https://github.com/lumisilk/pinnedscrollview

Pinned views on SwiftUI without using LazyVStack
https://github.com/lumisilk/pinnedscrollview

Last synced: about 2 months ago
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Pinned views on SwiftUI without using LazyVStack

• Host: GitHub
• URL: https://github.com/lumisilk/pinnedscrollview
• Owner: Lumisilk
• License: mit
• Created: 2023-11-14T04:37:39.000Z (about 1 year ago)
• Default Branch: main
• Last Pushed: 2024-03-12T03:14:29.000Z (11 months ago)
• Last Synced: 2024-03-12T04:27:13.541Z (11 months ago)
• Language: Swift
• Size: 12.7 KB
• Stars: 4
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
## PinnedScrollView

PinnedScrollView is a tiny SwiftUI library that helps you pin any view in a scrollview like a header, without using  `LazyVStack` and `Section`.



## Usage

```swift

var body: some View {

    ScrollView {

        VStack(spacing: 0) {

            ForEach(0..<20) { _ in

                Text("Header")

                    .pinned() // 1

                

                Text("Some content text")

            }

        }

    }

    .pinnedScrollView() // 2

}

```

1. Add `.pinned()` modifier to the view you want to pin within the scrollview

2. Add `.pinnedScrollView()` modifier to the corresponding scrollview

That's it!

#### Optional observation

You can also provide a optional closure `onReachedTop: (Bool) -> ()` to the `pinned` modifier if you want to get a notification when the pinned state changed.

```swift

@State private var isHeaderReachedTop = false

// ...

Text("Header" + (isHeaderReachedTop ? " Reached" : ""))

    .pinned { isReachedTop in

        isHeaderReachedTop = isReachedTop

    }

```

## Limitation

PinnedScrollView requires iOS/iPadOS 14.0.

PinnedScrollView only supports vertical `ScrollView` and doesn't support horizontal `ScrollView` or the `List` view.

## Installation

Use [Swift Package Manager](https://developer.apple.com/documentation/xcode/adding-package-dependencies-to-your-app) to add PinnedScrollView to your project.

`https://github.com/Lumisilk/PinnedScrollView.git`

## License

This package is licensed under the MIT open-source license.

## Inspiration

The implementation of PinnedScrollView was inspired by objc.io's course on [Sticky Headers for Scroll Views](https://talk.objc.io/episodes/S01E333-sticky-headers-for-scroll-views).

Unlike the original implementation from objc.io, which uses `PreferenceKey` to coordinate the frames of headers and can lead to performance bottlenecks, PinnedScrollView use `onChange` to efficiently record the frames of headers.

Additionally, PinnedScrollView use Combine's `debounce` and publisher to minimize the re-evaluation count of the headers' body, aiming to optimize performance.

Special thanks to [@auramagi](https://github.com/auramagi) for the algorithm suggestions.