111 lines
3.4 KiB
Swift
111 lines
3.4 KiB
Swift
import UIKit
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/// Assigns a `UISearchBar` to the `tableHeaderView` property of a `UITableView`.
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class SearchBarManager: NSObject, UISearchBarDelegate {
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private weak var tableView: UITableView?
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private let searchBar: UISearchBar
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private(set) var active: Bool = false
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typealias OnChange = (String) -> Void
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typealias OnHide = () -> Void
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private var onChangeCallback: OnChange!
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private var onHideCallback: OnHide?
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/// Prepare `UISearchBar` for user input
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/// - Parameter tableView: The `tableHeaderView` property is used for display.
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required init(on tableView: UITableView) {
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self.tableView = tableView
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searchBar = UISearchBar(frame: CGRect.init(x: 0, y: 0, width: 20, height: 10))
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searchBar.sizeToFit() // sets height, width is set by table view header
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searchBar.showsCancelButton = true
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searchBar.autocapitalizationType = .none
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searchBar.autocorrectionType = .no
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super.init()
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searchBar.delegate = self
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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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// MARK: Show & Hide
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/// Insert search bar in `tableView` and call `reloadData()` after animation.
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/// - Parameters:
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/// - onHide: Code that will be executed once the search bar is dismissed.
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/// - onChange: Code that will be executed every time the user changes the text (with 0.2s delay)
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func show(onHide: OnHide? = nil, onChange: @escaping OnChange) {
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onChangeCallback = onChange
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onHideCallback = onHide
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setSearchBarHidden(false)
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}
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/// Remove search bar from `tableView` and call `reloadData()` after animation.
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func hide() {
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setSearchBarHidden(true)
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}
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/// Internal method to insert or remove the `UISearchBar` as `tableHeaderView`
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private func setSearchBarHidden(_ flag: Bool) {
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active = !flag
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searchBar.text = nil
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guard let tv = tableView else {
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hideAndRelease()
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return
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}
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if active {
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tv.scrollToTop(animated: false)
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tv.tableHeaderView = searchBar
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tv.frame.origin.y = -searchBar.frame.height
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UIView.animate(withDuration: 0.3, animations: {
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tv.frame.origin.y = 0
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}) { _ in
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tv.reloadData()
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self.searchBar.becomeFirstResponder()
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}
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} else {
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searchBar.resignFirstResponder()
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UIView.animate(withDuration: 0.3, animations: {
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tv.frame.origin.y = -(tv.tableHeaderView?.frame.height ?? 0)
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tv.scrollToTop(animated: false) // false to let UIView animate the change
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}) { _ in
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tv.frame.origin.y = 0
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self.hideAndRelease()
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tv.reloadData()
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}
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}
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}
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/// Call `OnHide` closure (if set), then release strong closure references.
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private func hideAndRelease() {
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tableView?.tableHeaderView = nil
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onHideCallback?()
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onHideCallback = nil
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onChangeCallback = nil
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}
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// MARK: Search Bar Delegate
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func searchBarCancelButtonClicked(_ _: UISearchBar) {
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setSearchBarHidden(true)
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}
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func searchBarSearchButtonClicked(_ searchBar: UISearchBar) {
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searchBar.resignFirstResponder()
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}
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func searchBar(_ _: UISearchBar, textDidChange _: String) {
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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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onChangeCallback(searchBar.text ?? "")
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tableView?.reloadData()
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}
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}
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