Signal-iOS/Signal/src/ViewControllers/MediaGallery/MediaTileViewController.swift
Jordan Rose 4e2fe8ca69 MediaGallery: avoid full searches in favor of per-section searches
Also, share more infrastructure with the tile view.
2021-03-04 10:30:54 -08:00

836 lines
31 KiB
Swift

//
// Copyright (c) 2021 Open Whisper Systems. All rights reserved.
//
import Foundation
fileprivate extension IndexSet {
func shifted(startingAt index: Int? = nil, by amount: Int) -> IndexSet {
var result = self
result.shift(startingAt: index ?? self.first ?? 0, by: amount)
return result
}
}
@objc
public class MediaTileViewController: UICollectionViewController, MediaGalleryDelegate, UICollectionViewDelegateFlowLayout {
private var galleryDates: [GalleryDate] { return mediaGallery.sections.orderedKeys }
private let thread: TSThread
private lazy var mediaGallery: MediaGallery = {
let mediaGallery = MediaGallery(thread: thread)
mediaGallery.addDelegate(self)
return mediaGallery
}()
fileprivate let mediaTileViewLayout: MediaTileViewLayout
@objc
public init(thread: TSThread) {
self.thread = thread
let layout: MediaTileViewLayout = type(of: self).buildLayout()
self.mediaTileViewLayout = layout
super.init(collectionViewLayout: layout)
}
required public init?(coder aDecoder: NSCoder) {
notImplemented()
}
// MARK: Subviews
lazy var footerBar: UIToolbar = {
let footerBar = UIToolbar()
let footerItems = [
UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil),
deleteButton,
UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
]
footerBar.setItems(footerItems, animated: false)
return footerBar
}()
lazy var deleteButton: UIBarButtonItem = {
let deleteButton = UIBarButtonItem(barButtonSystemItem: .trash,
target: self,
action: #selector(didPressDelete),
accessibilityIdentifier: UIView.accessibilityIdentifier(in: self, name: "delete_button"))
return deleteButton
}()
// MARK: View Lifecycle Overrides
override public func viewDidLoad() {
super.viewDidLoad()
self.title = MediaStrings.allMedia
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
collectionView.register(PhotoGridViewCell.self, forCellWithReuseIdentifier: PhotoGridViewCell.reuseIdentifier)
collectionView.register(ThemeCollectionViewSectionHeader.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: ThemeCollectionViewSectionHeader.reuseIdentifier)
collectionView.register(MediaGalleryStaticHeader.self, forSupplementaryViewOfKind: UICollectionView.elementKindSectionHeader, withReuseIdentifier: MediaGalleryStaticHeader.reuseIdentifier)
collectionView.delegate = self
// feels a bit weird to have content smashed all the way to the bottom edge.
collectionView.contentInset = UIEdgeInsets(top: 0, left: 0, bottom: 20, right: 0)
self.view.addSubview(self.footerBar)
footerBar.autoPinWidthToSuperview()
footerBar.autoSetDimension(.height, toSize: kFooterBarHeight)
self.footerBarBottomConstraint = footerBar.autoPinEdge(toSuperviewEdge: .bottom, withInset: -kFooterBarHeight)
updateSelectButton()
self.mediaTileViewLayout.invalidateLayout()
applyTheme()
NotificationCenter.default.addObserver(self, selector: #selector(applyTheme), name: .ThemeDidChange, object: nil)
}
override public func viewWillAppear(_ animated: Bool) {
if mediaGallery.sections.isEmpty {
databaseStorage.uiRead { transaction in
_ = self.mediaGallery.loadEarlierSections(transaction: transaction)
}
}
self.view.layoutIfNeeded()
let lastSectionItemCount = self.collectionView(self.collectionView!,
numberOfItemsInSection: self.galleryDates.count)
// FIXME: This actually stops in the middle of the last row, but so did the old logic.
self.collectionView.scrollToItem(at: IndexPath(item: lastSectionItemCount - 1,
section: self.galleryDates.count),
at: .bottom,
animated: false)
super.viewWillAppear(animated)
}
override public func viewWillTransition(to size: CGSize,
with coordinator: UIViewControllerTransitionCoordinator) {
self.mediaTileViewLayout.invalidateLayout()
}
public override func viewWillLayoutSubviews() {
super.viewWillLayoutSubviews()
self.updateLayout()
}
// MARK: Theme
@objc func applyTheme() {
footerBar.barTintColor = Theme.navbarBackgroundColor
footerBar.tintColor = Theme.primaryIconColor
deleteButton.tintColor = Theme.primaryIconColor
collectionView.backgroundColor = Theme.backgroundColor
}
// MARK: Orientation
override public var supportedInterfaceOrientations: UIInterfaceOrientationMask {
return UIDevice.current.defaultSupportedOrienations
}
// MARK: UICollectionViewDelegate
override public func scrollViewDidScroll(_ scrollView: UIScrollView) {
self.autoLoadMoreIfNecessary()
}
override public func collectionView(_ collectionView: UICollectionView, shouldSelectItemAt indexPath: IndexPath) -> Bool {
Logger.debug("")
guard galleryDates.count > 0 else {
return false
}
switch indexPath.section {
case kLoadOlderSectionIdx, loadNewerSectionIdx:
return false
default:
return true
}
}
override public func collectionView(_ collectionView: UICollectionView, shouldDeselectItemAt indexPath: IndexPath) -> Bool {
Logger.debug("")
guard galleryDates.count > 0 else {
return false
}
switch indexPath.section {
case kLoadOlderSectionIdx, loadNewerSectionIdx:
return false
default:
return true
}
}
public override func collectionView(_ collectionView: UICollectionView, shouldHighlightItemAt indexPath: IndexPath) -> Bool {
Logger.debug("")
guard galleryDates.count > 0 else {
return false
}
switch indexPath.section {
case kLoadOlderSectionIdx, loadNewerSectionIdx:
return false
default:
return true
}
}
override public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
Logger.debug("")
guard let gridCell = self.collectionView(collectionView, cellForItemAt: indexPath) as? PhotoGridViewCell else {
owsFailDebug("galleryCell was unexpectedly nil")
return
}
guard let galleryItem = (gridCell.item as? GalleryGridCellItem)?.galleryItem else {
owsFailDebug("galleryItem was unexpectedly nil")
return
}
if isInBatchSelectMode {
updateDeleteButton()
} else {
collectionView.deselectItem(at: indexPath, animated: true)
let pageVC = MediaPageViewController(
initialMediaAttachment: galleryItem.attachmentStream,
mediaGallery: mediaGallery
)
present(pageVC, animated: true)
}
}
public override func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
Logger.debug("")
if isInBatchSelectMode {
updateDeleteButton()
}
}
// MARK: UICollectionViewDataSource
override public func numberOfSections(in collectionView: UICollectionView) -> Int {
Logger.debug("")
guard galleryDates.count > 0 else {
// empty gallery
return 1
}
// One for each galleryDate plus a "loading older" and "loading newer" section
return galleryDates.count + 2
}
override public func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection sectionIdx: Int) -> Int {
Logger.debug("\(sectionIdx)")
guard galleryDates.count > 0 else {
// empty gallery
return 0
}
if sectionIdx == kLoadOlderSectionIdx {
// load older
return 0
}
if sectionIdx == loadNewerSectionIdx {
// load more recent
return 0
}
guard let count = mediaGallery.sections[safe: sectionIdx - 1]?.value.count else {
owsFailDebug("unknown section: \(sectionIdx)")
return 0
}
return count
}
override public func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {
let defaultView = UICollectionReusableView()
guard galleryDates.count > 0 else {
guard let sectionHeader = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: MediaGalleryStaticHeader.reuseIdentifier, for: indexPath) as? MediaGalleryStaticHeader else {
owsFailDebug("unable to build section header for kLoadOlderSectionIdx")
return defaultView
}
let title = NSLocalizedString("GALLERY_TILES_EMPTY_GALLERY", comment: "Label indicating media gallery is empty")
sectionHeader.configure(title: title)
return sectionHeader
}
if kind == UICollectionView.elementKindSectionHeader {
switch indexPath.section {
case kLoadOlderSectionIdx:
guard let sectionHeader = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: MediaGalleryStaticHeader.reuseIdentifier, for: indexPath) as? MediaGalleryStaticHeader else {
owsFailDebug("unable to build section header for kLoadOlderSectionIdx")
return defaultView
}
let title = NSLocalizedString("GALLERY_TILES_LOADING_OLDER_LABEL", comment: "Label indicating loading is in progress")
sectionHeader.configure(title: title)
return sectionHeader
case loadNewerSectionIdx:
guard let sectionHeader = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: MediaGalleryStaticHeader.reuseIdentifier, for: indexPath) as? MediaGalleryStaticHeader else {
owsFailDebug("unable to build section header for kLoadOlderSectionIdx")
return defaultView
}
let title = NSLocalizedString("GALLERY_TILES_LOADING_MORE_RECENT_LABEL", comment: "Label indicating loading is in progress")
sectionHeader.configure(title: title)
return sectionHeader
default:
guard let sectionHeader = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: ThemeCollectionViewSectionHeader.reuseIdentifier, for: indexPath) as? ThemeCollectionViewSectionHeader else {
owsFailDebug("unable to build section header for indexPath: \(indexPath)")
return defaultView
}
guard let date = self.galleryDates[safe: indexPath.section - 1] else {
owsFailDebug("unknown section for indexPath: \(indexPath)")
return defaultView
}
sectionHeader.configure(title: date.localizedString)
return sectionHeader
}
}
return defaultView
}
override public func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
Logger.debug("indexPath: \(indexPath)")
let defaultCell = UICollectionViewCell()
guard galleryDates.count > 0 else {
owsFailDebug("unexpected cell for loadNewerSectionIdx")
return defaultCell
}
switch indexPath.section {
case kLoadOlderSectionIdx:
owsFailDebug("unexpected cell for kLoadOlderSectionIdx")
return defaultCell
case loadNewerSectionIdx:
owsFailDebug("unexpected cell for loadNewerSectionIdx")
return defaultCell
default:
guard let galleryItem = galleryItem(at: indexPath) else {
owsFailDebug("no message for path: \(indexPath)")
return defaultCell
}
guard let cell = self.collectionView?.dequeueReusableCell(withReuseIdentifier: PhotoGridViewCell.reuseIdentifier, for: indexPath) as? PhotoGridViewCell else {
owsFailDebug("unexpected cell for indexPath: \(indexPath)")
return defaultCell
}
let gridCellItem = GalleryGridCellItem(galleryItem: galleryItem)
cell.configure(item: gridCellItem)
return cell
}
}
override public func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
guard let photoGridViewCell = cell as? PhotoGridViewCell else {
owsFailDebug("unexpected cell: \(cell)")
return
}
photoGridViewCell.allowsMultipleSelection = collectionView.allowsMultipleSelection
}
func galleryItem(at indexPath: IndexPath) -> MediaGalleryItem? {
var underlyingPath = indexPath
underlyingPath.section -= 1
if let loadedGalleryItem = mediaGallery.galleryItem(at: underlyingPath) {
return loadedGalleryItem
}
// Only load "after" the current item in this function, to avoid shifting section indexes.
mediaGallery.ensureGalleryItemsLoaded(.after,
sectionIndex: underlyingPath.section,
itemIndex: underlyingPath.item,
amount: 50,
shouldLoadAlbumRemainder: false) { newSectionIndexes in
UIView.performWithoutAnimation {
self.collectionView.insertSections(newSectionIndexes.shifted(by: 1))
}
}
return mediaGallery.galleryItem(at: underlyingPath)
}
func updateVisibleCells() {
for cell in collectionView.visibleCells {
guard let photoGridViewCell = cell as? PhotoGridViewCell else {
owsFailDebug("unexpected cell: \(cell)")
continue
}
photoGridViewCell.allowsMultipleSelection = collectionView.allowsMultipleSelection
}
}
// MARK: UICollectionViewDelegateFlowLayout
static let kInterItemSpacing: CGFloat = 2
private class func buildLayout() -> MediaTileViewLayout {
let layout = MediaTileViewLayout()
layout.sectionInsetReference = .fromSafeArea
layout.minimumInteritemSpacing = kInterItemSpacing
layout.minimumLineSpacing = kInterItemSpacing
layout.sectionHeadersPinToVisibleBounds = true
return layout
}
func updateLayout() {
let rawSize = view.safeAreaLayoutGuide.layoutFrame.size
let containerSize = CGSize(width: floor(rawSize.width), height: floor(rawSize.height))
let kItemsPerPortraitRow = 4
let minimumViewWidth = min(containerSize.width, containerSize.height)
let approxItemWidth = minimumViewWidth / CGFloat(kItemsPerPortraitRow)
let itemCount = round(containerSize.width / approxItemWidth)
let interSpaceWidth = (itemCount - 1) * type(of: self).kInterItemSpacing
let availableWidth = max(0, containerSize.width - interSpaceWidth)
let itemWidth = floor(availableWidth / CGFloat(itemCount))
let newItemSize = CGSize(square: itemWidth)
let remainingSpace = availableWidth - (itemCount * itemWidth)
let hInset = remainingSpace / 2
if newItemSize != mediaTileViewLayout.itemSize || hInset != mediaTileViewLayout.sectionInset.left {
mediaTileViewLayout.itemSize = newItemSize
// Inset any remaining space around the outside edges to ensure all inter-item spacing is exactly equal, otherwise
// we may get slightly different gaps between rows vs. columns
mediaTileViewLayout.sectionInset = UIEdgeInsets(top: 0, leading: hInset, bottom: 0, trailing: hInset)
mediaTileViewLayout.invalidateLayout()
}
}
public func collectionView(_ collectionView: UICollectionView,
layout collectionViewLayout: UICollectionViewLayout,
referenceSizeForHeaderInSection section: Int) -> CGSize {
let kMonthHeaderSize: CGSize = CGSize(width: 0, height: 50)
let kStaticHeaderSize: CGSize = CGSize(width: 0, height: 100)
guard galleryDates.count > 0 else {
return kStaticHeaderSize
}
switch section {
case kLoadOlderSectionIdx:
// Show "loading older..." iff there is still older data to be fetched
return mediaGallery.hasFetchedOldest ? CGSize.zero : kStaticHeaderSize
case loadNewerSectionIdx:
// Show "loading newer..." iff there is still more recent data to be fetched
return mediaGallery.hasFetchedMostRecent ? CGSize.zero : kStaticHeaderSize
default:
return kMonthHeaderSize
}
}
// MARK: Batch Selection
var isInBatchSelectMode = false {
didSet {
let didChange = isInBatchSelectMode != oldValue
if didChange {
collectionView!.allowsMultipleSelection = isInBatchSelectMode
updateVisibleCells()
updateSelectButton()
updateDeleteButton()
}
}
}
func updateDeleteButton() {
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
if let count = collectionView.indexPathsForSelectedItems?.count, count > 0 {
self.deleteButton.isEnabled = true
} else {
self.deleteButton.isEnabled = false
}
}
func updateSelectButton() {
if isInBatchSelectMode {
self.navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .cancel, target: self, action: #selector(didCancelSelect),
accessibilityIdentifier: UIView.accessibilityIdentifier(in: self, name: "cancel_select_button"))
} else {
self.navigationItem.rightBarButtonItem = UIBarButtonItem(title: NSLocalizedString("BUTTON_SELECT", comment: "Button text to enable batch selection mode"),
style: .plain,
target: self,
action: #selector(didTapSelect),
accessibilityIdentifier: UIView.accessibilityIdentifier(in: self, name: "select_button"))
}
}
@objc
func didTapSelect(_ sender: Any) {
isInBatchSelectMode = true
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
// show toolbar
UIView.animate(withDuration: 0.1, delay: 0, options: .curveEaseInOut, animations: {
NSLayoutConstraint.deactivate([self.footerBarBottomConstraint])
self.footerBarBottomConstraint = self.footerBar.autoPin(toBottomLayoutGuideOf: self, withInset: 0)
self.footerBar.superview?.layoutIfNeeded()
// ensure toolbar doesn't cover bottom row.
collectionView.contentInset.bottom += self.kFooterBarHeight
}, completion: nil)
// disabled until at least one item is selected
self.deleteButton.isEnabled = false
// Don't allow the user to leave mid-selection, so they realized they have
// to cancel (lose) their selection if they leave.
self.navigationItem.hidesBackButton = true
}
@objc
func didCancelSelect(_ sender: Any) {
endSelectMode()
}
func endSelectMode() {
isInBatchSelectMode = false
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
// hide toolbar
UIView.animate(withDuration: 0.1, delay: 0, options: .curveEaseInOut, animations: {
NSLayoutConstraint.deactivate([self.footerBarBottomConstraint])
self.footerBarBottomConstraint = self.footerBar.autoPinEdge(toSuperviewEdge: .bottom, withInset: -self.kFooterBarHeight)
self.footerBar.superview?.layoutIfNeeded()
// undo "ensure toolbar doesn't cover bottom row."
collectionView.contentInset.bottom -= self.kFooterBarHeight
}, completion: nil)
self.navigationItem.hidesBackButton = false
// deselect any selected
collectionView.indexPathsForSelectedItems?.forEach { collectionView.deselectItem(at: $0, animated: false)}
}
@objc
func didPressDelete(_ sender: Any) {
Logger.debug("")
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
guard let indexPaths = collectionView.indexPathsForSelectedItems else {
owsFailDebug("indexPaths was unexpectedly nil")
return
}
let items: [MediaGalleryItem] = indexPaths.compactMap { return self.galleryItem(at: $0) }
guard items.count == indexPaths.count else {
owsFailDebug("trying to delete an item that never loaded")
return
}
let confirmationTitle: String = {
if indexPaths.count == 1 {
return NSLocalizedString("MEDIA_GALLERY_DELETE_SINGLE_MESSAGE", comment: "Confirmation button text to delete selected media message from the gallery")
} else {
let format = NSLocalizedString("MEDIA_GALLERY_DELETE_MULTIPLE_MESSAGES_FORMAT", comment: "Confirmation button text to delete selected media from the gallery, embeds {{number of messages}}")
return String(format: format, indexPaths.count)
}
}()
let deleteAction = ActionSheetAction(title: confirmationTitle, style: .destructive) { _ in
let galleryIndexPaths = indexPaths.map { IndexPath(item: $0.item, section: $0.section - 1) }
self.mediaGallery.delete(items: items, atIndexPaths: galleryIndexPaths, initiatedBy: self, deleteFromDB: true)
self.endSelectMode()
}
let actionSheet = ActionSheetController(title: nil, message: nil)
actionSheet.addAction(deleteAction)
actionSheet.addAction(OWSActionSheets.cancelAction)
presentActionSheet(actionSheet)
}
var footerBarBottomConstraint: NSLayoutConstraint!
let kFooterBarHeight: CGFloat = 40
// MARK: MediaGalleryDelegate
func mediaGallery(_ mediaGallery: MediaGallery, willDelete items: [MediaGalleryItem], initiatedBy: AnyObject) {
Logger.debug("")
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
// We've got to lay out the collectionView before any changes are made to the date source
// otherwise we'll fail when we try to remove the deleted sections/rows
collectionView.layoutIfNeeded()
}
func mediaGallery(_ mediaGallery: MediaGallery, deletedSections: IndexSet, deletedItems: [IndexPath]) {
Logger.debug("with deletedSections: \(deletedSections) deletedItems: \(deletedItems)")
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
guard mediaGallery.galleryItemCount > 0 else {
// Show Empty
self.collectionView?.reloadData()
return
}
collectionView.performBatchUpdates({
collectionView.deleteSections(deletedSections.shifted(by: 1))
collectionView.deleteItems(at: deletedItems.map { IndexPath(item: $0.item, section: $0.section + 1) })
})
}
func mediaGallery(_ mediaGallery: MediaGallery, didReloadItemsInSections sections: IndexSet) {
collectionView.reloadSections(sections.shifted(by: 1))
}
// MARK: Lazy Loading
var isFetchingMoreData: Bool = false
let kLoadOlderSectionIdx = 0
var loadNewerSectionIdx: Int {
return galleryDates.count + 1
}
public func autoLoadMoreIfNecessary() {
let kEdgeThreshold: CGFloat = 800
guard let collectionView = self.collectionView else {
owsFailDebug("collectionView was unexpectedly nil")
return
}
let contentOffsetY = collectionView.contentOffset.y
let oldContentHeight = collectionView.contentSize.height
let direction: GalleryDirection
if contentOffsetY < kEdgeThreshold {
// Near the top, load older content
guard !mediaGallery.hasFetchedOldest else {
return
}
mediaTileViewLayout.recordContentSizeBeforeInsertingToTop()
direction = .before
} else if oldContentHeight - contentOffsetY < kEdgeThreshold {
// Near the bottom, load newer content
guard !mediaGallery.hasFetchedMostRecent else {
return
}
direction = .after
} else {
return
}
guard !isFetchingMoreData else {
Logger.debug("already fetching more data")
return
}
isFetchingMoreData = true
UIView.performWithoutAnimation {
collectionView.performBatchUpdates({
databaseStorage.uiRead { transaction in
let newSections: Range<Int>
switch direction {
case .before:
newSections = 0..<mediaGallery.loadEarlierSections(transaction: transaction)
case .after:
let newSectionCount = mediaGallery.loadLaterSections(transaction: transaction)
newSections = (mediaGallery.sections.count - newSectionCount)..<mediaGallery.sections.count
case .around:
preconditionFailure() // unused
}
Logger.debug("found new sections: \(newSections)")
collectionView.insertSections(IndexSet(newSections).shifted(by: 1))
}
}, completion: { finished in
Logger.debug("performBatchUpdates finished: \(finished)")
self.isFetchingMoreData = false
})
}
}
}
extension MediaTileViewController: MediaPresentationContextProvider {
func mediaPresentationContext(item: Media, in coordinateSpace: UICoordinateSpace) -> MediaPresentationContext? {
// First time presentation can occur before layout.
view.layoutIfNeeded()
guard case let .gallery(galleryItem) = item else {
owsFailDebug("Unexpected media type")
return nil
}
guard let underlyingPath = mediaGallery.indexPath(for: galleryItem) else {
owsFailDebug("galleryItemIndexPath was unexpectedly nil")
return nil
}
var indexPath = underlyingPath
indexPath.section += 1
guard let visibleIndex = collectionView.indexPathsForVisibleItems.firstIndex(of: indexPath) else {
Logger.debug("visibleIndex was nil, swiped to offscreen gallery item")
return nil
}
guard let cell = collectionView.visibleCells[safe: visibleIndex] as? PhotoGridViewCell else {
owsFailDebug("cell was unexpectedly nil")
return nil
}
let mediaView = cell.imageView
guard let mediaSuperview = mediaView.superview else {
owsFailDebug("mediaSuperview was unexpectedly nil")
return nil
}
let presentationFrame = coordinateSpace.convert(mediaView.frame, from: mediaSuperview)
return MediaPresentationContext(mediaView: mediaView, presentationFrame: presentationFrame, cornerRadius: 0)
}
func snapshotOverlayView(in coordinateSpace: UICoordinateSpace) -> (UIView, CGRect)? {
return nil
}
}
// MARK: - Private Helper Classes
// Accomodates remaining scrolled to the same "apparent" position when new content is inserted
// into the top of a collectionView. There are multiple ways to solve this problem, but this
// is the only one which avoided a perceptible flicker.
private class MediaTileViewLayout: UICollectionViewFlowLayout {
private var contentSizeBeforeInsertingToTop: CGSize?
func recordContentSizeBeforeInsertingToTop() {
contentSizeBeforeInsertingToTop = collectionViewContentSize
}
override public func prepare() {
super.prepare()
if let collectionView = collectionView, let oldContentSize = contentSizeBeforeInsertingToTop {
let newContentSize = collectionViewContentSize
collectionView.contentOffset.y += newContentSize.height - oldContentSize.height
contentSizeBeforeInsertingToTop = nil
}
}
}
private class MediaGalleryStaticHeader: UICollectionViewCell {
static let reuseIdentifier = "MediaGalleryStaticHeader"
let label = UILabel()
override init(frame: CGRect) {
super.init(frame: frame)
label.textColor = Theme.primaryTextColor
label.font = UIFont.ows_dynamicTypeBody
addSubview(label)
label.textAlignment = .center
label.numberOfLines = 0
label.autoPinEdgesToSuperviewMargins()
}
@available(*, unavailable, message: "Unimplemented")
required public init?(coder aDecoder: NSCoder) {
notImplemented()
}
public func configure(title: String) {
label.text = title
}
public override func prepareForReuse() {
label.text = nil
label.textColor = Theme.primaryTextColor
label.font = UIFont.ows_dynamicTypeBody
}
}
class GalleryGridCellItem: PhotoGridItem {
let galleryItem: MediaGalleryItem
init(galleryItem: MediaGalleryItem) {
self.galleryItem = galleryItem
}
var type: PhotoGridItemType {
if galleryItem.isVideo {
return .video
} else if galleryItem.isAnimated {
return .animated
} else {
return .photo
}
}
func asyncThumbnail(completion: @escaping (UIImage?) -> Void) -> UIImage? {
return galleryItem.thumbnailImage(async: completion)
}
}