Extend iOS 11 Safe Area to include the keyboard

Question

The new Safe Area layout guide introduced in iOS 11 works great to prevent content from displaying below bars, but it excludes the keyboard. That means that when a keyboard

Answer 1

I use a different approach. I have a view (KeyboardProxyView) that I add to my view hierarchy. I pin this to the bottom of the main view, and adjust its height with the keyboard. This means we can treat the keyboardProxy as if it is the keyboard view - except that it is a normal view, so you can use constraints on it.

This allows me to constrain my other views relative to the keyboardProxy manually.

e.g. - my toolbar isn't constrained at all, but I might have inputField.bottom >= keyboardProxy.top

Code below (note - I use HSObserver and PureLayout for notifications and autolayout - but you could easily rewrite that code if you prefer to avoid them)

import Foundation
import UIKit
import PureLayout
import HSObserver

/// Keyboard Proxy view will mimic the height of the keyboard
/// You can then constrain other views to move up when the KeyboardProxy expands using AutoLayout
class KeyboardProxyView: UIView, HSHasObservers {
    weak var keyboardProxyHeight: NSLayoutConstraint!

    override func didMoveToSuperview() {
        keyboardProxyHeight = self.autoSetDimension(.height, toSize: 0)

        let names = [UIResponder.keyboardWillShowNotification,UIResponder.keyboardWillHideNotification]
        HSObserver.init(forNames: names) { [weak self](notif) in
            self?.updateKeyboardProxy(notification: notif)
        }.add(to: self)

        activateObservers()
    }

    var parentViewController: UIViewController? {
        var parentResponder: UIResponder? = self
        while parentResponder != nil {
            parentResponder = parentResponder!.next
            if let viewController = parentResponder as? UIViewController {
                return viewController
            }
        }
        return nil
    }

    func updateKeyboardProxy(notification:Notification){
        let userInfo = notification.userInfo!

        let animationDuration = (userInfo[UIResponder.keyboardAnimationDurationUserInfoKey] as! NSNumber).doubleValue
        let keyboardEndFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as! NSValue).cgRectValue
        let convertedKeyboardEndFrame = self.superview!.convert(keyboardEndFrame, from: self.window)
        let rawAnimationCurve = (notification.userInfo![UIResponder.keyboardAnimationCurveUserInfoKey] as! NSNumber).uint32Value << 16
        let animationCurve = UIView.AnimationOptions(rawValue:UInt(rawAnimationCurve))

        keyboardProxyHeight.constant = self.superview!.bounds.maxY - convertedKeyboardEndFrame.minY
        //keyboardProxyHeight.constant = keyboardEndFrame.height

        UIView.animate(withDuration: animationDuration, delay: 0.0, options: [.beginFromCurrentState, animationCurve], animations: {
            self.parentViewController?.view.layoutIfNeeded()
        }, completion: nil)
    }
}