启动Flutter应用时遇Could not GET jitpack.io资源错误求助

问题核心 #

构建Flutter应用时，Gradle无法获取https://jitpack.io/me/carda/androidcore/0.7.2/androidcore-0.7.2.aar，服务器返回521状态码。这是Jitpack服务器端的连接故障（Cloudflare 521错误表示源服务器拒绝了Cloudflare的连接请求），和你的本地环境无关（此前代码运行正常也验证了这一点）。

解决方案 #

• 等待服务器恢复：521属于服务端临时故障，暂停构建10-30分钟后，重新执行flutter run。
• 清理Gradle缓存：
  1. 执行命令：flutter clean
  2. 手动删除项目根目录下android/.gradle文件夹，再重新构建。
• 更换依赖版本：如果该版本长期无法访问，去对应库的代码仓库查看可用版本，修改项目中的依赖配置（pubspec.yaml或Android模块的build.gradle），替换为其他稳定版本。
• 本地导入依赖：若上述方法无效，可尝试将该aar文件从其他可信源下载后作为本地依赖导入：
  1. 将androidcore-0.7.2.aar放到android/app/libs目录
  2. 在android/app/build.gradle的dependencies块中添加：

     implementation files('libs/androidcore-0.7.2.aar')
     

  3. 移除原来指向Jitpack的远程依赖。

补充说明 #

你提供的flutter doctor结果中，Visual Studio的缺失组件仅影响Windows平台开发，和当前Android构建失败无关，无需优先处理。

原错误日志 #

Launching lib\main.dart on SM A125F in debug mode...
Running Gradle task 'assembleDebug'...
Warning: This version only understands SDK XML versions up to 2 but an SDK XML file of version 3 was encountered. This can happen if you use versions of Android Studio and the command-line tools that were released at different times.
Warning: élément inattendu (URI : "", local : "extension-level"). Les éléments attendus sont <{}codename>,<{}layoutlib>,<{}api-level>
Warning: élément inattendu (URI : "", local : "base-extension"). Les éléments attendus sont <{}codename>,<{}layoutlib>,<{}api-level>
Format incorrect du paramètre -

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':app:mergeDebugAssets'.

Could not resolve all files for configuration ':app:debugRuntimeClasspath'.
Failed to transform androidcore-0.7.2.aar (me.carda:androidcore:0.7.2) to match attributes {artifactType=android-assets, org.gradle.category=library, org.gradle.dependency.bundling=external, org.gradle.libraryelements=aar, org.gradle.status=release, org.gradle.usage=java-runtime}.
Could not download androidcore-0.7.2.aar (me.carda:androidcore:0.7.2)
Could not get resource 'https://jitpack.io/me/carda/androidcore/0.7.2/androidcore-0.7.2.aar'.
Could not GET 'https://jitpack.io/me/carda/androidcore/0.7.2/androidcore-0.7.2.aar'. Received status code 521 from server:

• Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

• Get more help at https://help.gradle.org

BUILD FAILED in 1m 8s
Retrying Gradle Build: #1, wait time: 100ms
[!] Gradle threw an error while downloading artifacts from the network.

本地环境检测结果 #

Doctor summary (to see all details, run flutter doctor -v):
[√] Flutter (Channel stable, 3.3.3, on Microsoft Windows [version 10.0.22621.963], locale fr-SN)
Checking Android licenses is taking an unexpectedly long time...[√] Android toolchain - develop for Android devices (Android SDK version 33.0.0)
[√] Chrome - develop for the web
[!] Visual Studio - develop for Windows (Visual Studio Community 2022 17.2.6)
    X Visual Studio is missing necessary components. Please re-run the Visual Studio installer for the "Desktop development with C++" workload, and include these components:
        MSVC v142 - VS 2019 C++ x64/x86 build tools
         - If there are multiple build tool versions available, install the latest
        C++ CMake tools for Windows
        Windows 10 SDK
[√] Android Studio (version 2021.3)
[√] IntelliJ IDEA Ultimate Edition (version 2022.1)
[√] VS Code (version 1.74.1)
[√] Connected device (4 available)
[√] HTTP Host Availability

! Doctor found issues in 1 category.

内容的提问来源于stack exchange，提问作者Saliou Seck