Add Defaults.Toggle (#69)

Sources/Defaults/SwiftUI.swift

@@ -5,10 +5,11 @@ import Combine
 @available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
 extension Defaults {
  final class Observable<Value: Serializable>: ObservableObject {
- let objectWillChange = ObservableObjectPublisher()
  private var observation: DefaultsObservation?
  private let key: Defaults.Key<Value>
 
+ let objectWillChange = ObservableObjectPublisher()
+
  var value: Value {
  get { Defaults[key] }
  set {
@@ -44,6 +45,8 @@ public struct Default<Value: Defaults.Serializable>: DynamicProperty {
  public typealias Publisher = AnyPublisher<Defaults.KeyChange<Value>, Never>
 
  private let key: Defaults.Key<Value>
+
+ // Intentionally using `@ObservedObjected` over `@StateObject` so that the key can be dynamicaly changed.
  @ObservedObject private var observable: Defaults.Observable<Value>
 
  /**
@@ -61,7 +64,10 @@ public struct Default<Value: Defaults.Serializable>: DynamicProperty {
 
  var body: some View {
  Text("Has Unicorn: \(hasUnicorn)")
- Toggle("Toggle Unicorn", isOn: $hasUnicorn)
+ Toggle("Toggle", isOn: $hasUnicorn)
+ Button("Reset") {
+ _hasUnicorn.reset()
+ }
  }
  }
  ```
@@ -110,4 +116,101 @@ public struct Default<Value: Defaults.Serializable>: DynamicProperty {
  key.reset()
  }
 }
+
+@available(macOS 11, iOS 14, tvOS 14, watchOS 7, *)
+extension Defaults {
+ /**
+ Creates a SwiftUI `Toggle` view that is connected to a `Defaults` key with a `Bool` value.
+
+ The toggle works exactly like the SwiftUI `Toggle`.
+
+ ```
+ extension Defaults.Keys {
+ static let showAllDayEvents = Key<Bool>("showAllDayEvents", default: false)
+ }
+
+ struct ShowAllDayEventsSetting: View {
+ var body: some View {
+ Defaults.Toggle("Show All-Day Events", key: .showAllDayEvents)
+ }
+ }
+ ```
+
+ You can also listen to changes:
+
+ ```
+ struct ShowAllDayEventsSetting: View {
+ var body: some View {
+ Defaults.Toggle("Show All-Day Events", key: .showAllDayEvents)
+ // Note that this has to be directly attached to `Defaults.Toggle`. It's not `View#onChange()`.
+ .onChange {
+ print("Value", $0)
+ }
+ }
+ }
+ ```
+ */
+ public struct Toggle<Label, Key>: View where Label: View, Key: Defaults.Key<Bool> {
+ @ViewStorage private var onChange: ((Bool) -> Void)?
+
+ private let label: () -> Label
+
+ // Intentionally using `@ObservedObjected` over `@StateObject` so that the key can be dynamicaly changed.
+ @ObservedObject private var observable: Defaults.Observable<Bool>
+
+ public init(key: Key, @ViewBuilder label: @escaping () -> Label) {
+ self.label = label
+ self.observable = Defaults.Observable(key)
+ }
+
+ public var body: some View {
+ SwiftUI.Toggle(isOn: $observable.value, label: label)
+ .onChange(of: observable.value) {
+ onChange?($0)
+ }
+ }
+ }
+}
+
+@available(macOS 11, iOS 14, tvOS 14, watchOS 7, *)
+extension Defaults.Toggle where Label == Text {
+ public init<S>(_ title: S, key: Defaults.Key<Bool>) where S: StringProtocol {
+ self.label = { Text(title) }
+ self.observable = Defaults.Observable(key)
+ }
+}
+
+@available(macOS 11, iOS 14, tvOS 14, watchOS 7, *)
+extension Defaults.Toggle {
+ /// Do something when the value changes to a different value.
+ public func onChange(_ action: @escaping (Bool) -> Void) -> Self {
+ onChange = action
+ return self
+ }
+}
+
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, watchOS 6.0, *)
+@propertyWrapper
+private struct ViewStorage<Value>: DynamicProperty {
+ private final class ValueBox {
+ var value: Value
+
+ init(_ value: Value) {
+ self.value = value
+ }
+ }
+
+ @State private var valueBox: ValueBox
+
+ var wrappedValue: Value {
+ get { valueBox.value }
+ nonmutating set {
+ valueBox.value = newValue
+ }
+ }
+
+ init(wrappedValue value: @autoclosure @escaping () -> Value) {
+ self._valueBox = .init(wrappedValue: ValueBox(value()))
+ }
+}
 #endif

readme.md

@@ -153,6 +153,8 @@ Defaults[isUnicorn]
 
 ### SwiftUI support
 
+#### `@Default`
+
 You can use the `@Default` property wrapper to get/set a `Defaults` item and also have the view be updated when the value changes. This is similar to `@State`.
 
 ```swift
@@ -165,7 +167,10 @@ struct ContentView: View {
 
  var body: some View {
  Text("Has Unicorn: \(hasUnicorn)")
- Toggle("Toggle Unicorn", isOn: $hasUnicorn)
+ Toggle("Toggle", isOn: $hasUnicorn)
+ Button("Reset") {
+ _hasUnicorn.reset()
+ }
  }
 }
 ```
@@ -174,6 +179,38 @@ Note that it's `@Default`, not `@Defaults`.
 
 You cannot use `@Default` in an `ObservableObject`. It's meant to be used in a `View`.
 
+#### `Toggle`
+
+There's also a `SwiftUI.Toggle` wrapper that makes it easier to create a toggle based on a `Defaults` key with a `Bool` value.
+
+```swift
+extension Defaults.Keys {
+ static let showAllDayEvents = Key<Bool>("showAllDayEvents", default: false)
+}
+
+struct ShowAllDayEventsSetting: View {
+ var body: some View {
+ Defaults.Toggle("Show All-Day Events", key: .showAllDayEvents)
+ }
+}
+```
+
+You can also listen to changes:
+
+```swift
+struct ShowAllDayEventsSetting: View {
+ var body: some View {
+ Defaults.Toggle("Show All-Day Events", key: .showAllDayEvents)
+ // Note that this has to be directly attached to `Defaults.Toggle`. It's not `View#onChange()`.
+ .onChange {
+ print("Value", $0)
+ }
+ }
+}
+```
+
+*Requires at least macOS 11, iOS 14, tvOS 14, watchOS 7.*
+
 ### Observe changes to a key
 
 ```swift