如何在 SwiftUI 中限制 FetchRequest 中的结果数量

Question

FetchedResults制作FetchRequestCoreData时如何限制检索到的大小？

struct ContentView: View {
    var fetchRequest:FetchRequest<Kana>

    init(){
        fetchRequest = FetchRequest<Kana>(entity: Kana.entity(), sortDescriptors: [], predicate: NSPredicate(format: "alphabet == %@", "hiragana"))
    }

    var body: some View {
        List{
            Text("10 Kanas")
            // Display 10 Kanas
        }
    }
}

Answer 1

您需要创建FetchRequest与NSFeatchRequest使用相应的初始化器，如下图所示

init() {
    let request: NSFetchRequest<Kana> = Kana.fetchRequest()
    request.fetchLimit = 10
    request.predicate = NSPredicate(format: "alphabet == %@", "hiragana")
    fetchRequest = FetchRequest<Kana>(fetchRequest: request)
}