124 lines
4.6 KiB
Swift
124 lines
4.6 KiB
Swift
/*
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Copyright 2019-2024 New Vector Ltd.
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SPDX-License-Identifier: AGPL-3.0-only
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Please see LICENSE in the repository root for full details.
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*/
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import Foundation
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@objcMembers
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/// Avoid keyboard overlap with scroll view content
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final class KeyboardAvoider: NSObject {
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// MARK: - Constants
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private enum KeyboardAnimation {
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static let defaultDuration: TimeInterval = 0.25
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static let defaultAnimationCurveRawValue: Int = UIView.AnimationCurve.easeInOut.rawValue
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}
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// MARK: - Properties
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weak var scrollViewContainerView: UIView?
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weak var scrollView: UIScrollView?
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// MARK: - Setup
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/// Designated initializer.
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///
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/// - Parameter scrollViewContainerView: The view that wraps the scroll view.
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/// - Parameter scrollView: The scroll view containing keyboard inputs and where content view overlap with keyboard should be avoided.
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init(scrollViewContainerView: UIView, scrollView: UIScrollView) {
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self.scrollViewContainerView = scrollViewContainerView
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self.scrollView = scrollView
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super.init()
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}
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// MARK: - Public
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/// Start keyboard avoiding
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func startAvoiding() {
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self.registerKeyboardNotifications()
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}
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/// Stop keyboard avoiding
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func stopAvoiding() {
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self.unregisterKeyboardNotifications()
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}
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// MARK: - Private
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private func registerKeyboardNotifications() {
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let notificationCenter = NotificationCenter.default
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notificationCenter.addObserver(
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self,
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selector: #selector(keyboardWillShow(notification:)),
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name: UIResponder.keyboardWillShowNotification,
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object: nil)
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notificationCenter.addObserver(
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self,
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selector: #selector(keyboardWillHide(notification:)),
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name: UIResponder.keyboardWillHideNotification,
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object: nil)
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}
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private func unregisterKeyboardNotifications() {
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NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillShowNotification, object: nil)
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NotificationCenter.default.removeObserver(self, name: UIResponder.keyboardWillHideNotification, object: nil)
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}
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@objc private func keyboardWillShow(notification: Notification) {
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guard let view = self.scrollViewContainerView, let scrollView = self.scrollView else {
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return
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}
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guard let keyboardNotification = KeyboardNotification(notification: notification),
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let keyboardFrame = keyboardNotification.keyboardFrameEnd else {
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return
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}
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let animationDuration = keyboardNotification.animationDuration ?? KeyboardAnimation.defaultDuration
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let animationOptions = keyboardNotification.animationOptions(fallbackAnimationCurveValue: KeyboardAnimation.defaultAnimationCurveRawValue)
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// Transform the keyboard's frame into our view's coordinate system
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let keyboardFrameInView = view.convert(keyboardFrame, from: nil)
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// Find how much the keyboard overlaps the scroll view
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let scrollViewBottomInset = max(scrollView.frame.maxY - keyboardFrameInView.origin.y - view.safeAreaInsets.bottom, 0)
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UIView.animate(withDuration: animationDuration,
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delay: 0.0,
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options: animationOptions, animations: {
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scrollView.contentInset.bottom = scrollViewBottomInset
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scrollView.scrollIndicatorInsets.bottom = scrollViewBottomInset
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}, completion: nil)
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}
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@objc private func keyboardWillHide(notification: Notification) {
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guard let scrollView = self.scrollView else {
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return
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}
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guard let keyboardNotification = KeyboardNotification(notification: notification) else {
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return
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}
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let animationDuration = keyboardNotification.animationDuration ?? KeyboardAnimation.defaultDuration
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let animationOptions = keyboardNotification.animationOptions(fallbackAnimationCurveValue: KeyboardAnimation.defaultAnimationCurveRawValue)
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// Reset scroll view bottom inset to zero
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let scrollViewBottomInset: CGFloat = 0.0
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UIView.animate(withDuration: animationDuration,
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delay: 0.0,
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options: animationOptions, animations: {
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scrollView.contentInset.bottom = scrollViewBottomInset
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scrollView.scrollIndicatorInsets.bottom = scrollViewBottomInset
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}, completion: nil)
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}
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}
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