【发布时间】：2021-06-13 01:38:03
【问题描述】：
我正在尝试从我的核心数据中获取实体和属性以显示在一个小部件中并且真的很挣扎。目前我可以获取实体的 ItemCount，但这不是我想要显示的。我希望能够显示我保存在 Core Data 中的字符串和图像。我查看了很多网站，包括 this post，但都没有成功。
我当前的设置有一个用于核心数据的工作应用程序组，它与主应用程序和小部件共享。
这是用于显示实体的 ItemCount 的 Widget.swift 代码：
import WidgetKit
import SwiftUI
import CoreData
private struct Provider: TimelineProvider {
func placeholder(in context: Context) -> SimpleEntry {
SimpleEntry(date: Date())
}
func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> Void) {
let entry = SimpleEntry(date: Date())
completion(entry)
}
func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> Void) {
let midnight = Calendar.current.startOfDay(for: Date())
let nextMidnight = Calendar.current.date(byAdding: .day, value: 1, to: midnight)!
let entries = [SimpleEntry(date: midnight)]
let timeline = Timeline(entries: entries, policy: .after(nextMidnight))
completion(timeline)
}
}
private struct SimpleEntry: TimelineEntry {
let date: Date
}
private struct MyAppWidgetEntryView: View {
var entry: Provider.Entry
let moc = PersistenceController.shared.container.viewContext
let predicate = NSPredicate(format: "favorite == true")
let request = NSFetchRequest<Project>(entityName: "Project")
var body: some View {
// let result = try moc.fetch(request)
VStack {
Image("icon")
.resizable()
.aspectRatio(contentMode: .fit)
Text("Item Count: \(itemsCount)")
.padding(.bottom)
.foregroundColor(.secondary)
}
}
var itemsCount: Int {
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Project")
do {
return try PersistenceController.shared.container.viewContext.count(for: request)
} catch {
print(error.localizedDescription)
return 0
}
}
}
@main
struct MyAppWidget: Widget {
let kind: String = "MyAppWidget"
var body: some WidgetConfiguration {
StaticConfiguration(kind: kind, provider: Provider()) { entry in
MyAppWidgetEntryView(entry: entry)
}
.configurationDisplayName("MyApp Widget")
.description("Track your project count")
.supportedFamilies([.systemSmall])
}
}
但同样，我真正想做的是从实体访问属性bodyText 或image1，就像我的主应用程序如何访问它一样。例如，
VStack {
Image(uiImage: UIImage(data: project.image1 ?? self.projectImage1)!)
.resizable()
.aspectRatio(contentMode: .fill)
Text("\(project.bodyText!)")
}
这是 Widget.swift 代码，它似乎更接近我想要完成的工作，但它在获取 project.bodyText 时失败，错误为 Value of type 'FetchedResults<Project>' has no member 'bodyText' - 我无法弄清楚为什么它没有看到我的实体项目
// MARK: Core Data
var managedObjectContext: NSManagedObjectContext {
return persistentContainer.viewContext
}
var workingContext: NSManagedObjectContext {
let context = NSManagedObjectContext(concurrencyType: .privateQueueConcurrencyType)
context.parent = managedObjectContext
return context
}
var persistentContainer: NSPersistentCloudKitContainer = {
let container = NSPersistentCloudKitContainer(name: "MyAppApp")
let storeURL = URL.storeURL(for: "group.com.me.MyAppapp", databaseName: "MyAppApp")
let description = NSPersistentStoreDescription(url: storeURL)
container.loadPersistentStores(completionHandler: { storeDescription, error in
if let error = error as NSError? {
print(error)
}
})
container.viewContext.automaticallyMergesChangesFromParent = true
container.viewContext.mergePolicy = NSMergeByPropertyStoreTrumpMergePolicy
return container
}()
// MARK: WIDGET
struct Provider: TimelineProvider {
// CORE DATA
var moc = managedObjectContext
init(context : NSManagedObjectContext) {
self.moc = context
}
// WIDGET
func placeholder(in context: Context) -> SimpleEntry {
SimpleEntry(date: Date())
}
func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
let entry = SimpleEntry(date: Date())
completion(entry)
}
func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
var entries: [SimpleEntry] = []
// Generate a timeline consisting of five entries an hour apart, starting from the current date.
let currentDate = Date()
for hourOffset in 0 ..< 5 {
let entryDate = Calendar.current.date(byAdding: .hour, value: hourOffset, to: currentDate)!
let entry = SimpleEntry(date: entryDate)
entries.append(entry)
}
let timeline = Timeline(entries: entries, policy: .atEnd)
completion(timeline)
}
}
struct SimpleEntry: TimelineEntry {
let date: Date
}
struct MyAppWidgetEntryView : View {
var entry: Provider.Entry
@FetchRequest(entity: Project.entity(), sortDescriptors: []) var project: FetchedResults<Project>
var body: some View {
Text("\(project.bodyText)"). <--------------------- ERROR HAPPENS HERE
}
}
@main
struct MyAppWidget: Widget {
let kind: String = "MyAppWidget"
var body: some WidgetConfiguration {
StaticConfiguration(kind: kind, provider: Provider(context: managedObjectContext)) { entry in
MyAppWidgetEntryView(entry: entry)
.environment(\.managedObjectContext, managedObjectContext)
}
.configurationDisplayName("My Widget")
.description("This is an example widget.")
}
}
struct MyAppWidget_Previews: PreviewProvider {
static var previews: some View {
MyAppWidgetEntryView(entry: SimpleEntry(date: Date()))
.previewContext(WidgetPreviewContext(family: .systemSmall))
}
}
我接近了吗？你有没有碰巧得到类似的工作？非常感谢！
【问题讨论】：
标签： ios swift core-data swiftui widgetkit