# View fundamentals Define the visual elements of your app using a hierarchy of views. ## Overview Views are the building blocks that you use to declare your app’s user interface. Each view contains a description of what to display for a given state. Every bit of your app that’s visible to the user derives from the description in a view, and any type that conforms to the [`View`](/documentation/SwiftUI/View) protocol can act as a view in your app.  Compose a custom view by combining built-in views that SwiftUI provides with other custom views that you create in your view’s [`body`](/documentation/SwiftUI/View/body-8kl5o) computed property. Configure views using the view modifiers that SwiftUI provides, or by defining your own view modifiers using the [`ViewModifier`](/documentation/SwiftUI/ViewModifier) protocol and the [`modifier(_:)`](/documentation/SwiftUI/View/modifier(_:)) method. ## Topics ### Creating a view [Declaring a custom view](/documentation/SwiftUI/Declaring-a-Custom-View) Define views and assemble them into a view hierarchy. [Wishlist: Planning travel in a SwiftUI app](/documentation/SwiftUI/wishlist-planning-travel-in-a-swiftui-app) Build a travel planning app that organizes trips into collections and tracks activity completion. [`View`](/documentation/SwiftUI/View) A type that represents part of your app’s user interface and provides modifiers that you use to configure views. [`ContentBuilder`](/documentation/SwiftUI/ContentBuilder) A custom parameter attribute that constructs views and other content types from closures. [`ViewBuilder`](/documentation/SwiftUI/ViewBuilder) A custom parameter attribute that constructs views from closures. ### Modifying a view [Configuring views](/documentation/SwiftUI/Configuring-Views) Adjust the characteristics of a view by applying view modifiers. [Reducing view modifier maintenance](/documentation/SwiftUI/Reducing-View-Modifier-Maintenance) Bundle view modifiers that you regularly reuse into a custom view modifier. [`modifier(_:)`](/documentation/SwiftUI/View/modifier(_:)) Applies a modifier to a view and returns a new view. [`ViewModifier`](/documentation/SwiftUI/ViewModifier) A modifier that you apply to a view or another view modifier, producing a different version of the original value. [`EmptyModifier`](/documentation/SwiftUI/EmptyModifier) An empty, or identity, modifier, used during development to switch modifiers at compile time. [`ModifiedContent`](/documentation/SwiftUI/ModifiedContent) A value with a modifier applied to it. [`EnvironmentalModifier`](/documentation/SwiftUI/EnvironmentalModifier) A modifier that must resolve to a concrete modifier in an environment before use. [`ManipulableModifier`](/documentation/SwiftUI/ManipulableModifier) [`ManipulableResponderModifier`](/documentation/SwiftUI/ManipulableResponderModifier) [`ManipulableTransformBindingModifier`](/documentation/SwiftUI/ManipulableTransformBindingModifier) [`ManipulationGeometryModifier`](/documentation/SwiftUI/ManipulationGeometryModifier) [`ManipulationGestureModifier`](/documentation/SwiftUI/ManipulationGestureModifier) [`ManipulationUsingGestureStateModifier`](/documentation/SwiftUI/ManipulationUsingGestureStateModifier) [`Manipulable`](/documentation/SwiftUI/Manipulable) A namespace for various manipulable related types. ### Responding to view life cycle updates [`onAppear(perform:)`](/documentation/SwiftUI/View/onAppear(perform:)) Adds an action to perform before this view appears. [`onDisappear(perform:)`](/documentation/SwiftUI/View/onDisappear(perform:)) Adds an action to perform after this view disappears. ### Assigning tasks [`task(id:name:executorPreference:priority:file:line:_:)`](/documentation/SwiftUI/View/task(id:name:executorPreference:priority:file:line:_:)) Adds a task to perform before this view appears or when a specified value changes. [`task(id:name:priority:file:line:_:)`](/documentation/SwiftUI/View/task(id:name:priority:file:line:_:)) Adds a task to perform before this view appears or when a specified value changes. [`task(name:executorPreference:priority:file:line:action:)`](/documentation/SwiftUI/View/task(name:executorPreference:priority:file:line:action:)) Adds an asynchronous task to perform before this view appears. [`task(name:priority:file:line:_:)`](/documentation/SwiftUI/View/task(name:priority:file:line:_:)) Adds an asynchronous task to perform before this view appears. ### Managing the view hierarchy [`id(_:)`](/documentation/SwiftUI/View/id(_:)) Binds a view’s identity to the given proxy value. [`tag(_:includeOptional:)`](/documentation/SwiftUI/View/tag(_:includeOptional:)) Sets the unique tag value of this view. [`equatable()`](/documentation/SwiftUI/View/equatable()) Prevents the view from updating its child view when its new value is the same as its old value. ### Supporting content types [`EmptyContent`](/documentation/SwiftUI/EmptyContent) Content which contains nothing. [`TupleContent`](/documentation/SwiftUI/TupleContent) Content created from a tuple of content to be treated as siblings. ### Supporting view types [`AnyView`](/documentation/SwiftUI/AnyView) A type-erased view. [`EmptyView`](/documentation/SwiftUI/EmptyView) A view that doesn’t contain any content. [`EquatableView`](/documentation/SwiftUI/EquatableView) A view type that compares itself against its previous value and prevents its child updating if its new value is the same as its old value. [`SubscriptionView`](/documentation/SwiftUI/SubscriptionView) A view that subscribes to a publisher with an action. [`TupleView`](/documentation/SwiftUI/TupleView) A View created from a swift tuple of View values. --- 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)