ViewDescription.md

ViewDescription

View Descriptions contain all the information needed to create an instance of a native UIView. Importantly, view descriptions do not contain instances of a view. They only contain the data necessary to instantiate or update a view.

Creating a view description

UILabel.describe { config in
    config[\.text] = "Hello, world"
    config[\.textColor] = .orange
}

// Or...

ViewDescription(UILabel.self) { config in
    config[\.text] = "Hello, world"
    config[\.textColor] = .orange
}

In both cases, the last argument is a closure responsible for configuring the view type. The argument passed into the closure is a value of the type ViewDescription.Configuration

extension ViewDescription {
    public struct Configuration<View: UIView> {}
}

Specifying how the view should be instantiated

UITableView.describe { config in
    config.builder = {
        UITableView(frame: .zero, style: .plain)
    }
}

Assigning values to properties

UIView.describe { config in
    config[\.backgroundColor] = .magenta
}

Applying arbitrary update logic

UIView.describe { config in
    config.apply { view in
        view.layer.masksToBounds = true
    }
}

Specifying a subview that should contain any view-backed child elements

private class MyCustomView: UIView {
    let mySubview = UIView()
}

MyCustomView.describe { config in
    config.contentView = { myCustomView in
        myCustomView.mySubview
    }
}

Specifying transitions

UIView.describe { config in
    config.layoutTransition = .specific(AnimationAttributes())
    config.appearingTransition = .scale
    config.disappearingTransition = .fade
}