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Add Keyboard Shortcuts to SwiftUI on iOS 13 when using `UIHostingController`. Requires using KeyboardEnabledHostingController as hosting class) See https://steipete.com/posts/fixing-keyboardshortcut-in-swiftui/
//
// KeyCommand.swift
// Adds Keyboard Shortcuts to SwiftUI on iOS 13
// See https://steipete.com/posts/fixing-keyboardshortcut-in-swiftui/
// License: MIT
//
// Usage: (wrap view in `KeyboardEnabledHostingController`)
// Button(action: {
// print("Button Tapped!!")
// }) {
// Text("Button")
// }
// .keyCommand("e", modifiers: [.control])
import SwiftUI
import Combine
/// Subclass for `UIHostingController` that enables using the `onKeyCommand` extension.
@available(iOS 13.0, *)
class KeyboardEnabledHostingController<Content>: UIHostingController<KeyboardEnabledHostingController.Wrapper> where Content: View {
private let registrator = KeyCommandRegistrator()
init(rootView: Content) {
super.init(rootView: Wrapper(content: rootView, registrator: registrator))
}
struct Wrapper: View {
let content: Content
fileprivate let registrator: KeyCommandRegistrator
var body: some View {
content.environmentObject(registrator)
}
}
@objc required dynamic init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override var keyCommands: [UIKeyCommand]? {
registrator.keyCommands + (super.keyCommands ?? [])
}
// This method must be inside a responder, else it's hidden
@objc private func performKeyCommand(_ keyCommand: UIKeyCommand) {
guard let input = keyCommand.input else { return }
let keyPair = KeyCommandPair(input: input, modifiers: keyCommand.modifierFlags)
registrator.keyPublisher.send(keyPair)
}
override var canBecomeFirstResponder: Bool { true }
}
@available(iOS 13.0, *)
private struct KeyCommandStyle: PrimitiveButtonStyle {
var commandPair: KeyCommandPair
// Purely additive style: https://developer.apple.com/documentation/swiftui/button/init(_:)
func makeBody(configuration: Configuration) -> some View {
Button(configuration)
.keyCommand(keyPair: commandPair, action: configuration.trigger)
}
}
@available(iOS 13.0, *)
extension View {
/// Register a key command for the current button, invoking the button action when triggered.
func keyCommand(_ key: String, modifiers: UIKeyModifierFlags = .command, title: String = "") -> some View {
buttonStyle(KeyCommandStyle(commandPair: KeyCommandPair(input: key, modifiers: modifiers)))
}
/// Register a key command for the current view
func onKeyCommand(_ key: String, modifiers: UIKeyModifierFlags = .command, title: String = "", action: @escaping () -> Void) -> some View {
keyCommand(keyPair: KeyCommandPair(input: key, modifiers: modifiers, title: title), action: action)
}
fileprivate func keyCommand(keyPair: KeyCommandPair, action: @escaping () -> Void) -> some View {
self.modifier(KeyCommandModifier(commandPair: keyPair, action: action))
}
}
@available(iOS 13.0, *)
private struct KeyCommandModifier: ViewModifier {
@EnvironmentObject var registrator: KeyCommandRegistrator
fileprivate var commandPair: KeyCommandPair
var action: () -> Void
func body(content: Content) -> some View {
content
.padding(0) // without a modification, onReceive is not called
.onReceive(registrator.keyPublisher.filter { $0 == self.commandPair }) { _ in action() }
.onAppear {
registrator.register(commandPair)
}
}
}
@available(iOS 13.0, *)
private class KeyCommandRegistrator: ObservableObject {
var keyCommands: [UIKeyCommand] = []
let keyPublisher = PassthroughSubject<KeyCommandPair, Never>()
func register(_ commandPair: KeyCommandPair) {
let command = UIKeyCommand(title: commandPair.title ?? "",
action: NSSelectorFromString("performKeyCommand:"),
input: commandPair.input,
modifierFlags: commandPair.modifiers)
keyCommands += [command]
}
}
@available(iOS 13.0, *)
private struct KeyCommandPair: Equatable {
var input: String
var modifiers: UIKeyModifierFlags
var title: String?
static func == (lhs: KeyCommandPair, rhs: KeyCommandPair) -> Bool {
return lhs.input == rhs.input && lhs.modifiers == rhs.modifiers
}
}
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