发动机

用于开发 SwiftUI 框架和应用程序的性能驱动框架。 可以更轻松地创建习惯性的 API 和视图，这些 API 和视图在 SwiftUI 中感觉自然，而不会牺牲性能。Engine

要求

• 部署目标：iOS 13.0、macOS 10.15、tvOS 13.0 或 watchOS 6.0
• Xcode 14.1+

安装

Xcode 项目

选择 -> -> 并输入 。FileSwift PackagesAdd Package Dependencyhttps://github.com/nathantannar4/Engine

Swift Package Manager 项目

您可以在文件中添加包依赖项：EnginePackage.swift

let package = Package(
    //...
    dependencies: [
        .package(url: "https://github.com/nathantannar4/Engine"),
    ],
    targets: [
        .target(
            name: "YourPackageTarget",
            dependencies: [
                .product(name: "Engine", package: "Engine"),
            ],
            //...
        ),
        //...
    ],
    //...
)

引擎简介

对于一些示例代码的入门，生成并运行包含的“示例”项目。Engine

自定义视图样式

A view style makes developing reusable components easier. This can be especially useful for framework developers who want a component to have a customizable appearance. Look no further than SwiftUI itself. With Engine, you can bring the same functionality to your app or framework by adopting the protocol. Unlike some other styling solutions you made have come across, works without relying on so it is very performant.ViewStyleViewStyleAnyView

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public protocol ViewStyle {
    associatedtype Configuration
    associatedtype Body: View

    @ViewBuilder
    func makeBody(configuration: Configuration) -> Body
}

public protocol ViewStyledView: View {
    associatedtype Configuration
    var configuration: Configuration { get }

    associatedtype DefaultStyle: ViewStyle where DefaultStyle.Configuration == Configuration
    static var defaultStyle: DefaultStyle { get }
}

Variadic Views

A variadic view allows many possibilities with SwiftUI to be unlocked, as it permits a transform of a single view into a collection of subviews. To learn more MovingParts has a great block post on the subject.

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@frozen
public struct VariadicViewAdapter<Source: View, Content: View>: View {

    @inlinable
    public init(
        @ViewBuilder content: @escaping (VariadicView<Source>) -> Content, 
        @ViewBuilder source: () -> Source
    )
}

Availability

Supporting multiple release versions for SwiftUI can be tricky. If a modifier or view is available in a newer release, you have probably used . While this works, it is not performant since will turn this into an . Moreover, the code can become harder to read. For this reason, Engine has and for writing views with a that can be different based on release availability.if #available(...)@ViewBuilderAnyViewVersionedViewVersionedViewModifierbody

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public protocol VersionedView: View where Body == Never {
    associatedtype V4Body: View = V3Body

    @available(iOS 16.0, macOS 13.0, tvOS 16.0, watchOS 9.0, *)
    @ViewBuilder var v4Body: V4Body { get }

    associatedtype V3Body: View = V2Body

    @available(iOS 15.0, macOS 12.0, tvOS 15.0, watchOS 8.0, *)
    @ViewBuilder var v3Body: V3Body { get }

    associatedtype V2Body: View = V1Body

    @available(iOS 14.0, macOS 11.0, tvOS 14.0, watchOS 7.0, *)
    @ViewBuilder var v2Body: V2Body { get }

    associatedtype V1Body: View = EmptyView

    @ViewBuilder var v1Body: V1Body { get }
}

Static Conditionals

Should you ever have a modifier or view that is conditional upon a static flag, Engine provides and . A great example is a view or modifier is different depending on the user interface idiom. When you use an in a , the Swift compiler doesn’t know that the condition is static. So SwiftUI will need to be ready for the condition to change, which can hinder performance needlessly if you know the condition is static.StaticConditionalContentStaticConditionalModifierif/else@ViewBuilder

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public protocol StaticCondition {
    static var value: Bool { get }
}

@frozen
public struct StaticConditionalContent<
    Condition: StaticCondition,
    TrueContent: View,
    FalseContent: View
>: View {
    
    @inlinable
    public init(
        _ : Condition.Type = Condition.self,
        @ViewBuilder then: () -> TrueContent,
        @ViewBuilder else: () -> FalseContent
    )
}

@frozen
public struct StaticConditionalModifier<
    Condition: StaticCondition,
    TrueModifier: ViewModifier,
    FalseModifier: ViewModifier
>: ViewModifier {

    @inlinable
    public init(
        _ : Condition.Type = Condition.self,
        @ViewModifierBuilder then: () -> TrueModifier,
        @ViewModifierBuilder else: () -> FalseModifier
    )
}

License

Distributed under the BSD 2-Clause License. See for more information.LICENSE.md

GitHub

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