50 lines
2.0 KiB
Swift
50 lines
2.0 KiB
Swift
//
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// LoadMoreConfigurableTableViewContainer.swift
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// Mastodon
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//
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// Created by sxiaojian on 2021/2/3.
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//
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import UIKit
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import GameplayKit
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/// The tableView container driven by state machines with "LoadMore" logic
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protocol LoadMoreConfigurableTableViewContainer: UIViewController {
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associatedtype BottomLoaderTableViewCell: UITableViewCell
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associatedtype LoadingState: GKState
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var loadMoreConfigurableTableView: UITableView { get }
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var loadMoreConfigurableStateMachine: GKStateMachine { get }
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func handleScrollViewDidScroll(_ scrollView: UIScrollView)
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}
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extension LoadMoreConfigurableTableViewContainer {
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func handleScrollViewDidScroll(_ scrollView: UIScrollView) {
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guard scrollView === loadMoreConfigurableTableView else { return }
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// check if current scroll position is the bottom of table
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let contentOffsetY = loadMoreConfigurableTableView.contentOffset.y
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let bottomVisiblePageContentOffsetY = loadMoreConfigurableTableView.contentSize.height - (1.5 * loadMoreConfigurableTableView.visibleSize.height)
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guard contentOffsetY > bottomVisiblePageContentOffsetY else {
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return
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}
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let cells = loadMoreConfigurableTableView.visibleCells.compactMap { $0 as? BottomLoaderTableViewCell }
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guard let loaderTableViewCell = cells.first else { return }
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if let tabBar = tabBarController?.tabBar, let window = view.window {
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let loaderTableViewCellFrameInWindow = loadMoreConfigurableTableView.convert(loaderTableViewCell.frame, to: nil)
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let windowHeight = window.frame.height
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let loaderAppear = (loaderTableViewCellFrameInWindow.origin.y + 0.8 * loaderTableViewCell.frame.height) < (windowHeight - tabBar.frame.height)
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if loaderAppear {
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loadMoreConfigurableStateMachine.enter(LoadingState.self)
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} else {
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// do nothing
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}
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} else {
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loadMoreConfigurableStateMachine.enter(LoadingState.self)
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}
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}
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}
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