[Question] please help me about build apk error

[jjjunehkim]

Question

An error occurred while attempting to create an APK file using the "flet build apk" command. The error message is below.

Previously, it was generated normally.
Since then, the Python version, flet version, and flutter version have not been updated and are in the same state.
However, when I tried to generate an APK today, an error occurred.

I don't know what is problem.
please help me..

python : 3.13
flet : 0.28.3
flutter : 3.29.0

Code sample

No response

Error message

[17:21:55] JDK installed ✅
           Android SDK installed ✅
[17:22:01] Created Flutter bootstrap project from gh:flet-dev/flet-build-template with ref "0.28.3" ✅
[17:24:34] Packaged Python app ✅
           Registered Flutter user extensions ✅
[17:24:39] Customized app icons ✅
[17:24:56] Generated app icons ✅
           Customized app splash images ✅
[17:25:05] Generated splash screens ✅
[17:26:49] Resolving dependencies...
           Downloading packages...
             archive 3.6.1 (4.0.7 available)
             audioplayers 5.2.1 (6.5.1 available)
             audioplayers_android 4.0.3 (5.2.1 available)
             audioplayers_darwin 5.0.2 (6.3.0 available)
             audioplayers_linux 3.1.0 (4.2.1 available)
             audioplayers_platform_interface 6.1.0 (7.1.1 available)
             audioplayers_web 4.1.0 (5.1.1 available)
             audioplayers_windows 3.1.0 (4.2.1 available)
             characters 1.4.0 (1.4.1 available)
             checked_yaml 2.0.3 (2.0.4 available)
             device_info_plus 11.5.0 (12.0.0 available)
             fl_chart 0.69.2 (1.1.0 available)
           ! flet 0.28.3 (overridden)
             flutter_lints 2.0.3 (6.0.0 available)
             flutter_native_splash 2.4.4 (2.4.6 available)
             image 4.3.0 (4.5.4 available)
             intl 0.19.0 (0.20.2 available)
             js 0.6.7 (0.7.2 available)
             lints 2.1.1 (6.0.0 available)
             material_color_utilities 0.11.1 (0.13.0 available)
             meta 1.16.0 (1.17.0 available)
             package_info_plus 8.3.1 (9.0.0 available)
             petitparser 6.1.0 (7.0.1 available)
             sensors_plus 4.0.2 (7.0.0 available)
             sensors_plus_platform_interface 1.2.0 (2.0.1 available)
           ! serious_python 0.9.3 from git https://github.com/flet-dev/serious-python.git at 211d3f in
           src/serious_python (overridden)
             synchronized 3.3.1 (3.4.0 available)
             toml 0.15.0 (0.16.0 available)
             url_launcher_android 6.3.20 (6.3.21 available)
             url_strategy 0.2.0 (discontinued)
             vector_math 2.1.4 (2.2.0 available)
           ! wakelock_plus 1.3.3 (overridden) (1.4.0 available)
           ! web 1.1.1 (overridden)
             web_socket_channel 2.4.5 (3.0.3 available)
           ! webview_flutter_android 4.10.2 (overridden)
             win32 5.13.0 (5.14.0 available)
           ! window_manager 0.4.3 (overridden) (0.5.1 available)
             xml 6.5.0 (6.6.1 available)
           Got dependencies!
           1 package is discontinued.
           34 packages have newer versions incompatible with dependency constraints.
           Try `flutter pub outdated` for more information.

           Running Gradle task 'assembleRelease'...
           Gradle build config:
             minSdkVersion: 21
             targetSdkVersion: 35
             versionCode: 1
             versionName: 1.0.0
           Running Gradle task 'assembleRelease'...                           94.3s

           Warning: SDK processing. This version only understands SDK XML versions up to 3 but an SDK XML file of
           version 4 was encountered. This can happen if you use versions of Android Studio and the command-line tools
           that were released at different times.
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/webview_flutte
           r_android.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android' is
           too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_ss
           l_auth_error.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android' is
           too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_we
           bview_controller.dart:1:1: Error: The language version 3.9 specified for the package
           'webview_flutter_android' is too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_we
           bview_cookie_manager.dart:1:1: Error: The language version 3.9 specified for the package
           'webview_flutter_android' is too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_we
           bview_platform.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android'
           is too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_we
           bkit.g.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android' is too
           high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_pr
           oxy.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android' is too
           high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/android_we
           bkit_constants.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android'
           is too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/platform_v
           iews_service_proxy.dart:1:1: Error: The language version 3.9 specified for the package
           'webview_flutter_android' is too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           /C:/Users/User/AppData/Local/Pub/Cache/hosted/pub.dev/webview_flutter_android-4.10.2/lib/src/weak_refer
           ence_utils.dart:1:1: Error: The language version 3.9 specified for the package 'webview_flutter_android' is
           too high. The highest supported language version is 3.7.
           // Copyright 2013 The Flutter Authors. All rights reserved.
           ^
           Target kernel_snapshot_program failed: Exception


           FAILURE: Build failed with an exception.

           * What went wrong:
           Execution failed for task ':app:compileFlutterBuildRelease'.
           > Process 'command 'C:\src\flutter\flutter\bin\flutter.bat'' finished with non-zero exit value 1

           * 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 33s
           Gradle task assembleRelease failed with exit code 1

[17:26:58] Doctor summary (to see all details, run flutter doctor -v):
           [√] Flutter (Channel stable, 3.29.0, on Microsoft Windows [Version 10.0.26100.6584], locale ko-KR)
           [√] Windows Version (11 Pro 64-bit, 24H2, 2009)
           [!] Android toolchain - develop for Android devices (Android SDK version 35.0.0)
               ! Some Android licenses not accepted. To resolve this, run: flutter doctor --android-licenses
           [√] Chrome - develop for the web
           [√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.11.2)
           [√] Android Studio (version 2024.1)
           [√] VS Code (version 1.104.0)
           [√] Connected device (3 available)
           [√] Network resources

           ! Doctor found issues in 1 category.

╭──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────╮
│ Error building Flet app - see the log of failed command above.

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• I have searched for answers to my question both in the issues and in previous discussions.

[jjjunehkim]

A solution was found and processed in isuue(#5630).
--> #5630