95 lines
3.3 KiB
Swift
95 lines
3.3 KiB
Swift
//
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// Copyright (c) 2015 Max Sokolov https://twitter.com/max_sokolov
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy of
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// this software and associated documentation files (the "Software"), to deal in
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// the Software without restriction, including without limitation the rights to
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// use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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// the Software, and to permit persons to whom the Software is furnished to do so,
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// subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in all
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// copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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// FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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// COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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// IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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// CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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import UIKit
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public protocol CellHeightCalculatable {
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func height(_ row: Row, path: IndexPath) -> CGFloat
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func estimatedHeight(_ row: Row, path: IndexPath) -> CGFloat
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func invalidate()
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}
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open class PrototypeHeightStrategy: CellHeightCalculatable {
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private weak var tableView: UITableView?
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private var prototypes = [String: UITableViewCell]()
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private var cachedHeights = [Int: CGFloat]()
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private var separatorHeight = 1 / UIScreen.main.scale
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init(tableView: UITableView?) {
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self.tableView = tableView
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}
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open func height(_ row: Row, path: IndexPath) -> CGFloat {
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guard let tableView = tableView else { return 0 }
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let hash = row.hashValue ^ Int(tableView.bounds.size.width).hashValue
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if let height = cachedHeights[hash] {
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return height
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}
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var prototypeCell = prototypes[row.reuseIdentifier]
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if prototypeCell == nil {
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prototypeCell = tableView.dequeueReusableCell(withIdentifier: row.reuseIdentifier)
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prototypes[row.reuseIdentifier] = prototypeCell
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}
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guard let cell = prototypeCell else { return 0 }
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row.configure(cell)
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cell.bounds = CGRect(x: 0, y: 0, width: tableView.bounds.size.width, height: cell.bounds.height)
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cell.setNeedsLayout()
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cell.layoutIfNeeded()
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let height = cell.contentView.systemLayoutSizeFitting(UILayoutFittingCompressedSize).height + (tableView.separatorStyle != .none ? separatorHeight : 0)
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cachedHeights[hash] = height
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return height
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}
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open func estimatedHeight(_ row: Row, path: IndexPath) -> CGFloat {
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guard let tableView = tableView else { return 0 }
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let hash = row.hashValue ^ Int(tableView.bounds.size.width).hashValue
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if let height = cachedHeights[hash] {
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return height
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}
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if let estimatedHeight = row.estimatedHeight , estimatedHeight > 0 {
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return estimatedHeight
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}
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return UITableViewAutomaticDimension
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}
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open func invalidate() {
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cachedHeights.removeAll()
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}
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}
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