# Preview A base type that preview macros use to create previews. ``` @MainActor struct Preview ``` ## Overview Frameworks like SwiftUI and WidgetKit define initializers for this type, along with framework-specific preview macros that rely on this type. You don’t use this type directly. Instead, use one of the preview macros, like . ## Topics ### Creating a SwiftUI preview [`init(String?, traits: PreviewTrait..., body: () -> any View)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:body:)-8pemr) Creates a preview of a SwiftUI view. [`init(String?, traits: PreviewTrait..., body: () -> any View, cameras: () -> [PreviewCamera])`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:body:cameras:)) Creates a preview of a SwiftUI view using the specified traits and custom viewpoints. [`init(String?, immersionStyle: some ImmersionStyle, traits: PreviewTrait..., body: () -> any View, cameras: () -> [PreviewCamera])`](/documentation/DeveloperToolsSupport/Preview/init(_:immersionStyle:traits:body:cameras:)) Creates a preview of a SwiftUI view in an immersive space with custom viewpoints. [`init(String?, windowStyle: some WindowStyle, traits: PreviewTrait..., body: () -> any View, cameras: () -> [PreviewCamera])`](/documentation/DeveloperToolsSupport/Preview/init(_:windowStyle:traits:body:cameras:)) Creates a preview of a SwiftUI view in a window with custom viewpoints. ### Creating a preview of a widget [`init(String?, as: ActivityPreviewViewKind, using: Attributes, widget: () -> some Widget, contentStates: () async -> [Attributes.ContentState])`](/documentation/DeveloperToolsSupport/Preview/init(_:as:using:widget:contentStates:)) Creates a preview of a live activity widget. [`init(String?, as: WidgetFamily, using: Provider.Intent, widget: () -> some Widget, timelineProvider: () -> Provider)`](/documentation/DeveloperToolsSupport/Preview/init(_:as:using:widget:timelineProvider:)-1if5u) Creates a preview of a widget with an `AppIntent` configuration. [`init(String?, as: WidgetFamily, using: Provider.Intent, widget: () -> some Widget, timelineProvider: () -> Provider)`](/documentation/DeveloperToolsSupport/Preview/init(_:as:using:widget:timelineProvider:)-5335n) Creates a preview of a widget with an `INIntent` configuration. [`init(String?, as: WidgetFamily, widget: () -> some Widget, timeline: () async -> [any TimelineEntry])`](/documentation/DeveloperToolsSupport/Preview/init(_:as:widget:timeline:)) Creates a preview of a timeline-style widget. [`init(String?, as: WidgetFamily, widget: () -> some Widget, timelineProvider: () -> some TimelineProvider)`](/documentation/DeveloperToolsSupport/Preview/init(_:as:widget:timelineProvider:)) Creates a preview of a widget with a static configuration. ### Creating an AppKit preview [`init(String?, traits: PreviewTrait..., body: () -> NSView)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:body:)-158mk) Creates a preview of an NSView. [`init(String?, traits: PreviewTrait..., body: () -> NSViewController)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:body:)-2viaf) Creates a preview of an NSViewController. ### Getting preview traits [`enum ViewTraits`](/documentation/DeveloperToolsSupport/Preview/ViewTraits) Traits that apply to previews of views and view controllers. ### Initializers [`init(String?, traits: PreviewTrait..., arguments: [T], body: (T) -> any View)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:arguments:body:)-1xqo1) Creates a group of previews of a SwiftUI view. [`init(String?, traits: PreviewTrait..., arguments: [T], body: (T) -> UIViewController)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:arguments:body:)-287km) [`init(String?, traits: PreviewTrait..., arguments: [T], body: (T) -> UIView)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:arguments:body:)-3q0i9) [`init(String?, traits: PreviewTrait..., arguments: [T], body: (T) -> NSViewController)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:arguments:body:)-4ieth) Creates a group of previews of an NSViewController. [`init(String?, traits: PreviewTrait..., arguments: [T], body: (T) -> NSView)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:arguments:body:)-5cb4o) Creates a group of previews of an NSView. [`init(String?, traits: PreviewTrait..., body: () -> UIView)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:body:)-3i54d) [`init(String?, traits: PreviewTrait..., body: () -> UIViewController)`](/documentation/DeveloperToolsSupport/Preview/init(_:traits:body:)-941vb) [`init(String?, widget: () -> some Widget, relevanceEntries: () async -> [Entry])`](/documentation/DeveloperToolsSupport/Preview/init(_:widget:relevanceEntries:)) Creates a preview of a relevance-driven widget. [`init(String?, widget: () -> some Widget, relevanceProvider: () -> Provider)`](/documentation/DeveloperToolsSupport/Preview/init(_:widget:relevanceProvider:)) Creates a preview of a relevance-driven widget. [`init(String?, widget: () -> some Widget, relevanceProvider: () -> Provider, relevance: () async -> WidgetRelevance)`](/documentation/DeveloperToolsSupport/Preview/init(_:widget:relevanceProvider:relevance:)) Creates a preview of a relevance-driven widget. ## Relationships ### Conforms To [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`Sendable`](/documentation/Swift/Sendable) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)