david-swift
1c50b3b923
Make one @State always reference the same value This is important when views with closures appear after the first render
122 lines
4.3 KiB
Swift
122 lines
4.3 KiB
Swift
//
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// List.swift
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// Adwaita
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//
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// Created by david-swift on 25.09.23.
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//
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import LevenshteinTransformations
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import Libadwaita
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/// A list box widget.
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public struct List<Element>: Widget where Element: Identifiable {
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/// The elements.
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var elements: [Element]
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/// The content.
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var content: (Element) -> Body
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/// The identifier of the selected element.
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@Binding var selection: Element.ID
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/// The identifier of the elements storage.
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let elementsID = "elements"
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/// Initialize `List`.
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/// - Parameters:
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/// - elements: The elements.
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/// - selection: The identifier of the selected element.
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/// - content: The view for an element.
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public init(
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_ elements: [Element],
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selection: Binding<Element.ID>,
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@ViewBuilder content: @escaping (Element) -> Body
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) {
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self.content = content
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self.elements = elements
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self._selection = selection
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}
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/// Update a view storage.
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/// - Parameters:
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/// - storage: The view storage.
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/// - modifiers: Modify views before being updated.
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public func update(_ storage: ViewStorage, modifiers: [(View) -> View]) {
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if let box = storage.view as? ListBox {
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var content: [ViewStorage] = storage.content[.mainContent] ?? []
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updateList(box: box, content: .init { content } set: { content = $0 }, modifiers: modifiers)
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storage.content[.mainContent] = content
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for (index, element) in elements.enumerated() {
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self.content(element).widget(modifiers: modifiers).update(content[index], modifiers: modifiers)
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}
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}
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}
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/// Get a view storage.
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/// - Parameter modifiers: Modify views before being updated.
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/// - Returns: The view storage.
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public func container(modifiers: [(View) -> View]) -> ViewStorage {
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let box: ListBox = .init()
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var content: [ViewStorage] = []
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updateList(box: box, content: .init { content } set: { content = $0 }, modifiers: modifiers)
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_ = box.handler {
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let selection = box.getSelectedRow()
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if let id = (box.fields[elementsID] as? [Element] ?? elements)[safe: selection]?.id {
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self.selection = id
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}
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}
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return .init(box, content: [.mainContent: content])
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}
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/// Update the list's content and selection.
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/// - Parameters:
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/// - box: The list box.
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/// - content: The content's view storage.
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/// - modifiers: The view modifiers.
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func updateList(box: ListBox, content: Binding<[ViewStorage]>, modifiers: [(View) -> View]) {
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let old = box.fields[elementsID] as? [Element] ?? []
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old.identifiableTransform(
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to: elements,
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functions: .init { index, element in
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let widget = getWidget(element: element, modifiers: modifiers)
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_ = box.remove(at: index)
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_ = box.insert(widget.view, at: index)
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content.wrappedValue.remove(at: index)
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content.wrappedValue.insert(widget, at: index)
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} delete: { index in
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_ = box.remove(at: index)
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content.wrappedValue.remove(at: index)
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updateSelection(box: box)
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} insert: { index, element in
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let widget = getWidget(element: element, modifiers: modifiers)
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_ = box.insert(widget.view, at: index)
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content.wrappedValue.insert(widget, at: index)
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}
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)
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box.fields[elementsID] = elements
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updateSelection(box: box)
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}
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/// Update the list's selection.
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/// - Parameter box: The list box.
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func updateSelection(box: ListBox) {
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if let index = elements.firstIndex(where: { $0.id == selection }) {
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box.selectRow(at: index)
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}
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}
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/// Get the view storage of an element.
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/// - Parameters:
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/// - element: The element.
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/// - modifiers: The modifiers.
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/// - Returns: The view storage.
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func getWidget(element: Element, modifiers: [(View) -> View]) -> ViewStorage {
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self.content(element).widget(modifiers: modifiers).container(modifiers: modifiers)
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}
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/// Add the "navigation-sidebar" style class.
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public func sidebarStyle() -> View {
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style("navigation-sidebar")
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}
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}
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