SwiftUI Academy · 课时

使用 ForEach 循环

根据数据数组渲染各行。

使用 ForEach 循环 是 CoddyKit 上的免费 SwiftUI Academy 课时。这是第 2 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。

Why ForEach

Hardcoding rows works for two items, but real data lives in arrays. ForEach builds one row per element automatically. 🔁

let fruits = ["Apple", "Pear", "Kiwi"]

ForEach Inside List

Drop a ForEach inside a List and it generates one row for every item in your collection, no matter how many there are.

List {
    ForEach(fruits, id: \.self) { fruit in
        Text(fruit)
    }
}

The Closure Gives You Each Item

The closure runs once per element, handing you that item so you can build its row from real data.

ForEach(fruits, id: \.self) { fruit in
    Text(fruit)
}

Identity Matters

SwiftUI needs to tell rows apart, so ForEach always wants a way to identify each element uniquely.

The id Parameter

For simple value arrays, pass id set to a key path like .self so each value can identify itself uniquely to SwiftUI.

ForEach(scores, id: \.self) { score in
    Text("\(score)")
}

Looping a Range

Need a fixed count instead of an array? Pass a range and ForEach hands you each index in turn, perfect for placeholder rows.

ForEach(0..<5) { index in
    Text("Row \(index)")
}

Building Rich Rows

Inside the closure you can return any view, so each ForEach row can be a full HStack with icons and labels.

ForEach(fruits, id: \.self) { fruit in
    HStack {
        Image(systemName: "leaf")
        Text(fruit)
    }
}

Mixing Static and Dynamic

A List can hold a static header Text and a ForEach loop together, blending fixed and data-driven rows.

List {
    Text("Fruits")
    ForEach(fruits, id: \.self) { Text($0) }
}

Looping Structs

When you loop an array of structs, each item carries multiple fields you can show across the row.

ForEach(people, id: \.name) { person in
    Text(person.name)
}

Data Drives the UI

Change the array and the rows follow right along. With ForEach, your list is simply a live mirror of whatever data you give it.

Beyond Lists

ForEach is not just for lists. It also fills VStack, HStack, and grids with repeated views from any collection.

VStack {
    ForEach(fruits, id: \.self) { Text($0) }
}

Quick Check

Recall what the ForEach closure receives.

Recap

You learned ForEach: it turns any collection into rows, handing you each item so your UI tracks your data automatically. 🎉

常见问题解答

「使用 ForEach 循环」课时是免费的吗？

是的 — 「使用 ForEach 循环」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。

「使用 ForEach 循环」这节课中我会学到什么？

根据数据数组渲染各行。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 2 节课，共 4 节。

「使用 ForEach 循环」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。

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