/***************************************************************************** * ButtonBarView.Swift * VLC for iOS ***************************************************************************** * Copyright (c) 2018 VideoLAN. All rights reserved. * $Id$ * * Authors: Carola Nitz * * Refer to the COPYING file of the official project for license. *****************************************************************************/ import Foundation open class ButtonBarView: UICollectionView { open var selectedBar: UIView! open var separatorView: UIView! internal let selectedBarHeight: CGFloat = 4 internal let separatorHeight: CGFloat = 1.5 var selectedIndex = 0 @available(*, unavailable, message: "use init(frame:)") required public init?(coder aDecoder: NSCoder) { fatalError() } public override init(frame: CGRect, collectionViewLayout layout: UICollectionViewLayout) { super.init(frame: frame, collectionViewLayout: layout) setup() NotificationCenter.default.addObserver(self, selector: #selector(updateTheme), name: .VLCThemeDidChangeNotification, object: nil) } func setup() { scrollsToTop = false showsHorizontalScrollIndicator = false separatorView = UIView(frame: CGRect(x: 0, y: self.frame.size.height - separatorHeight, width: self.frame.size.width, height: separatorHeight)) addSubview(separatorView) selectedBar = UIView(frame: CGRect(x: 0, y: self.frame.size.height - CGFloat(self.selectedBarHeight), width: 0, height: CGFloat(self.selectedBarHeight))) addSubview(selectedBar) updateTheme() } @objc func updateTheme() { backgroundColor = PresentationTheme.current.colors.background selectedBar.backgroundColor = PresentationTheme.current.colors.orangeUI separatorView.backgroundColor = PresentationTheme.current.colors.mediaCategorySeparatorColor } open func moveTo(index: Int, animated: Bool, swipeDirection: SwipeDirection, pagerScroll: PagerScroll) { selectedIndex = index updateSubviewPositions(animated, swipeDirection: swipeDirection, pagerScroll: pagerScroll) } open func move(fromIndex: Int, toIndex: Int, progressPercentage: CGFloat, pagerScroll: PagerScroll) { selectedIndex = progressPercentage > 0.5 ? toIndex : fromIndex let fromFrame = layoutAttributesForItem(at: IndexPath(item: fromIndex, section: 0))!.frame let numberOfItems = dataSource!.collectionView(self, numberOfItemsInSection: 0) var toFrame: CGRect if toIndex < 0 || toIndex > numberOfItems - 1 { if toIndex < 0 { let cellAtts = layoutAttributesForItem(at: IndexPath(item: 0, section: 0)) toFrame = cellAtts!.frame.offsetBy(dx: -cellAtts!.frame.size.width, dy: 0) } else { let cellAtts = layoutAttributesForItem(at: IndexPath(item: (numberOfItems - 1), section: 0)) toFrame = cellAtts!.frame.offsetBy(dx: cellAtts!.frame.size.width, dy: 0) } } else { toFrame = layoutAttributesForItem(at: IndexPath(item: toIndex, section: 0))!.frame } var targetFrame = fromFrame targetFrame.size.height = selectedBar.frame.size.height targetFrame.size.width += (toFrame.size.width - fromFrame.size.width) * progressPercentage targetFrame.origin.x += (toFrame.origin.x - fromFrame.origin.x) * progressPercentage selectedBar.frame = CGRect(x: targetFrame.origin.x, y: selectedBar.frame.origin.y, width: targetFrame.size.width, height: selectedBar.frame.size.height) var targetContentOffset: CGFloat = 0.0 if contentSize.width > frame.size.width { let toContentOffset = contentOffsetForCell(withFrame: toFrame, andIndex: toIndex) let fromContentOffset = contentOffsetForCell(withFrame: fromFrame, andIndex: fromIndex) targetContentOffset = fromContentOffset + ((toContentOffset - fromContentOffset) * progressPercentage) } setContentOffset(CGPoint(x: targetContentOffset, y: 0), animated: false) } open func updateSubviewPositions(_ animated: Bool, swipeDirection: SwipeDirection, pagerScroll: PagerScroll) { var selectedBarFrame = selectedBar.frame let selectedCellIndexPath = IndexPath(item: selectedIndex, section: 0) let attributes = layoutAttributesForItem(at: selectedCellIndexPath) let selectedCellFrame = attributes!.frame updateContentOffset(animated: animated, pagerScroll: pagerScroll, toFrame: selectedCellFrame, toIndex: (selectedCellIndexPath as NSIndexPath).row) selectedBarFrame.size.width = selectedCellFrame.size.width selectedBarFrame.origin.x = selectedCellFrame.origin.x if animated { UIView.animate(withDuration: 0.3, animations: { [weak self] in if let strongSelf = self { strongSelf.selectedBar.frame = selectedBarFrame strongSelf.separatorView.frame = CGRect(x: 0, y: strongSelf.frame.size.height - strongSelf.separatorHeight, width: strongSelf.frame.size.width, height: strongSelf.separatorHeight) } }) } else { selectedBar.frame = selectedBarFrame separatorView.frame = CGRect(x: 0, y: frame.size.height - separatorHeight, width: frame.size.width, height: separatorHeight) } } // MARK: - Helpers private func updateContentOffset(animated: Bool, pagerScroll: PagerScroll, toFrame: CGRect, toIndex: Int) { guard pagerScroll != .no || (pagerScroll != .scrollOnlyIfOutOfScreen && (toFrame.origin.x < contentOffset.x || toFrame.origin.x >= (contentOffset.x + frame.size.width - contentInset.left))) else { return } let targetContentOffset = contentSize.width > frame.size.width ? contentOffsetForCell(withFrame: toFrame, andIndex: toIndex) : 0 setContentOffset(CGPoint(x: targetContentOffset, y: 0), animated: animated) } private func contentOffsetForCell(withFrame cellFrame: CGRect, andIndex index: Int) -> CGFloat { let alignmentOffset = (frame.size.width - cellFrame.size.width) * 0.5 var contentOffset = cellFrame.origin.x - alignmentOffset contentOffset = max(0, contentOffset) contentOffset = min(contentSize.width - frame.size.width, contentOffset) return contentOffset } private func updateSelectedBarYPosition() { var selectedBarFrame = selectedBar.frame selectedBarFrame.origin.y = frame.size.height - selectedBarHeight selectedBarFrame.size.height = selectedBarHeight selectedBar.frame = selectedBarFrame } override open func layoutSubviews() { super.layoutSubviews() updateSelectedBarYPosition() } }