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If your app has any data or content, you will probably want to implement spotlight indexing, so that users can conveniently search in spotlight.

1. Create the searchable items

Let’s start with creating CSSearchableItem for a model in the app. We use the model station as an example.

import CoreSpotlight
import MobileCoreServices

func createSearchableItem(_ station: Station) -> CSSearchableItem {
    let attributeSet = CSSearchableItemAttributeSet(itemContentType: kUTTypeData as String)
    attributeSet.title = station.name
    attributeSet.contentDescription = station.description
    attributeSet.thumbnailData = station.logo.pngData()
    return CSSearchableItem(uniqueIdentifier: station.id, domainIdentifier: "station", attributeSet: attributeSet)
}

The above is the minimal data that you are recommended to provide. You could provide more metadata.

2. Index them all

func indexAll() {
    let stations = ...
    let items = stations.map { createSearchableItem($0) }
    CSSearchableIndex.default().indexSearchableItems(items) {
        if let error = $0 {
            logError(error.localizedDescription)
        }
    }
}

Using CSSearchableIndex, you add your items to the index. Do a search, and you should see in spotlight results.

PITFALL: Simulator might not work, so try on a real device.

3. Handle when tap on an item

In your app delegate, implement application:continueUserActivity:restorationHandler:, the user activity handoff method.

func application(_ application: UIApplication, continue userActivity: NSUserActivity, restorationHandler: @escaping ([UIUserActivityRestoring]?) -> Void) -> Bool {
    if userActivity.activityType == CSSearchableItemActionType {
        if let identifier = userActivity.userInfo? [CSSearchableItemActivityIdentifier] as? String {
            // Handle it. Navigate to a certain screen, or perform certain action.
            return true
        }
    }
    return false
}

The same app delegate method is used for universal link too.

4. Maintain the index

To update an item, use indexSearchableItems() with the same uniqueIdentifier.

To delete, you can use deleteSearchableItemsWithIdentifiers and other methods.