How to read widgetRenderingMode and other environmentVariants from an IntentTimelineProvider context-CodePudding

I'm trying to ascertain the widgetRenderingMode and other context info from a widget timeline generator, but I see a weird build error with this code:

 func getTimeline(for configuration: AccessoryOptionsIntent, in context: Context, completion: @escaping (Timeline<AccessoryEntry>) -> Void) {
        
        if #available(iOSApplicationExtension 16.0, *) {
            if let mode: [WidgetRenderingMode] = context.environmentVariants.widgetRenderingMode {
                
            }
        }

Cannot assign to property: 'environmentVariants' is a 'let' constant

How can I determine the rendering mode from the timeline?

CodePudding user response：

You probably meant to read the current rendering mode, which can be read just like any other EnvironmentValues in SwiftUI.

@Environment(\.widgetRenderingMode) var widgetRenderingMode

I'm not sure why your code doesn't compile though. In theory, accessing widgetRenderingMode should compile because TimelineProviderContext.EnvironmentVariants is marked with @dynamicMemberLookup. Your access would be turned into a key path and passed into this subscript:

subscript<T>(dynamicMember keyPath: WritableKeyPath<EnvironmentValues, T>) -> [T]? { get }

which is a read-only subscript and does not involve setting environmentVariant.

TimelineProviderContext.EnvironmentVariants does have another subscript that does work for me:

subscript<T>(keyPath: WritableKeyPath<EnvironmentValues, T>) -> [T]? { get }

You can use it like this:

if let mode = context.environmentVariants[\.widgetRenderingMode] {
    
}