Apple Scrumdinger示例应用程序使用两个真实数据源来展示不同的数据更新方式。本地数据源存储在设备上，通常是持久的，而云数据源存储在远程服务器上。

以下是示例代码中使用两个数据源的方式：

class ScrumsData: ObservableObject { @Published var scrums: [DailyScrum]

init(scrums: [DailyScrum] = []) {
    self.scrums = scrums
    #if DEBUG
    createSampleData()
    #endif
}

func load() {
    // Load the local data stored on the device
    scrums = [
        DailyScrum(title: "Design", attendees: [attendees[0], attendees[1]], lengthInMinutes: 60),
        DailyScrum(title: "App Dev", attendees: attendees, lengthInMinutes: 30),
        DailyScrum(title: "Web Dev", attendees: attendees, lengthInMinutes: 90)
    ]
}

func save(_ scrum: DailyScrum) {
    // Save the edits to the local data
}

}

class DataController: ObservableObject { static let shared = DataController()

@Published var hasLoaded = false
let scrumsData = ScrumsData()
var deletions: [DailyScrum] = []

init() {
    #if DEBUG
    scrumsData.createSampleData()
    #endif
    scrumsData.load()
    hasLoaded = true
}

func delete(_ scrum: DailyScrum) {
    deletions.append(scrum)
    scrumsData.scrums.removeAll(where: {$0.id == scrum.id})
}

}

在这个示例中，ScrumsData类是本地数据源，DataController类是云数据源。ScrumsData类用于加载和保存本地数据，而DataController类用于在远程服务器上执行相同的操作。然而，这两个数据源都使用@Published属性来通知视图层刷新。

使用多个数据源可以提