SwiftUI Academy · 课时

下拉刷新

使用 refreshable 修饰符重新加载数据。

下拉刷新 是 CoddyKit 上的免费 SwiftUI Academy 课时。这是第 4 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 SwiftUI Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 SwiftUI Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Refreshing on Demand

Users expect to pull a list down to reload it. SwiftUI bakes this gesture in with a single modifier, no gesture code required. ✨

Meet refreshable

Attach the refreshable modifier to a List. Pulling down reveals a spinner and runs the async work you provide.

.refreshable {
    await reload()
}

It Expects Async Work

The refreshable closure is async, so it pairs perfectly with await and modern Swift concurrency for fetching data.

Spinner Tied to Your Task

The pull-to-refresh spinner stays visible until your await finishes. SwiftUI hides it the moment the work completes.

A Simple Reload

Inside refreshable, call an async function that fetches fresh data and updates your @State array on completion.

func reload() async {
    items = await fetchItems()
}

Awaiting a Network Call

A real reload usually awaits a network request. Use URLSession with async/await to pull new items from a server.

let (data, _) = try await
    URLSession.shared.data(from: url)

Update State After Await

Once the await returns, assign the decoded results to your @State array and the list refreshes with the new rows.

let fresh = try decoder.decode(
    [Item].self, from: data)
items = fresh

Handle Errors Gracefully

Network calls can fail. Wrap the work in do/catch so a dropped connection shows a message instead of crashing.

do {
    items = try await fetchItems()
} catch {
    showError = true
}

Refreshable Needs a List

The pull gesture only works on scrollable containers like List or ScrollView. Attaching refreshable to a VStack does nothing.

Keep It Quick

Refresh should feel snappy. If your fetch is slow, show progress and avoid blocking the main thread with heavy work.

Pairs With Other Editing

Pull-to-refresh sits happily beside onDelete, onMove, and add. Together they make a fully interactive, editable list. ✨

Quick Check

What kind of closure does refreshable take?

Recap: Pull-to-Refresh

You added reload-on-pull with the async refreshable modifier on a List, awaiting fresh data and handling errors. 🎉

常见问题解答

「下拉刷新」课时是免费的吗？

是的 — 「下拉刷新」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 SwiftUI Academy 课程的其余内容，请升级到 CoddyKit PRO。 SwiftUI Academy 课程共包含 4 节课。

「下拉刷新」这节课中我会学到什么？

使用 refreshable 修饰符重新加载数据。你通过在浏览器中直接运行的动手代码来练习 SwiftUI Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 SwiftUI Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 SwiftUI Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 4 节课，共 4 节。

「下拉刷新」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 SwiftUI Academy 课中编写并运行代码吗？

能。每节 SwiftUI Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

此课程中的所有课时

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