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实现快速启动的基线配置文件

预编译热点路径，让启动过程更流畅

实现快速启动的基线配置文件 是 CoddyKit 上的免费 Jetpack Compose 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 Jetpack Compose Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Jetpack Compose 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 Startup Feels Slow

Fresh app code runs interpreted at first, then compiles in the background. Those early frames are the slowest, and users feel them as a sluggish launch.

What a Baseline Profile Is

A baseline profile lists the hot code paths your app runs at startup. Android precompiles them at install time, so they are fast from the first tap.

The Payoff: Faster Frames

With a profile shipped, startup and the first scrolls run ahead-of-time compiled. Real apps often see launch times improve by twenty to thirty percent.

How It Gets Generated

You do not write the list by hand. A Macrobenchmark test exercises your key flows, and the tooling records which methods and classes were used.

Add the Baseline Profile Plugin

Generation is driven by the baselineProfile Gradle plugin and a companion module. It runs your benchmark and writes the profile into your app.

plugins {
    id("androidx.baselineprofile")
}

Write a Collection Test

In the test you call collect and drive a critical journey, like launching and scrolling the home list, so the right paths are captured.

baselineProfileRule.collect(
    packageName = "com.app"
) { startActivityAndWait() }

Where the Profile Lives

The generated file lands in src/main/baseline-prof.txt. It ships inside your app bundle and Android applies it during install.

Profiles Are Versioned

Your code changes, so regenerate the profile when hot paths shift. A stale profile still helps, but a fresh one captures your latest startup flow.

Quick Check

A teammate asks how baseline profiles speed up launch. What is the core mechanism?

Verify the Win

Re-run your Macrobenchmark with the profile applied and compare startup timings. Numbers, not guesses, prove the improvement is real.

Startup Profiles Too

You can also mark the most launch-critical paths as a startup profile. Android prioritizes compiling those first for the snappiest possible cold start.

It Just Ships, No Setup

Best of all, users do nothing. The profile is applied automatically during install, so the speed boost arrives the first time they open your app.

Recap: Compile the Hot Paths

You generated a baseline profile from a benchmark, shipped it in your bundle, and measured a faster, smoother launch.

常见问题解答

「实现快速启动的基线配置文件」课时是免费的吗？

是的 — 「实现快速启动的基线配置文件」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 Jetpack Compose Academy 课程的其余内容，请升级到 CoddyKit PRO。 Jetpack Compose Academy 课程共包含 4 节课。

「实现快速启动的基线配置文件」这节课中我会学到什么？

预编译热点路径，让启动过程更流畅你通过在浏览器中直接运行的动手代码来练习 Jetpack Compose 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 Jetpack Compose Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Jetpack Compose 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。

「实现快速启动的基线配置文件」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 Jetpack Compose Academy 课中编写并运行代码吗？

能。每节 Jetpack Compose 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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