Micro

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For demo, check DemoMicro

Read more

• How to build SwiftUI style UICollectionView data source in Swift
• A better way to update UICollectionView data in Swift with diff framework

Description

Most of the time, we want to apply model data to cell with smart diffing. Micro provides type safe SwiftUI style data source for UICollectionView, with super fast diffing powered by DeepDiff. Just declare a State with SwiftUI style forEach and Micro will reload with animated diffing

struct Blog: DiffAware {}
class BlogCell: UICollectionViewCell {}

let dataSource = DataSource(collectionView: collectionView)
dataSource.state = State {
    ForEach(blogs) { blog in
        Cell<BlogCell>() { context, cell in
            cell.nameLabel.text = blog.name
        }
        .onSelect { context in 
            print("cell at index \(context.indexPath.item) is selected")
        }
        .onSize { context in 
            CGSize(
                width: context.collectionView.frame.size.width, 
                height: 40
            )
        }
    }
}

The above uses Swift 5.1 function builder syntax, which uses forEach method under the hood. You can also do like below with forEach method.

dataSource.state = forEach(blogs) { blog in
    Cell<BlogCell>() { context, cell in
        cell.nameLabel.text = blog.name
    }
    .onSelect { context in 
        print("cell at index \(context.indexPath.item) is selected")
    }
    .onSize { context in 
        CGSize(
            width: context.collectionView.frame.size.width, 
            height: 40
        )
    }
}

Features

• Supports iOS 8+
• Declare in type safe manner with forEach
• context provides additional information, like UICollectionView and IndexPath
• Automatic reload with smart diffing whenever state is set
• By default, diffing is animated, you can use dataSource.reload(newState:isAnimated:completion) to specify animated and completion

Advanced

Animate reloading

By default, when you set state on DataSource, animated diffing is performed. If you want to set animated property and to listen to completion event, you can use reload method

dataSource.reload(
    newState: newState,
    isAnimated: false,
    completion: { finished in
        print("reloade is finished")
    }
)

Complex model with multiple cell types

You can declare different Cell in forEach with different kinds of cell.

struct Movie: DiffAware {
    enum Kind: Equatable {
        case show(String)
        case loading
        case ad
    }

    let diffId = UUID()
    let kind: Kind

    static func compareContent(_ a: Movie, _ b: Movie) -> Bool {
        return a.kind == b.kind
    }
}

class MovieCell: UICollectionViewCell {
    let nameLabel: UILabel = .init()
}

class LoadingCell: UICollectionViewCell {}

class AdCell: UICollectionViewCell {}

let layout = UICollectionViewFlowLayout()
let collectionView = UICollectionView(frame: .zero, collectionViewLayout: layout)
let dataSource = DataSource(collectionView: collectionView)
collectionView.dataSource = dataSource
collectionView.delegate = dataSource

let movies: [Movie] = [
    Movie(kind: .show("Titanic")),
    Movie(kind: .show("Batman")),
    Movie(kind: .loading),
    Movie(kind: .ad)
]

dataSource.state = forEach(movies) { movie in
    switch movie.kind {
    case .show(let name):
        return Cell<MovieCell>() { context, cell in
            cell.nameLabel.text = name
        }
        .onSelect { _ in

        }
        .onDeselect { _ in

        }
        .onWillDisplay { _, _ in

        }
        .onDidEndDisplay { _, _ in

        }
        .onSize { context in
            CGSize(width: context.collectionView.frame.size.width, height: 40)
        }
    case .loading:
        return Cell<LoadingCell>()
    case .ad:
        return Cell<AdCell>()
    }
}

Customize with subclass

DataSource is completely overridable, if you want to customize any methods, just subclass DataSource, override methods and access its state.models

class CustomDataSource: DataSource {
    override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let blog = state.models[indexPath.item] as? Blog
        print(blog)
    }
}

Installation

Micro is also available through Swift Package Manager

.package(url: "https://github.com/onmyway133/Micro", from: "1.2.0")

Author

Khoa Pham, onmyway133@gmail.com

License

Micro is available under the MIT license. See the LICENSE file for more info.