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Make UIViewControllers automatically aware of the keyboard
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| // | |
| // UIViewController+KeyboardAware.swift | |
| // | |
| // Created by Zack Sheppard. | |
| // Copyright © 2020 Zack Sheppard. All rights reserved. | |
| // Available under the MIT License | |
| // | |
| import UIKit | |
| /// Conforming to this protocol and calling startAvoidingKeyboard will cause | |
| /// your view to automatically shrink to avoid the keyboard when it comes | |
| /// on screen. | |
| @objc protocol KeyboardAware { | |
| /// Implement this function for additional animation responses to the keyboard | |
| func customAnimationForNewKeyboardFrame(_ frame: CGRect) | |
| } | |
| // System static variable for the keyboard - is true if it is currently moving | |
| fileprivate var isKeyboardMoving: Bool = false | |
| /// This extension gives UIViewControllers automatic KeyboardAware ability, if you call startAvoidingKeyboard. | |
| /// Based on idea from https://stackoverflow.com/questions/45399178/ | |
| extension UIViewController: KeyboardAware { | |
| var keyboardIsAnimating: Bool { | |
| return isKeyboardMoving | |
| } | |
| /// This view controller should start resizing itself to avoid the keyboard | |
| func startAvoidingKeyboard() { | |
| NotificationCenter.default.addObserver( | |
| self, | |
| selector: #selector(handleKeyboardFrameWillChangeNotification(_:)), | |
| name: UIResponder.keyboardWillChangeFrameNotification, | |
| object: nil | |
| ) | |
| } | |
| /// This view controller should stop resizing itself to avoid the keyboard | |
| func stopAvoidingKeyboard() { | |
| NotificationCenter.default.removeObserver( | |
| self, | |
| name: UIResponder.keyboardWillChangeFrameNotification, | |
| object: nil | |
| ) | |
| self.additionalSafeAreaInsets.bottom = 0 | |
| } | |
| func customAnimationForNewKeyboardFrame(_ frame: CGRect) { | |
| // Feel free to override this to add custom handling | |
| } | |
| @objc private func handleKeyboardFrameWillChangeNotification(_ notification: Notification) { | |
| guard let userInfo = notification.userInfo, | |
| let keyboardFrame = (userInfo[UIResponder.keyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue else { | |
| isKeyboardMoving = false | |
| return | |
| } | |
| let keyboardFrameInView = view.convert(keyboardFrame, from: nil) | |
| let safeAreaFrame = view.safeAreaLayoutGuide.layoutFrame.insetBy(dx: 0, dy: -additionalSafeAreaInsets.bottom) | |
| let intersection = safeAreaFrame.intersection(keyboardFrameInView) | |
| let animationDuration: TimeInterval = (notification.userInfo?[UIResponder.keyboardAnimationDurationUserInfoKey] as? NSNumber)?.doubleValue ?? 0 | |
| let animationCurve: UIView.AnimationOptions | |
| if let animationCurveRawValue = (notification.userInfo?[UIResponder.keyboardAnimationCurveUserInfoKey] as? NSNumber)?.uintValue { | |
| animationCurve = UIView.AnimationOptions(rawValue: animationCurveRawValue) | |
| } else { | |
| animationCurve = UIView.AnimationOptions.curveEaseInOut | |
| } | |
| isKeyboardMoving = true | |
| UIView.animate(withDuration: animationDuration, delay: 0, options: animationCurve, animations: { | |
| self.additionalSafeAreaInsets.bottom = intersection.height | |
| self.customAnimationForNewKeyboardFrame(intersection) | |
| self.view.layoutIfNeeded() | |
| }, completion: { (_) in | |
| isKeyboardMoving = false | |
| }) | |
| } | |
| } |
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