App

@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
public protocol App {

    /// The type of scene representing the content of the app.
    ///
    /// When you create a custom app, Swift infers this type from your
    /// implementation of the required ``SwiftUI/App/body-swift.property``
    /// property.
    associatedtype Body : Scene

    /// The content and behavior of the app.
    ///
    /// For any app that you create, provide a computed `body` property that
    /// defines your app's scenes, which are instances that conform to the
    /// ``SwiftUI/Scene`` protocol. For example, you can create a simple app
    /// with a single scene containing a single view:
   // 对于你创建的任何应用程序，提供一个计算过的' body '属性
  ///  定义应用程序的场景，这些场景是符合的实例
  /// 'SwiftUI/Scene'协议。例如，您可以创建一个简单的应用程序
  /// 单个场景包含单个视图:
    ///
    ///     @main
    ///     struct MyApp: App {
    ///         var body: some Scene {
    ///             WindowGroup {
    ///                 Text("Hello, world!")
    ///             }
    ///         }
    ///     }
    ///
    /// Swift infers the app's ``SwiftUI/App/Body-swift.associatedtype``
    /// associated type based on the scene provided by the `body` property.
    @SceneBuilder var body: Self.Body { get }

    /// Creates an instance of the app using the body that you define for its
    /// content.
    ///
    /// Swift synthesizes a default initializer for structures that don't
    /// provide one. You typically rely on the default initializer for
    /// your app.
    init()
}

@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
extension App {

    /// Initializes and runs the app.
    ///
    /// If you precede your ``SwiftUI/App`` conformer's declaration with the
    /// [@main](https://docs.swift.org/swift-book/ReferenceManual/Attributes.html#ID626)
    /// attribute, the system calls the conformer's `main()` method to launch
    /// the app. SwiftUI provides a
    /// default implementation of the method that manages the launch process in
    /// a platform-appropriate way.
// 初始化并运行应用程序。
///
/// 如果您在“SwiftUI/App”conformer的声明前加上
/// [@main] (https://docs.swift.org/swift-book/ReferenceManual/Attributes.html # ID626)
/// 属性时，系统调用conformer的' main() '方法启动
/// SwiftUI提供了一个
/// 中管理启动进程的方法的默认实现
/// 适合平台的方式。
    public static func main()
}

WindwoGroup

/// A scene that presents a group of identically structured windows.
///
/// Use a `WindowGroup` as a container for a view hierarchy presented by your
/// app. The hierarchy that you declare as the group's content serves as a
/// template for each window that the app creates from that group:
// 呈现一组结构相同的窗口的场景。
///
/// 使用' WindowGroup '作为视图层次结构的容器
/// 您声明为组内容的层次结构充当
/// 应用程序从该组创建的每个窗口模板:
///
///     @main
///     struct Mail: App {
///         var body: some Scene {
///             WindowGroup {
///                 MailViewer() // Declare a view hierarchy here.
///             }
///         }
///     }
@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
public struct WindowGroup<Content> : Scene where Content : View {}

Scene

@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
public protocol Scene {

    /// The type of scene that represents the body of this scene.
    ///
    /// When you create a custom scene, Swift infers this type from your
    /// implementation of the required ``SwiftUI/Scene/body-swift.property``
    /// property.
    associatedtype Body : Scene

    /// The content and behavior of the scene.
    ///
    /// For any scene that you create, provide a computed `body` property that
    /// defines the scene as a composition of other scenes. You can assemble a
    /// scene from primitive scenes that SwiftUI provides, as well as other
    /// scenes that you've defined.
    ///
    /// Swift infers the scene's ``SwiftUI/Scene/Body-swift.associatedtype``
    /// associated type based on the contents of the `body` property.
   /// 场景的内容和行为。
  ///
 /// 对于你创建的任何场景，提供一个计算过的' body '属性
 /// 将场景定义为其他场景的组成。你可以组装一个
 /// 来自SwiftUI提供的原始场景的场景，以及其他
 /// 您定义的场景。
 ///
 /// Swift推断场景的' ' SwiftUI/ scene / body - speed .associatedtype ' '
 /// 基于“body”属性内容的关联类型。
    @SceneBuilder var body: Self.Body { get }
}

@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
extension Scene {

    /// Adds an action to perform when the given value changes.
    ///
    /// Use this modifier to trigger a side effect when a value changes, like
    /// the value associated with an ``SwiftUI/Environment`` key or a
    /// ``SwiftUI/Binding``. For example, you can clear a cache when you notice
    /// that a scene moves to the background:
   /// 添加给定值更改时执行的操作。
   ///
  /// 当值更改时，使用此修饰符触发副作用，例如
  /// 与' ' SwiftUI/Environment ' '键关联的值
  /// ‘SwiftUI /绑定”。例如，您可以在注意到时清除缓存
   ///场景移到背景:
    ///
    ///     struct MyScene: Scene {
    ///         @Environment(\.scenePhase) private var scenePhase
    ///         @StateObject private var cache = DataCache()
    ///
    ///         var body: some Scene {
    ///             WindowGroup {
    ///                 MyRootView()
    ///             }
    ///             .onChange(of: scenePhase) { newScenePhase in
    ///                 if newScenePhase == .background {
    ///                     cache.empty()
    ///                 }
    ///             }
    ///         }
    ///     }
    ///
    /// The system calls the `action` closure on the main thread, so avoid
    /// long-running tasks in the closure. If you need to perform such tasks,
    /// dispatch to a background queue:
    ///
    ///     .onChange(of: scenePhase) { newScenePhase in
    ///         if newScenePhase == .background {
    ///             DispatchQueue.global(qos: .background).async {
    ///                 // ...
    ///             }
    ///         }
    ///     }
    ///
    /// The system passes the new value into the closure. If you need the old
    /// value, capture it in the closure.
    ///
    /// - Parameters:
    ///   - value: The value to check when determining whether to run the
    ///     closure. The value must conform to the
    ///     <doc://com.apple.documentation/documentation/Swift/Equatable>
    ///     protocol.
    ///   - action: A closure to run when the value changes. The closure
    ///     provides a single `newValue` parameter that indicates the changed
    ///     value.
    ///
    /// - Returns: A scene that triggers an action in response to a change.
// 系统将新值传递到闭包。如果你需要老人值，在闭包中捕获它。
///
///  -参数:
/// - value:决定是否运行时要检查的值
/// 关闭。值必须符合
///<doc://com.apple.documentation/documentation/Swift/Equatable>
///协议。
///  - action:当值更改时运行的闭包。关闭
/// 提供一个单独的“newValue”参数来指示更改的值
///值。
///
/// -返回:一个场景，触发一个动作来响应一个变化。
    @inlinable public func onChange<V>(of value: V, perform action: @escaping (V) -> Void) -> some Scene where V : Equatable

}

@available(iOS 14.0, macOS 11.0, *)
@available(tvOS, unavailable)
@available(watchOS, unavailable)
extension Scene {

    /// Adds commands to the scene.
    ///
    /// Commands are realized in different ways on different platforms. On
    /// macOS, the main menu uses the available command menus and groups to
    /// organize its main menu items. Each menu is represented as a top-level
    /// menu bar menu, and each command group has a corresponding set of menu
    /// items in one of the top-level menus, delimited by separator menu items.
    ///
    /// On iPadOS, commands with keyboard shortcuts are exposed in the shortcut
    /// discoverability HUD that users see when they hold down the Command (⌘)
    /// key.
/// 向场景添加命令。
/// 命令在不同的平台上以不同的方式实现。在
// macOS中，主菜单使用可用的命令菜单和组来实现
/// 组织其主要菜单项。每个菜单都表示为顶级菜单
/// 菜单栏菜单，并且每个命令组都有对应的一组菜单
/// 顶级菜单中的项，由分隔符菜单项分隔。
/// 
/// 在iPadOS上，带有键盘快捷键的命令会在快捷键中显示
/// 可发现性住房和城市发展部,用户看到时按住命令(⌘)
/// 关键。

    public func commands<Content>(@CommandsBuilder content: () -> Content) -> some Scene where Content : Commands

}

@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
extension Scene {

    /// The default store used by `AppStorage` contained within the scene and
    /// its view content.
    ///
    /// If unspecified, the default store for a view hierarchy is
    /// `UserDefaults.standard`, but can be set a to a custom one. For example,
    /// sharing defaults between an app and an extension can override the
    /// default store to one created with `UserDefaults.init(suiteName:_)`.
    ///
    /// - Parameter store: The user defaults to use as the default
    ///   store for `AppStorage`.
/// 场景中包含的“AppStorage”使用的默认存储
/// 其视图内容。
///
/// 如果未指定，视图层次结构的默认存储为
/// UserDefaults。标准，但可以设置为自定义。例如,
/// 在应用程序和扩展之间共享默认值可以覆盖
/// 默认存储为用' UserDefaults.init(suiteName:_) '创建的。
///
/// -参数存储:用户默认使用为默认值
/// store for ' AppStorage '。
    public func defaultAppStorage(_ store: UserDefaults) -> some Scene

}

@available(iOS 14.0, macOS 11.0, *)
@available(tvOS, unavailable)
@available(watchOS, unavailable)
extension Scene {

    /// Specifies a modifier to indicate if this Scene can be used
    /// when creating a new Scene for the received External Event.
    ///
    /// This modifier is only supported for WindowGroup Scene types.
    ///
    /// For DocumentGroups, the received External Event must have a URL
    /// for the DocumentGroup to be considered. (Either via openURL, or
    /// the webPageURL property of an NSUserActivity). The UTI for the URL
    /// is implicitly matched against the DocumentGroup's supported types.
    ///
    /// If the modifier evaluates to true, an instance of the
    /// Scene will be used.
    ///
    /// If the modifier evaluates to false, on macOS the Scene
    /// will not be used even if no other Scenes are available.
    /// This case is considered an error. On iOS, the first Scene
    /// specified in the body property for the App will be used.
    ///
    /// If no modifier is set, the Scene will be used if all
    /// other WindowGroups with a modifier evaluate to false.
    ///
    /// On platforms that only allow a single Window/Scene, this method is
    /// ignored.
    ///
    /// - Parameter matching: A Set of Strings that are checked to see
    /// if they are contained in the targetContentIdenfifier. The empty Set
    /// and empty Strings never match. The String value "*" always matches.
/// 指定一个修饰符来指示这个场景是否可以使用
/// 当为接收到的外部事件创建一个新场景时。
///
/// 这个修改器只支持WindowGroup场景类型。
///
/// 对于DocumentGroups，接收的外部事件必须有一个URL
/// 要考虑的DocumentGroup。(要么通过openURL，要么
/// NSUserActivity的webPageURL属性)。URL的UTI
/// 与DocumentGroup支持的类型隐式匹配。
///
/// 如果修饰符的值为真，则
/// 场景将被使用。
///
/// 如果修改器的值为false，在macOS场景中
/// 将不会被使用，即使没有其他场景可用。
/// 这种情况被认为是一个错误。在iOS上，第一个场景
/// 在body属性中指定的应用程序将被使用。
///
/// 如果没有设置修改器，场景将被使用
/// 修改符为false的其他窗口组。
///
/// 在只允许单个窗口/场景的平台上，此方法为
/// 忽略。
///
///  -参数匹配:要检查的一组字符串
/// 如果它们包含在targetContentIdenfifier中。空集
/// 和空字符串永远不匹配。字符串值“*”总是匹配的。

  public func handlesExternalEvents(matching conditions: Set<String>) -> some Scene
}

SceneBuilder

/// A function builder for composing a collection of scenes into a single
/// composite scene.
/// 一个函数构建器，用于将一组场景组合成单个场景
/// 复合场景。
@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
@_functionBuilder public struct SceneBuilder {

    /// Passes a single scene written as a child scene through unmodified.
    public static func buildBlock<Content>(_ content: Content) -> Content where Content : Scene
}

@_functionBuilder

@ViewBuilder

// A custom parameter attribute that constructs views from closures.
///
/// You typically use ``ViewBuilder`` as a parameter attribute for child
/// view-producing closure parameters, allowing those closures to provide
/// multiple child views. For example, the following `contextMenu` function
/// accepts a closure that produces one or more views via the view builder.
/// 从闭包构造视图的自定义参数属性。
///
/// 你通常使用' ' ViewBuilder ' '作为child的参数属性
/// 视图生成闭包参数，允许这些闭包提供
/// 多个子视图。例如，下面的“contextMenu”函数
/// 接受一个闭包，该闭包通过视图生成器生成一个或多个视图。
///
///     func contextMenu<MenuItems : View>(
///         @ViewBuilder menuItems: () -> MenuItems
///     ) -> some View
///
/// Clients of this function can use multiple-statement closures to provide
/// several child views, as shown in the following example:
///
/// 该函数的客户端可以使用多语句闭包来提供
/// 几个子视图，如下面的例子所示:
///     myView.contextMenu {
///         Text("Cut")
///         Text("Copy")
///         Text("Paste")
///         if isSymbol {
///             Text("Jump to Definition")
///         }
///     }
///

@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
@_functionBuilder public struct ViewBuilder {

    /// Builds an empty view from a block containing no statements.
    public static func buildBlock() -> EmptyView

    /// Passes a single view written as a child view through unmodified.
    ///
    /// An example of a single view written as a child view is
    /// `{ Text("Hello") }`.
    public static func buildBlock<Content>(_ content: Content) -> Content where Content : View
}

@available(iOS 13.0, macOS 10.15, tvOS 13.0, watchOS 6.0, *)
extension ViewBuilder {

    /// Provides support for “if” statements in multi-statement closures,
    /// producing an optional view that is visible only when the condition
    /// evaluates to `true`.
    public static func buildIf<Content>(_ content: Content?) -> Content? where Content : View

    /// Provides support for "if" statements in multi-statement closures,
    /// producing conditional content for the "then" branch.
    public static func buildEither<TrueContent, FalseContent>(first: TrueContent) -> _ConditionalContent<TrueContent, FalseContent> where TrueContent : View, FalseContent : View

    /// Provides support for "if-else" statements in multi-statement closures,
    /// producing conditional content for the "else" branch.
    public static func buildEither<TrueContent, FalseContent>(second: FalseContent) -> _ConditionalContent<TrueContent, FalseContent> where TrueContent : View, FalseContent : View
}

@available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
extension ViewBuilder {

    /// Provides support for "if" statements with `#available()` clauses in
    /// multi-statement closures, producing conditional content for the "then"
    /// branch, i.e. the conditionally-available branch.
    public static func buildLimitedAvailability<Content>(_ content: Content) -> AnyView where Content : View
}

@CommandsBuilder

/// Constructs command sets from multi-expression closures. Like `ViewBuilder`,
/// it supports up to ten expressions in the closure body.
/// 从多表达式闭包构造命令集。像“ViewBuilder”,
/// 它在闭包体中最多支持10个表达式。
@available(iOS 14.0, macOS 11.0, *)
@available(tvOS, unavailable)
@available(watchOS, unavailable)
@_functionBuilder public struct CommandsBuilder {

    /// Builds an empty command set from an block containing no statements.
    public static func buildBlock() -> EmptyCommands

    /// Passes a single command group written as a child group through
    /// modified.
    public static func buildBlock<Content>(_ content: Content) -> Content where Content : Commands
}

@available(iOS 14.0, macOS 11.0, *)
@available(tvOS, unavailable)
@available(watchOS, unavailable)
extension CommandsBuilder {
    public static func buildBlock<C0, C1>(_ c0: C0, _ c1: C1) -> some Commands where C0 : Commands, C1 : Commands
}