Swiftui CoreData和FetchRequest,与ForEach和;无法调用初始值设定项";
我只是迁移到使用CoreDate而不是简单的集合。我正在使用iOS13 beta 8和Xcode11 beta 6Swiftui CoreData和FetchRequest,与ForEach和;无法调用初始值设定项";,swiftui,ios13,xcode11,Swiftui,Ios13,Xcode11,我只是迁移到使用CoreDate而不是简单的集合。我正在使用iOS13 beta 8和Xcode11 beta 6 struct BeaconList: View { @Environment(\.managedObjectContext) var managedObjectContext @FetchRequest(fetchRequest: fetchRequest(), animation: nil) var beacons: FetchedResults<Beaco
struct BeaconList: View {
@Environment(\.managedObjectContext) var managedObjectContext
@FetchRequest(fetchRequest: fetchRequest(), animation: nil) var beacons: FetchedResults<Beacon>
static func fetchRequest() -> NSFetchRequest<Beacon> {
let request: NSFetchRequest<Beacon> = Beacon.fetchRequest()
request.sortDescriptors = [NSSortDescriptor(key: "id", ascending: true)]
return request
}
func buildView(name: String, beacons: [Beacon]) -> AnyView {
return AnyView (
Section(header: Text(name)) {
ForEach(beacons) { beacon in
BeaconListEntry(beacon: beacon)
}
}
)
}
var body: some View {
TabView {
NavigationView {
List {
buildView(name: "MY BEACONS", beacons: beacons.filter { $0.isActive })
}
.navigationBarTitle("Beacons")
.listStyle(GroupedListStyle())
.navigationBarItems(trailing: addButton)
}
.tabItem {
Image(systemName: "antenna.radiowaves.left.and.right")
Text("Beacons")
}
}
}
(请忽略强制展开,仅用于测试目的)
当我在重写之前将其用于集合时,它起了作用,但现在我明白了这一点
Cannot invoke initializer for type 'ForEach<_, _, _>' with an argument list of type '([Beacon], @escaping (Binding<Beacon>) -> BeaconListEntry)'
无法使用类型为“([Beacon],@escaping(Binding)->BeaconListEntry)”的参数列表调用类型为“ForEach”的初始值设定项
及
1。“ForEach”的重载存在于这些部分匹配的参数列表中:(数据,内容:@escaping(Data.Element)->content),(范围,内容:@escaping(Int)->content)
知道去哪里找吗?这是使用
FetchedResults
的正确方法吗?BeaconListEntry初始值设定项要求参数具有类型绑定
,因此您应该按如下方式修改调用:
struct BeaconListEntry : View {
@Binding var beacon: Beacon
var body: some View {
HStack {
Text(verbatim: beacon.name!)
}
}
}
BeaconListEntry(beacon: .constant(beacon))
BeaconListEntry(beacon: .constant(beacon))