出现这样的错误是怎么回事

Doctor summary (to see all details, run flutter doctor -v):

[√] Flutter (Channel stable, v1.12.13+hotfix.8, on Microsoft Windows [Version 10.0.18363.720], locale zh-CN)

[!] Android toolchain - develop for Android devices (Android SDK version 29.0.3)

    X Android license status unknown.

      Try re-installing or updating your Android SDK Manager.

      See https://developer.android.com/studio/#downloads or visit https://flutter.dev/setup/#android-setup for detailed

      instructions.

[√] Android Studio (version 3.6)

[!] VS Code (version 1.43.2)

    X Flutter extension not installed; install from

      https://marketplace.visualstudio.com/items?itemName=Dart-Code.flutter

[!] Connected device

    ! No devices available