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SOLVED: FetchLimit Core Data

Forums > SwiftUI
@daniellee152  

How can I limit numer of quotes in my fetch request, for example 100 quotes. I know it might use fetch limit liked request.fetchlimit = 100. However, I get the error NSFetchRequest cannot convert to FetchRequest. Any ideas how to get this one done?


extension Quote : Identifiable {
  @NSManaged var content : String
  @NSManaged var author : String?
  @NSManaged var category : String
  @NSManaged var isLiked : Bool

  static func basicFetchRequest() -> FetchRequest<Quote> {
    FetchRequest(entity: Quote.entity(), sortDescriptors: [])
  }
}

In Content View

  let fetchRequest = Quote.basicFetchRequest()
  var quotes : FetchedResults<Quote>  {
    fetchRequest.wrappedValue
  }

 ``

3      

@roosterboy  HWS+

You would use a different initializer for the FetchRequest, like so:

static func basicFetchRequest() -> FetchRequest<Quote> {
    let request = fetchRequest()
    request.fetchLimit = 100
    //set up any predicates or sort descriptors
    return FetchRequest(fetchRequest: request)
}

4      

@daniellee152  

it still give the errors

Cannot convert return expression of type 'FetchRequest<NSFetchRequestResult>' to return type 'FetchRequest<Quote>'

3      

@roosterboy  HWS+

Ah, right, that's because FetchRequest is only available in a SwiftUI View, since it uses the managedObjectContext property from the environment, which is only available in a View. So you need to construct an NSFetchRequest within your managed object subclass and pass it to the FetchRequest within your View.

In your managed object subclass:

static func fetchRequestLimit100() -> NSFetchRequest<Quote> {
    let request: NSFetchRequest<Quote> = Quote.fetchRequest()
    request.fetchLimit = 100
    //set up any predicates or sort descriptors
    return request
}

And then in your View:

@FetchRequest(fetchRequest: Quote.fetchRequestLimit100)
var quotes: FetchedResults<Quote>

5      

@daniellee152  

Thank you @roosterboy, it works perfectly

3      

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