Signal-iOS/Signal/src/ViewControllers/InteractiveSheetViewController.swift
2021-08-19 17:07:15 -03:00

333 lines
13 KiB
Swift

//
// Copyright (c) 2021 Open Whisper Systems. All rights reserved.
//
import Foundation
public class InteractiveSheetViewController: OWSViewController {
public let contentView = UIView()
public var interactiveScrollViews: [UIScrollView] { [] }
public weak var externalBackdropView: UIView?
private lazy var _internalBackdropView = UIView()
public var backdropView: UIView? { externalBackdropView ?? _internalBackdropView }
public var maxWidth: CGFloat { 512 }
public var minHeight: CGFloat { 346 }
public var allowsInteractiveDismisssal: Bool { true }
public var renderExternalHandle: Bool { true }
private lazy var handle = UIView()
public required override init() {
super.init()
modalPresentationStyle = .custom
transitioningDelegate = self
}
public func willDismissInteractively() {}
// MARK: -
public override func loadView() {
view = UIView()
view.backgroundColor = .clear
view.addSubview(contentView)
contentView.autoPinEdge(toSuperviewEdge: .bottom)
contentView.autoHCenterInSuperview()
contentView.autoMatch(.height, to: .height, of: view, withOffset: 0, relation: .lessThanOrEqual)
contentView.backgroundColor = Theme.actionSheetBackgroundColor
// Prefer to be full width, but don't exceed the maximum width
contentView.autoSetDimension(.width, toSize: maxWidth, relation: .lessThanOrEqual)
NSLayoutConstraint.autoSetPriority(.defaultHigh) {
contentView.autoPinWidthToSuperview()
}
contentView.layer.cornerRadius = 16
contentView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMinYCorner]
contentView.layer.masksToBounds = true
// Support tapping the backdrop to cancel the sheet.
let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didTapBackdrop(_:)))
tapGestureRecognizer.delegate = self
view.addGestureRecognizer(tapGestureRecognizer)
// Setup handle for interactive dismissal / resizing
setupInteractiveSizing()
}
@objc func didTapBackdrop(_ sender: UITapGestureRecognizer) {
guard allowsInteractiveDismisssal else { return }
willDismissInteractively()
dismiss(animated: true)
}
// MARK: - Resize / Interactive Dismiss
var heightConstraint: NSLayoutConstraint?
var minimizedHeight: CGFloat {
return min(maximizedHeight, minHeight)
}
var maximizedHeight: CGFloat {
return CurrentAppContext().frame.height - (view.safeAreaInsets.top + 32)
}
public func maximizeHeight() {
heightConstraint?.constant = maximizedHeight
view.layoutIfNeeded()
}
let maxAnimationDuration: TimeInterval = 0.2
private var startingHeight: CGFloat?
private var startingTranslation: CGFloat?
private func setupInteractiveSizing() {
heightConstraint = contentView.autoSetDimension(.height, toSize: minimizedHeight)
// Create a pan gesture to handle when the user interacts with the
// view outside of any scroll views we want to follow.
let panGestureRecognizer = DirectionalPanGestureRecognizer(direction: .vertical, target: self, action: #selector(handlePan))
view.addGestureRecognizer(panGestureRecognizer)
panGestureRecognizer.delegate = self
// We also want to handle the pan gesture for all of the scroll
// views, so we can do a nice scroll to dismiss gesture, and
// so we can transfer any initial scrolling into maximizing
// the view.
interactiveScrollViews.forEach { $0.panGestureRecognizer.addTarget(self, action: #selector(handlePan)) }
if renderExternalHandle {
handle.backgroundColor = .ows_whiteAlpha80
handle.autoSetDimensions(to: CGSize(width: 56, height: 5))
handle.layer.cornerRadius = 5 / 2
view.addSubview(handle)
handle.autoHCenterInSuperview()
handle.autoPinEdge(.bottom, to: .top, of: contentView, withOffset: -8)
}
}
@objc
private func handlePan(_ sender: UIPanGestureRecognizer) {
let panningScrollView = interactiveScrollViews.first { $0.panGestureRecognizer == sender }
switch sender.state {
case .began, .changed:
guard beginInteractiveTransitionIfNecessary(sender),
let startingHeight = startingHeight,
let startingTranslation = startingTranslation else {
return resetInteractiveTransition(panningScrollView: panningScrollView)
}
// We're in an interactive transition, so don't let the scrollView scroll.
if let panningScrollView = panningScrollView {
panningScrollView.contentOffset.y = 0
panningScrollView.showsVerticalScrollIndicator = false
}
// We may have panned some distance if we were scrolling before we started
// this interactive transition. Offset the translation we use to move the
// view by whatever the translation was when we started the interactive
// portion of the gesture.
let translation = sender.translation(in: view).y - startingTranslation
var newHeight = startingHeight - translation
if newHeight > maximizedHeight {
newHeight = maximizedHeight
}
// If the height is decreasing, adjust the relevant view's proporitionally
if newHeight < startingHeight {
backdropView?.alpha = 1 - (startingHeight - newHeight) / startingHeight
}
// Update our height to reflect the new position
heightConstraint?.constant = newHeight
view.layoutIfNeeded()
case .ended, .cancelled, .failed:
guard let startingHeight = startingHeight else { break }
let dismissThreshold = startingHeight * 0.5
let growThreshold = startingHeight * 1.5
let velocityThreshold: CGFloat = 500
let currentHeight = contentView.height
let currentVelocity = sender.velocity(in: view).y
enum CompletionState { case growing, dismissing, cancelling }
let completionState: CompletionState
if abs(currentVelocity) >= velocityThreshold {
if currentVelocity < 0 {
completionState = .growing
} else {
completionState = allowsInteractiveDismisssal ? .dismissing : .cancelling
}
} else if currentHeight >= growThreshold {
completionState = .growing
} else if currentHeight <= dismissThreshold, allowsInteractiveDismisssal {
completionState = .dismissing
} else {
completionState = .cancelling
}
let finalHeight: CGFloat
switch completionState {
case .dismissing:
finalHeight = 0
case .growing:
finalHeight = maximizedHeight
case .cancelling:
finalHeight = startingHeight
}
let remainingDistance = finalHeight - currentHeight
// Calculate the time to complete the animation if we want to preserve
// the user's velocity. If this time is too slow (e.g. the user was scrolling
// very slowly) we'll default to `maxAnimationDuration`
let remainingTime = TimeInterval(abs(remainingDistance / currentVelocity))
UIView.animate(withDuration: min(remainingTime, maxAnimationDuration), delay: 0, options: .curveEaseOut, animations: {
if remainingDistance < 0 {
self.contentView.frame.origin.y -= remainingDistance
self.handle.frame.origin.y -= remainingDistance
} else {
self.heightConstraint?.constant = finalHeight
self.view.layoutIfNeeded()
}
self.backdropView?.alpha = completionState == .dismissing ? 0 : 1
}) { _ in
owsAssertDebug(completionState != .dismissing || self.allowsInteractiveDismisssal)
self.heightConstraint?.constant = finalHeight
self.view.layoutIfNeeded()
if completionState == .dismissing {
self.willDismissInteractively()
self.dismiss(animated: true, completion: nil)
}
}
resetInteractiveTransition(panningScrollView: panningScrollView)
default:
resetInteractiveTransition(panningScrollView: panningScrollView)
backdropView?.alpha = 1
guard let startingHeight = startingHeight else { break }
heightConstraint?.constant = startingHeight
}
}
private func beginInteractiveTransitionIfNecessary(_ sender: UIPanGestureRecognizer) -> Bool {
let panningScrollView = interactiveScrollViews.first { $0.panGestureRecognizer == sender }
// If we're at the top of the scrollView, the the view is not
// currently maximized, or we're panning outside of the scroll
// view we want to do an interactive transition.
guard (panningScrollView != nil && panningScrollView!.contentOffset.y <= 0)
|| contentView.height < maximizedHeight
|| panningScrollView == nil else { return false }
if startingTranslation == nil {
startingTranslation = sender.translation(in: view).y
}
if startingHeight == nil {
startingHeight = contentView.height
}
return true
}
private func resetInteractiveTransition(panningScrollView: UIScrollView?) {
startingTranslation = nil
startingHeight = nil
panningScrollView?.showsVerticalScrollIndicator = true
}
}
// MARK: -
extension InteractiveSheetViewController: UIGestureRecognizerDelegate {
public func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
switch gestureRecognizer {
case is UITapGestureRecognizer:
let point = gestureRecognizer.location(in: view)
guard !contentView.frame.contains(point) else { return false }
return true
default:
return true
}
}
public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRequireFailureOf otherGestureRecognizer: UIGestureRecognizer) -> Bool {
switch gestureRecognizer {
case is UIPanGestureRecognizer:
return interactiveScrollViews.map { $0.panGestureRecognizer }.contains(otherGestureRecognizer)
default:
return false
}
}
}
// MARK: -
private class InteractiveSheetAnimationController: UIPresentationController {
var backdropView: UIView? {
guard let vc = presentedViewController as? InteractiveSheetViewController else { return nil }
return vc.backdropView
}
var isUsingExternalBackdropView: Bool {
guard let vc = presentedViewController as? InteractiveSheetViewController else { return false }
return vc.externalBackdropView != nil
}
override init(presentedViewController: UIViewController, presenting presentingViewController: UIViewController?) {
super.init(presentedViewController: presentedViewController, presenting: presentingViewController)
backdropView?.backgroundColor = Theme.backdropColor
}
override func presentationTransitionWillBegin() {
if !isUsingExternalBackdropView, let containerView = containerView, let backdropView = backdropView {
backdropView.alpha = 0
containerView.addSubview(backdropView)
backdropView.autoPinEdgesToSuperviewEdges()
containerView.layoutIfNeeded()
}
presentedViewController.transitionCoordinator?.animate(alongsideTransition: { _ in
self.backdropView?.alpha = 1
}, completion: nil)
}
override func dismissalTransitionWillBegin() {
presentedViewController.transitionCoordinator?.animate(alongsideTransition: { _ in
self.backdropView?.alpha = 0
}, completion: { _ in
self.backdropView?.removeFromSuperview()
})
}
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
super.viewWillTransition(to: size, with: coordinator)
guard let presentedView = presentedView else { return }
coordinator.animate(alongsideTransition: { _ in
presentedView.frame = self.frameOfPresentedViewInContainerView
presentedView.layoutIfNeeded()
}, completion: nil)
}
}
extension InteractiveSheetViewController: UIViewControllerTransitioningDelegate {
public func presentationController(forPresented presented: UIViewController, presenting: UIViewController?, source: UIViewController) -> UIPresentationController? {
return InteractiveSheetAnimationController(presentedViewController: presented, presenting: presenting)
}
}