WWDC Notes

Widgets Code-along, part 2: Alternate timelines

Show Apple's description.
Our code-along continues as we help our widget rewrite the future and travel into an alternate timeline. Continue where you left off from Part 1, or traverse time and space and begin with the Part 2 starter project to jump right into the action. Find out how you can integrate system intelligence into your widgets to help them dynamically change at different points during the day and surface the most relevant information. Explore core timeline concepts, support multiple widget families, and learn how to make your widget configurable. Once you’ve helped your widget find its place in time, move on to the third and final part of the Widgets Code-along to discover advanced widget concepts and timelines.

Families

Three available families:

When drawing our widget, we can detect which widget family we're drawing the .widgetFamily environment variable:

struct WWDCNotesWidgetEntryView : View {
  var entry: Provider.Entry
  @Environment(\.widgetFamily) var family

  var body: some View {
    Text(entry.date, style: .time)
  }
}

Timelines

The IntentTimelineProvider is the engine of the widget.

When our TimelineProvider is asked to provide a Timeline, we also need to define our reload policy:

  • atEnd: tells WidgetKit to request a new timeline only after the date of the last entry has passed
  • after(date: Date): tells WidgetKit to request a new timeline only after a specified date
  • Never: tells WidgetKit to never request a new timeline, the app will let WidgetKit know when a new timeline is available.

When creating a timeline, we can also set an optional relevance to each entry, TimelineEntryRelevance, in order to let the system know how important each entry is (compared to other entries from the same widget).

Configuration

WidgetKit configuration is driven by SiriKit, the core technology for configuration is a custom INIntents.

For more, refer to session Add configuration and intelligence to your widgets.

To create a new configuration/intent go to File > New File and choose SiriKit Intent Definition File..

This will create a .intentdefinition file whose target membership must be both the widget target and the main app.

After opening this file create a new intent and:

  • set its category to View
  • check the is elegible for widgets option
  • add your configuration parameters

Once the intent/configuration setup is complete, we need to go back to our widget definition and make sure that our widget configuration is a IntentConfiguration, the difference from the default StaticConfiguration (beside that one allows configuration and the other doesn't) is that IntentConfiguration requires an extra intent parameter where we can define set our intent as if it was a class/struct:

@main
struct WWDCNotesWidget: Widget {
  private let kind: String = "WWDCNotesWidget"

  public var body: some WidgetConfiguration {
    IntentConfiguration(
      kind: kind, 
      intent: WWDCNotesCustomIntent.self, // this is our intent
      provider: Provider(), 
      placeholder: PlaceholderView()
    ) { entry in
      WWDCNotesWidgetEntryView(entry: entry)
    }
    .configurationDisplayName("My Widget")
    .description("This is an example widget.")
  }
}

If we use an IntentConfiguration, we also need to make sure that we declare a IntentTimelineProvider instead of a TimelineProvider, the difference with the base TimelineProvider is that both the snapshot(for:with:completion:) and timeline(for:with:completion:) functions have an extra configuration parameters (that matched our intent type)

struct Provider: IntentTimelineProvider {
  typealias Intent = WWDCNotesCustomIntent
  public typealias Entry = SimpleEntry
  
  public func snapshot(
    for configuration: WWDCNotesCustomIntent, // extra parameter
    with context: Context, 
    completion: @escaping (SimpleEntry) -> Void
  ) {
      ...
  }

  public func timeline(
    for configuration: WWDCNotesCustomIntent, // extra parameter
    with context: Context, 
    completion: @escaping (Timeline<Entry>) -> Void
  ) {
    ...
  }
}

Deep linking

Widgets do not have animation or custom interactions, but we can deep-link from our widget into our app:

  • .systemSmall widgets are one large tap area
  • .systemMedium and .systemLarge can use the new SwiftUI Link API to create tappable zones within the widget.

To add deep links into our app, we use the .widgeturl(_:) modifier.

In our app then we apply the new .onOpenURL(perform:) to the right view to manage deeplinks.

Missing anything? Corrections? Contributions are welcome 😃

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Written by

zntfdr

Federico Zanetello

Federico Zanetello is an iOS Engineer with strong passion for Swift, minimalism, and design. When he’s not busy automating things, he can be found writing at fivestars.blog and/or playing with the latest shiny toys.