[移动开发]SwiftUI 快速实现CoreDate 持久化

在swiftUI开发中，CoreDate可以很方便的处理数据持久化任务，直接在swiftUI页面中就可以编辑。
在使用coredate的地方应该有的代码：

初始化：

@Environment(\.managedObjectContext) private var viewContext

@FetchRequest(entity: HabitItem.entity(), sortDescriptors: [])
var HabitItems: FetchedResults<HabitItem>
    
@FetchRequest(sortDescriptors: [NSSortDescriptor(keyPath: \Item.timestamp, ascending: true)],animation: .default)
private var items: FetchedResults<Item>

这部分内容放到stuck中声明即可。注意与容器中的名称对应。

保存新内容：

    private func addItem() {
        withAnimation {
            let newItem = Item(context: viewContext)
            newItem.timestamp = Date()

            do {
                try viewContext.save()
            } catch {
                // Replace this implementation with code to handle the error appropriately.
                // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
                let nsError = error as NSError
                fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
            }
        }
    }