How do I make a better performing scrolling view

Asked on 2025-06-24

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To create a better-performing scrolling view in SwiftUI, you can leverage several techniques and improvements introduced in recent WWDC sessions:

  1. Use Lazy Stacks: SwiftUI's lazy stacks, such as LazyVStack, only create and render views for items that are currently visible or about to scroll into view. This can significantly reduce CPU usage and improve performance, especially for large data sets. This approach is highlighted in the session Profile and optimize power usage in your app.

  2. Idle Prefetching: SwiftUI and UIKit use a technique called idle prefetching, which takes advantage of idle time after rendering the current frame to prepare the next frame. This helps reduce the chance of dropping frames while scrolling. This feature is now available on macOS as well, as mentioned in the Platforms State of the Union.

  3. Optimize View Updates: Avoid unnecessary view updates that can cause performance issues. Use the new SwiftUI performance instrument in Xcode to diagnose and fix long view body updates, as discussed in the session Optimize SwiftUI performance with Instruments.

  4. Custom Visual Effects: You can create custom scroll effects using SwiftUI's scroll transition and visual effect modifiers. These allow you to change visual properties based on the view's position and size in a performant way. This is covered in the session Create custom visual effects with SwiftUI.

By implementing these techniques, you can enhance the performance and visual appeal of your scrolling views in SwiftUI.