问题描述
使用flutter doctor检查开发环境，出现以下问题
wangyangyangdeMacBook-Pro:~ wangyang$ flutter doctor Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel stable, 2.2.1, on Mac OS X 10.15.7 19H2 darwin-x64, locale zh-Hans-US) [!] Android toolchain - develop for Android devices (Android SDK version 30.0.3) X cmdline-tools component is missing Run `path/to/sdkmanager --install "cmdline-tools;latest"` See https://developer.android.com/studio/command-line for more details. ✗ Android license status unknown. Run `flutter doctor --android-licenses` to accept the SDK licenses. See https://flutter.dev/docs/get-started/install/macos#android-setup for more details. [✓] Xcode - develop for iOS and macOS [✓] Chrome - develop for the web [✓] Android Studio (version 4.2) [✓] VS Code (version 1.61.0) [✓] Connected device (2 available) ! Doctor found issues in 1 category.
根据错误提示运行flutter doctor --android-licenses，出现以下Java异常。
wangyangyangdeMacBook-Pro:~ wangyang$ flutter doctor --android-licenses Exception in thread "main" java.lang.NoClassDefFoundError: javax/xml/bind/annotation/XmlSchema at com.android.repository.api.SchemaModule$SchemaModuleVersion.<init>(SchemaModule.java:156) at com.android.repository.api.SchemaModule.<init>(SchemaModule.java:75) at com.android.sdklib.repository.AndroidSdkHandler.<clinit>(AndroidSdkHandler.java:81) at com.android.sdklib.tool.sdkmanager.SdkManagerCli.main(SdkManagerCli.java:73) at com.android.sdklib.tool.sdkmanager.SdkManagerCli.main(SdkManagerCli.java:48) Caused by: java.lang.ClassNotFoundException: javax.xml.bind.annotation.XmlSchema at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:581) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) ... 5 more
虽然这个错误不影响在Android上的编译和运行，但是本人是个强迫症，必须消灭掉！！！
解决方案
根据上面的错误显示，猜测难道是Android SDK的问题？
打开Android Studio, Preferences-Appearance & Behavior- System Settings- Android SDK-SDK Tools
发现SDK的命令行工具没有安装。
勾选，然后选择Apply，会出现安装提示.
点击OK，会出现安装进度。
安装完成后，再次运行flutter doctor，已经没有错误了。OK 完美！
wangyangyangdeMacBook-Pro:~ wangyang$ flutter doctor Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel stable, 2.2.1, on Mac OS X 10.15.7 19H2 darwin-x64, locale zh-Hans-US) [✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3) [✓] Xcode - develop for iOS and macOS [✓] Chrome - develop for the web [✓] Android Studio (version 4.2) [✓] VS Code (version 1.61.0) [✓] Connected device (2 available) • No issues found!
