65 lines
2.5 KiB
Swift
65 lines
2.5 KiB
Swift
import UIKit
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class SearchBarManager: NSObject, UISearchResultsUpdating {
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private(set) var isActive = false
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private(set) var term = ""
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private lazy var controller: UISearchController = {
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let x = UISearchController(searchResultsController: nil)
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x.searchBar.autocapitalizationType = .none
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x.searchBar.autocorrectionType = .no
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x.obscuresBackgroundDuringPresentation = false
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x.searchResultsUpdater = self
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return x
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}()
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private weak var tvc: UITableViewController?
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private let onChangeCallback: (String) -> Void
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/// Prepare `UISearchBar` for user input
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/// - Parameter onChange: Code that will be executed every time the user changes the text (with 0.2s delay)
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required init(onChange: @escaping (String) -> Void) {
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onChangeCallback = onChange
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super.init()
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UITextField.appearance(whenContainedInInstancesOf: [UISearchBar.self])
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.defaultTextAttributes = [.font: UIFont.preferredFont(forTextStyle: .body)]
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}
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/// Assigns the `UISearchBar` to `tableView.tableHeaderView` (iOS 9) or `navigationItem.searchController` (iOS 11).
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func fuseWith(tableViewController: UITableViewController?) {
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guard tvc !== tableViewController else { return }
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tvc = tableViewController
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if #available(iOS 11.0, *) {
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tvc?.navigationItem.searchController = controller
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} else {
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let thv = tvc?.tableView.tableHeaderView
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guard thv == nil || thv is UISearchBar else {
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// Don't overwrite actions bar (co-occurrence, etc.)
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// FIXME: find alternative or iOS 9-10 users can't search in hosts
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tvc = nil
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return
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}
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controller.loadViewIfNeeded() // Fix: "Attempting to load the view of a view controller while it is deallocating"
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tvc?.definesPresentationContext = true // make search bar disappear if user changes scene (eg. select cell)
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//tvc?.tableView.backgroundView = UIView() // iOS 11+ bug: bright white background in dark mode
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tvc?.tableView.tableHeaderView = controller.searchBar
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tvc?.tableView.setContentOffset(.init(x: 0, y: controller.searchBar.frame.height), animated: false)
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}
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}
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/// Search callback
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internal func updateSearchResults(for controller: UISearchController) {
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NSObject.cancelPreviousPerformRequests(withTarget: self, selector: #selector(performSearch), object: nil)
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perform(#selector(performSearch), with: nil, afterDelay: 0.2)
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}
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/// Internal callback function for delayed text evaluation.
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/// This way we can avoid unnecessary searches while user is typing.
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@objc private func performSearch() {
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term = controller.searchBar.text?.lowercased() ?? ""
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isActive = term.count > 0
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onChangeCallback(term)
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}
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}
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