如何在 SwiftUI 中将 @FetchRequest 与新的可搜索修饰符一起使用？

Question

是否可以将新的 searable 与 @FetchRequest 结合使用？

我有这样的代码：

struct FooListView: View {
    @Environment(\.managedObjectContext) private var viewContext
    
    @FetchRequest(
        sortDescriptors: [NSSortDescriptor(keyPath: \Foo.name, ascending: true)],
        animation: .default)
    private var items: FetchedResults<Foo>

    @State var searchText = ""

    var body: some View {
        NavigationView {
            List {
                ForEach(items) { item in
                    NavigationLink(destination: FooView(Foo: item)) {
                        Text(item.wrappedName)
                    }
                }
                .onDelete(perform: deleteItems)
            }
            .searchable(text: $searchText)
            .navigationTitle("Foos")
        }
    }
}

在这个简单的例子中，我想使用 searchText 来欺骗我的 FetchedResults。

Answer 1

WWDC 2021 将核心数据并发带到 Swift，SwiftUI 就在 21:33

分钟左右有一个很好的例子

https://developer.apple.com/wwdc21/10017

struct ContentView: View {
    @FetchRequest(sortDescriptors: [SortDescriptor(\Quake.time, order: .reverse)])
    private var quakes: FetchedResults<Quake>

    @State private var searchText = ""
    var query: Binding<String> {
        Binding {
            searchText
        } set: { newValue in
            searchText = newValue
            quakes.nsPredicate = newValue.isEmpty
                           ? nil
                           : NSPredicate(format: "place CONTAINS %@", newValue)
        }
    }

    var body: some View {
        List(quakes) { quake in
            QuakeRow(quake: quake)
        }
        .searchable(text: query)
    }
}

Answer 2

我不会用额外的绑定使它过于复杂。为什么不只在 searchText 上使用 onChange 修饰符。

struct ContentView: View {
    @FetchRequest(sortDescriptors: [SortDescriptor(\Quake.time, order: .reverse)])
    private var quakes: FetchedResults<Quake>
    
    @State private var searchText = ""
    
    var body: some View {
        List(quakes) { quake in
            QuakeRow(quake: quake)
        }
        .searchable(text: $searchText)
        .onChange(of: searchText) { newValue in
            quakes.nsPredicate = newValue.isEmpty ? nil : NSPredicate(format: "place CONTAINS %@", newValue)
        }
    }
}

如何在 SwiftUI 中将 @FetchRequest 与新的可搜索修饰符一起使用？

How to use a @FetchRequest with the new searchable modifier in SwiftUI?

searchable

swift

swiftui

fetchrequest