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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
import Common
import Foundation
import UIKit
/// Protocol followed by child of the bottom sheet, which holds the content shown in the bottom sheet.
public protocol BottomSheetChild: UIViewController {
/// Tells the child that the bottom sheet will get dismissed
func willDismiss()
}
/// Protocol followed by the bottom sheet view controller. Gives the possibility to dismiss the bottom sheet.
public protocol BottomSheetDismissProtocol {
func dismissSheetViewController(completion: (() -> Void)?)
}
public class BottomSheetViewController: UIViewController,
BottomSheetDismissProtocol,
Themeable,
UIGestureRecognizerDelegate {
private struct UX {
static let minVisibleTopSpace: CGFloat = 40
static let closeButtonTopTrailingSpace: CGFloat = 16
static let initialSpringVelocity: CGFloat = 1
static let springWithDamping = 0.7
static let animationDuration = 0.5
}
public var notificationCenter: NotificationProtocol
public var themeManager: ThemeManager
public var themeObserver: NSObjectProtocol?
private let viewModel: BottomSheetViewModel
private var useDimmedBackground: Bool
private let childViewController: BottomSheetChild
// Views
private lazy var scrollView: FadeScrollView = .build { scrollView in
scrollView.showsHorizontalScrollIndicator = false
scrollView.contentInsetAdjustmentBehavior = .never
}
private lazy var topTapView: UIView = .build { view in
view.backgroundColor = .clear
}
private lazy var dimmedBackgroundView: UIView = .build { view in
view.backgroundColor = .clear
}
private lazy var closeButton: CloseButton = .build { button in
button.addTarget(self, action: #selector(self.closeTapped), for: .touchUpInside)
}
private lazy var sheetView: UIView = .build { _ in }
private lazy var contentView: UIView = .build { _ in }
private lazy var scrollContentView: UIView = .build { _ in }
private var contentViewBottomConstraint: NSLayoutConstraint!
private var viewTranslation = CGPoint(x: 0, y: 0)
private let windowUUID: WindowUUID
// MARK: Init
public init(viewModel: BottomSheetViewModel,
childViewController: BottomSheetChild,
usingDimmedBackground: Bool = false,
windowUUID: WindowUUID,
notificationCenter: NotificationProtocol = NotificationCenter.default,
themeManager: ThemeManager = AppContainer.shared.resolve()) {
self.viewModel = viewModel
self.childViewController = childViewController
self.notificationCenter = notificationCenter
self.themeManager = themeManager
self.useDimmedBackground = usingDimmedBackground
self.windowUUID = windowUUID
super.init(nibName: nil, bundle: nil)
modalPresentationStyle = .overFullScreen
modalTransitionStyle = .crossDissolve
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
// MARK: View lifecycle
override public func viewDidLoad() {
super.viewDidLoad()
sheetView.alpha = 1
setupChildViewController()
let closeButtonViewModel = CloseButtonViewModel(a11yLabel: viewModel.closeButtonA11yLabel,
a11yIdentifier: "a11yCloseButton")
closeButton.configure(viewModel: closeButtonViewModel)
let gesture = UIPanGestureRecognizer(target: self, action: #selector(panGesture))
contentView.addGestureRecognizer(gesture)
gesture.delegate = self
listenForThemeChange(view)
setupView()
contentViewBottomConstraint.constant = childViewController.view.frame.height
view.layoutIfNeeded()
}
override public func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
applyTheme()
}
override public func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
contentViewBottomConstraint.constant = 0
UIView.animate(withDuration: viewModel.animationTransitionDuration) {
self.view.backgroundColor = self.viewModel.backgroundColor
self.view.layoutIfNeeded()
}
}
override public func viewDidLayoutSubviews() {
super.viewDidLayoutSubviews()
contentView.clipsToBounds = true
contentView.layer.cornerRadius = viewModel.cornerRadius
contentView.layer.maskedCorners = [.layerMaxXMinYCorner, .layerMinXMinYCorner]
sheetView.layer.backgroundColor = UIColor.clear.cgColor
sheetView.layer.shadowColor = UIColor.black.cgColor
sheetView.layer.shadowOffset = CGSize(width: 0, height: -5.0)
sheetView.layer.shadowRadius = 20.0
sheetView.layer.shadowPath = UIBezierPath(roundedRect: sheetView.bounds,
cornerRadius: viewModel.cornerRadius).cgPath
}
// MARK: - Theme
public func applyTheme() {
contentView.backgroundColor = themeManager.getCurrentTheme(for: windowUUID).colors.layer1
sheetView.layer.shadowOpacity = viewModel.shadowOpacity
if useDimmedBackground {
dimmedBackgroundView.alpha = 0.4
dimmedBackgroundView.backgroundColor = .black
}
}
public var currentWindowUUID: WindowUUID? {
return windowUUID
}
// MARK: - UIGestureRecognizerDelegate
public func gestureRecognizer(
_ gestureRecognizer: UIGestureRecognizer,
shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer
) -> Bool {
return false
}
// MARK: - Private
private func setupView() {
if viewModel.shouldDismissForTapOutside {
topTapView.addGestureRecognizer(UITapGestureRecognizer(target: self,
action: #selector(self.closeTapped)))
}
scrollView.addSubview(scrollContentView)
sheetView.addSubview(contentView)
contentView.addSubviews(closeButton, scrollView)
view.addSubviews(dimmedBackgroundView, topTapView, sheetView)
view.accessibilityElements = [closeButton, sheetView]
contentViewBottomConstraint = sheetView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
let scrollViewHeightConstraint = scrollView.heightAnchor.constraint(
greaterThanOrEqualTo: scrollContentView.heightAnchor)
NSLayoutConstraint.activate([
topTapView.topAnchor.constraint(equalTo: view.topAnchor),
topTapView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
topTapView.bottomAnchor.constraint(equalTo: sheetView.topAnchor, constant: viewModel.cornerRadius),
topTapView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
dimmedBackgroundView.topAnchor.constraint(equalTo: view.topAnchor),
dimmedBackgroundView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
dimmedBackgroundView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
dimmedBackgroundView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
sheetView.topAnchor.constraint(greaterThanOrEqualTo: view.topAnchor,
constant: BottomSheetViewController.UX.minVisibleTopSpace),
sheetView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
contentViewBottomConstraint,
sheetView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
contentView.topAnchor.constraint(equalTo: sheetView.topAnchor),
contentView.leadingAnchor.constraint(equalTo: sheetView.leadingAnchor),
contentView.bottomAnchor.constraint(equalTo: sheetView.bottomAnchor),
contentView.trailingAnchor.constraint(equalTo: sheetView.trailingAnchor),
closeButton.topAnchor.constraint(equalTo: contentView.topAnchor,
constant: BottomSheetViewController.UX.closeButtonTopTrailingSpace),
closeButton.trailingAnchor.constraint(equalTo: contentView.safeAreaLayoutGuide.trailingAnchor,
constant: -BottomSheetViewController.UX.closeButtonTopTrailingSpace),
scrollContentView.topAnchor.constraint(equalTo: scrollView.contentLayoutGuide.topAnchor),
scrollContentView.bottomAnchor.constraint(equalTo: scrollView.contentLayoutGuide.bottomAnchor),
scrollContentView.leadingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.leadingAnchor),
scrollContentView.trailingAnchor.constraint(equalTo: scrollView.contentLayoutGuide.trailingAnchor),
scrollContentView.widthAnchor.constraint(equalTo: scrollView.frameLayoutGuide.widthAnchor),
scrollView.topAnchor.constraint(equalTo: contentView.topAnchor),
scrollView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
scrollView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
scrollView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
scrollViewHeightConstraint
])
scrollViewHeightConstraint.priority = .defaultLow
contentView.bringSubviewToFront(closeButton)
}
private func setupChildViewController() {
addChild(childViewController)
scrollContentView.addSubview(childViewController.view)
childViewController.didMove(toParent: self)
guard let childSuperView = childViewController.view.superview else { return }
NSLayoutConstraint.activate([
childViewController.view.bottomAnchor.constraint(equalTo: childSuperView.bottomAnchor),
childViewController.view.topAnchor.constraint(equalTo: childSuperView.topAnchor),
childViewController.view.leftAnchor.constraint(equalTo: childSuperView.leftAnchor),
childViewController.view.rightAnchor.constraint(equalTo: childSuperView.rightAnchor)
])
childViewController.view.translatesAutoresizingMaskIntoConstraints = false
}
@objc
private func panGesture(_ recognizer: UIPanGestureRecognizer) {
switch recognizer.state {
case .changed:
viewTranslation = recognizer.translation(in: view)
// do not allow swiping up
guard viewTranslation.y > 0 else { return }
UIView.animate(withDuration: UX.animationDuration,
delay: 0,
usingSpringWithDamping: UX.springWithDamping,
initialSpringVelocity: UX.initialSpringVelocity,
options: .curveEaseOut,
animations: {
self.sheetView.transform = CGAffineTransform(translationX: 0, y: self.viewTranslation.y)
})
case .ended:
if viewTranslation.y < 200 {
UIView.animate(withDuration: UX.animationDuration,
delay: 0,
usingSpringWithDamping: UX.springWithDamping,
initialSpringVelocity: UX.initialSpringVelocity,
options: .curveEaseOut,
animations: {
self.sheetView.transform = .identity
})
} else {
dismissSheetViewController()
}
default:
break
}
}
@objc
private func closeTapped() {
dismissSheetViewController()
}
// MARK: - BottomSheetDismissProtocol
public func dismissSheetViewController(completion: (() -> Void)? = nil) {
childViewController.willDismiss()
contentViewBottomConstraint.constant = childViewController.view.frame.height
UIView.animate(
withDuration: viewModel.animationTransitionDuration,
animations: {
self.view.layoutIfNeeded()
self.view.backgroundColor = .clear
}, completion: { _ in
self.dismiss(animated: false, completion: completion)
}
)
}
}