How to convert MKMapItem to binary data to store in Core Data?

Question

I am want to store MKMapItem that was previously found by MKLocalSearch in Core Data so I can show it to the user when the view loads in the future.

What I have is I have created an Entity in xcdatamodeld file and created a binaryData attribute called mapItem.

I want to encode the found MKMapItem to binary data and store it in core data.

Later I want to decode it to an MKMapItem.

I noticed that MKMapItem has an encode method that needs an NSCoder object.

I am not super familiar with NSCoding so any help will be appreciated.

I can always save the string attributes from MKMapItem in core data by creating multiple attributes for the entity, but I was wondering if there was an easy way.

Thanks!

Wouldn't it be easier if you just save the location with Core Data so that you can reconstruct the corresponding MKMapItem object with the former? — El Tomato, Mar 05 '19 at 23:34

score 1 · Accepted Answer · answered Mar 22 '19 at 23:09

I figured it out. To store the MapItem in Core Data, I used the NSKeyedArchiver. It encodes the MapItem into Data and to decode, you can use the NSKeyedUnarchiver

func saveMapItems(_ mapItems: [MKMapItem]) {
    do {
        let data = try NSKeyedArchiver.archivedData(withRootObject: mapItems, requiringSecureCoding: false)
        let request: NSFetchRequest<RecentSearchLocation> = RecentSearchLocation.fetchRequest()
        if
            let recentLocations = try? coreDataManager.persistentContainer.viewContext.fetch(request).first,
            let location = recentLocations {
            location.mapItems = data
        } else {
            let location = RecentSearchLocation(context: coreDataManager.persistentContainer.viewContext)
            location.mapItems = data
        }
    } catch {
        print("Can't encode data: \(error)")
    }
    do {
        try coreDataManager.persistentContainer.viewContext.save()
    } catch {
        print("Error saving context \(error)")
    }
}

To decode I did this

func readMapItems() -> [MKMapItem] {
        let request: NSFetchRequest<RecentSearchLocation> = RecentSearchLocation.fetchRequest()
        guard
            let data = try? coreDataManager.persistentContainer.viewContext.fetch(request).first?.mapItems,
            let dataToUnarchive = data else {
                print("Cannot get mapItems from coreData data")
                return []
        }
        do {
            guard let recentSearchLocations = try NSKeyedUnarchiver.unarchiveTopLevelObjectWithData(dataToUnarchive) as? [MKMapItem] else {
                return []
            }
            return recentSearchLocations
        } catch {
            print("Error unarchiving mapItems, \(error)")
            return []
        }
    }

How to convert MKMapItem to binary data to store in Core Data?

1 Answers1