagate 
    /// other view into the partent controller.
    case zero
    /// Fill size of the parent controller.
    case fill
    /// Custom callback. Custom layout and custom setup.
    typealias Callback = (_ childView: UIView) -> Void
    case custom(Callback)
}

///
/// UIViewController helpers to add and remove child view controllers.
///
extension UIViewController {
    
    /// Add child view controller with specified layout presets.
    /// - Parameters:
    ///   - child: controller to be added as a child controller
    ///   - layout: predefined layout
    func addController(embedded: UIViewController, layout: BindLayoutOptions = .fill) {
        addChildViewController(embedded)
        embedded.willMove(toParentViewController: self)
        setupView(child: embedded.view, layout: layout)
        embedded.didMove(toParentViewController: self)
    }

    /// Remove child view controller from the parent controller.
    /// - Parameters:
    ///   - child: a controller to be added as a child controller
    func removeController(embedded: UIViewController) {
        embedded.willMove(toParentViewController: nil)
        embedded.view.removeFromSuperview()
        embedded.removeFromParentViewController()
    }
    
    /// Layout the child view in the superview
    /// - Parameters:
    ///   - child: view to be added as a child controller
    ///   - layout: predefined layout
    private func setupView(child: UIView, layout: BindLayoutOptions) {
        view.addSubview(child)
        
        switch layout {
        case .zero:
            child.frame = CGRect.zero
            break
        case .fill:
            break
        case .custom(let callback):
            callback(child)
            break
        }
        
    }
}

Examples

`

    // Fill parent view
    addController(embedded: UIViewController())
    
    // Hidden view of child controller
    addController(embedded: UIViewController(), layout: .zero)
    
    
    // Custom layout
    addController(embedded: UIViewController(), layout:  .custom { $0.frame = CGRect(x: 0, y: 0, width: 100, height: 100) } )

`