KeyboardAdjustable+UILayoutGuide.swift

import UIKit
import Anchorage

protocol KeyboardAdjustable {

}

extension KeyboardAdjustable where Self: UIViewController {
    var keyboardLayoutGuide: UILayoutSupport {
        return keyboardLayoutGuideObject        
    }
    
    func configureWithBottomLayoutGuide(bottomLayoutGuide: UILayoutSupport) {
        let layoutGuide = keyboardLayoutGuideObject
        
        if !view.layoutGuides.contains(layoutGuide) {
            view.addLayoutGuide(layoutGuide)
            layoutGuide.bottomAnchor == bottomLayoutGuide.topAnchor
            layoutGuide.horizontalAnchors == view.horizontalAnchors
        }
    }
}

// MARK: - Private

private extension KeyboardAdjustable where Self: UIViewController {
    var keyboardLayoutGuideObject: KeyboardLayoutGuideObject {
        guard let object = objc_getAssociatedObject(self, &KeyboardLayoutGuideObject.associatedKey) as? KeyboardLayoutGuideObject else {
            let object = KeyboardLayoutGuideObject()
            objc_setAssociatedObject(self, &KeyboardLayoutGuideObject.associatedKey, object, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            
            return object
        }
        
        return object
    }
}

// MARK: - KeyboardLayoutGuide

class KeyboardLayoutGuideObject: UILayoutGuide, UILayoutSupport {
    static var associatedKey = "com.bradsmith.keyboardLayoutGuideObjectAssociatedKey"
    
    private var heightConstraint: NSLayoutConstraint?
    
    var length: CGFloat {
        return layoutFrame.height
    }
        
    override init() {
        super.init()
        
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillUpdate(_:)), name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillUpdate(_:)), name: UIKeyboardWillHideNotification, object: nil)
        
        heightConstraint = heightAnchor == 0.0
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {
        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
    }
}

// MARK: - Private

private extension KeyboardLayoutGuideObject {
    @objc func keyboardWillUpdate(notification: NSNotification) {
        let animationCurve = (notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber)?.unsignedIntegerValue ?? 0
        let animationDuration = (notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0.0
        let keyboardFrame = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue() ?? CGRect.zero
        let keyboardVisible = notification.name == UIKeyboardWillShowNotification
        let options = UIViewAnimationOptions(rawValue: animationCurve << 16)
        let animations: () -> Void = { [weak self] in
            self?.heightConstraint?.constant = keyboardVisible ? keyboardFrame.height : 0.0
            self?.owningView?.layoutIfNeeded()
        }
        
        UIView.animateWithDuration(animationDuration, delay: 0.0, options: options, animations: animations, completion: nil)
    }
}

KeyboardAdjustable.swift

import UIKit
import Anchorage

protocol KeyboardAdjustable {

}

extension KeyboardAdjustable where Self: UIViewController {
    var keyboardLayoutGuide: UILayoutSupport {
        return keyboardLayoutGuideObject        
    }
    
    func configureWithBottomLayoutGuide(bottomLayoutGuide: UILayoutSupport) {
        let layoutGuide = keyboardLayoutGuideObject
        
        if !view.subviews.contains(layoutGuide) {
            view.addSubview(layoutGuide)
            layoutGuide.bottomAnchor == bottomLayoutGuide.topAnchor
            layoutGuide.horizontalAnchors == view.horizontalAnchors
        }
    }
}

// MARK: - Private

private extension KeyboardAdjustable where Self: UIViewController {
    var keyboardLayoutGuideObject: KeyboardLayoutGuideObject {
        guard let object = objc_getAssociatedObject(self, &KeyboardLayoutGuideObject.associatedKey) as? KeyboardLayoutGuideObject else {
            let object = KeyboardLayoutGuideObject(frame: .zero)
            objc_setAssociatedObject(self, &KeyboardLayoutGuideObject.associatedKey, object, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
            
            return object
        }
        
        return object
    }
}

// MARK: - KeyboardLayoutGuide

class KeyboardLayoutGuideObject: UIView, UILayoutSupport {
    static var associatedKey = "com.bradsmith.keyboardLayoutGuideObjectAssociatedKey"
    
    private var heightConstraint: NSLayoutConstraint?
    
    var length: CGFloat {
        return bounds.height
    }
        
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillUpdate(_:)), name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(keyboardWillUpdate(_:)), name: UIKeyboardWillHideNotification, object: nil)
        
        heightConstraint = heightAnchor == 0.0
    }
    
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    deinit {
        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().removeObserver(self, name: UIKeyboardWillHideNotification, object: nil)
    }
}

// MARK: - Private

private extension KeyboardLayoutGuideObject {
    @objc func keyboardWillUpdate(notification: NSNotification) {
        let animationCurve = (notification.userInfo?[UIKeyboardAnimationCurveUserInfoKey] as? NSNumber)?.unsignedIntegerValue ?? 0
        let animationDuration = (notification.userInfo?[UIKeyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0.0
        let keyboardFrame = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.CGRectValue() ?? CGRect.zero
        let keyboardVisible = notification.name == UIKeyboardWillShowNotification
        let options = UIViewAnimationOptions(rawValue: animationCurve << 16)
        let animations: () -> Void = { [weak self] in
            self?.heightConstraint?.constant = keyboardVisible ? keyboardFrame.height : 0.0
            self?.superview?.layoutIfNeeded()
        }
        
        UIView.animateWithDuration(animationDuration, delay: 0.0, options: options, animations: animations, completion: nil)
    }
}