Web アプリをホット リロードすると、このエラーが発生します。
これはflutter doctor -v出力です：
[√] Flutter (Channel dev, v1.10.14, on Microsoft Windows [Version 6.1.7601], locale en-US)
• Flutter version 1.10.14 at F:\flutter
• Framework revision 1946fc4 (2 weeks ago), 2019-10-07 15:23:31 -0700
• Engine revision 1d62160fdb
• Dart version 2.6.0 (build 2.6.0-dev.5.0 d6c6d12ebf)
[X] Android toolchain - develop for Android devices
X Unable to locate Android SDK.
Install Android Studio from: https://developer.android.com/studio/index.html
On first launch it will assist you in installing the Android SDK components.
(or visit https://flutter.dev/setup/#android-setup for detailed instructions).
If the Android SDK has been installed to a custom location, set ANDROID_HOME to that location.
You may also want to add it to your PATH environment variable.
[√] Chrome - develop for the web
• Chrome at C:\Program Files (x86)\Google\Chrome\Application\chrome.exe
[√] Android Studio (version 3.5)
• Android Studio at F:\AndroidStudio
• Flutter plugin version 40.2.2
• Dart plugin version 191.8423
• Java version OpenJDK Runtime Environment (build 1.8.0_202-release-1483-b03)
[√] Connected device (2 available)
• Chrome • chrome • web-javascript • Google Chrome 77.0.3865.120
• Headless Server • headless-server • web-javascript • Flutter Tools
! Doctor found issues in 1 category.