SwiftUI Academy · 课时

SwiftUI 应用文件的结构

了解 @main、App、WindowGroup 和 ContentView。

SwiftUI 应用文件的结构 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。

The App File

Every SwiftUI project has a file named after your app, like MyFirstApp.swift. This app file is the true entry point where your whole app begins. 📱

The @main Marker

The @main attribute tells Swift exactly where your program starts. iOS launches your app by running the type marked with it.

@main
struct MyFirstApp: App {
}

Conforming to App

Your main struct conforms to the App protocol. This is the SwiftUI blueprint for an application, describing what scenes it shows.

The body Property

Inside the App struct, a body property describes your app's scenes. SwiftUI reads it to know what to display when the app launches.

var body: some Scene {
    WindowGroup {
        ContentView()
    }
}

Scenes, Not Views

The app's body returns a Scene, not a View. A scene is a container for a window or screen that holds your actual views inside it.

WindowGroup

WindowGroup is the most common scene. It manages your app's main window and, on iPhone, simply fills the whole screen.

Your Root View

Inside WindowGroup you place your root view, usually ContentView(). It is the first screen the user sees when the app opens.

ContentView Lives Apart

ContentView sits in its own file, separate from the app file. Keeping the entry point and the UI apart keeps your project tidy and clear.

How It Flows

The chain is simple: @main starts the App, the App shows a WindowGroup, and the WindowGroup displays your ContentView. ✨

One @main Only

An app can have just one @main entry point. The template already provides it, so you rarely add or change this part yourself.

Where You Work

You will spend most of your time editing views like ContentView, not the app file. The app file mostly just wires everything together.

Quick Check

What is the job of the WindowGroup scene in the app file?

Recap

You learned the chain: @main on the App struct returns a WindowGroup scene that shows ContentView. That is how a SwiftUI app boots up. 🧩

常见问题解答

「SwiftUI 应用文件的结构」课时是免费的吗？

是的 — 「SwiftUI 应用文件的结构」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。

「SwiftUI 应用文件的结构」这节课中我会学到什么？

了解 @main、App、WindowGroup 和 ContentView。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。

「SwiftUI 应用文件的结构」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

← 返回 SwiftUI Academy