[Android] BuildConfig is defined multiple times

[EvgenFree45]

I do not know if this is a bug or my mistake, however, after updating the plugin to version 1.3.1 (from 1.2.4), I get an error in the console that interrupts my build.

Type com.learntoflutter.flutter_embed_unity_android.BuildConfig is defined multiple times.

This error refers to two files, one of which is located at

<path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\f6262a68685fb9a64d06ca1ca87ae2a1\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex

and second

<path_to_project>\build\flutter_embed_unity_6000_0_android.transforms\1f493b52a7d095f3ee2da881e422f41b\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex

Full error text:

ERROR: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\f6262a68685fb9a64d06ca1ca87ae2a1\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex: D8: Type com.learntoflutter.flutter_embed_unity_android.BuildConfig is defined multiple times: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\f6262a68685fb9a64d06ca1ca87ae2a1\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex, <path_to_project>\build\flutter_embed_unity_6000_0_android.transforms\1f493b52a7d095f3ee2da881e422f41b\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
Type com.learntoflutter.flutter_embed_unity_android.BuildConfig is defined multiple times: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\f6262a68685fb9a64d06ca1ca87ae2a1\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex, <path_to_project>\build\flutter_embed_unity_6000_0_android.transforms\1f493b52a7d095f3ee2da881e422f41b\transformed\debug\com\learntoflutter\flutter_embed_unity_android\BuildConfig.dex

Additional information:

pubspec.yaml:
flutter_embed_unity: ^1.3.1
flutter_embed_unity_6000_0_android: ^1.2.2

Unity 6000.0.32f1
Minimum API Level Android 10.0 (API level 29)
Target API Level Android 14.0 (API level 34)

settings.gradle:

plugins {
    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
    id "com.android.application" version "8.1.0" apply false
    id "org.jetbrains.kotlin.android" version "1.8.22" apply false
}

gradle-wrapper-properties:
distributionUrl=https://services.gradle.org/distributions/gradle-8.3-bin.zip

build.gradle:

android {
    ...
    compileSdk = 35
    ndkVersion = "27.2.12479018"
   ...

[timbotimbo]

Looks like you switched from 2022_3 to 6000_0 on Android and gradle is somehow trying to merge files from both versions.

That should just be some intermediate or cache files and not an issue with the plugin.

Try to:

• run flutter clean
• delete the android/unityLibrary folder and export again from Unity.

If that doesn't help, maybe delete the android/.gradle folder and try again.

[EvgenFree45]

• flutter clean
• delete the android/unityLibrary folder and export again from Unity
• delete the android/.gradle
• flutter pub get
• restart VSCode
• build

Same error. And before this error

Note: <path_to_project>\android\unityLibrary\src\main\java\com\unity3d\player\UnityPlayerActivity.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.

In fact, I started all this because of a error with sending messages. I saw that it was fixed and decided to upgrade. Now I'm starting to lose hope that I'll be able to build the project without completely rebuilding it.

[timbotimbo]

I did some testing, but I haven't found a solution yet.

At first I was able to build both the 2022_3 and 6000_0 examples on android.
I just ran flutter build apk --release and both projects worked without any issues.

After that I tried to reproduce your issue by deliberately switching back and forth between plugin versions and cleaning caches.

I ended up with a fairly similar error, which I managed to turn into several others.

ERROR: C:\Users<user>\Documents\flutter_embed_unity\flutter_embed_unity_2022_3_android\example\build\flutter_embed_unity_2022_3_android\intermediates\rune_library_classes_jar\release\bundleLibRuneToJarRelease\classes.jar: R8: Type com.learntoflutter.flutter_embed_unity_android.constants.FlutterEmbedConstants is defined multiple times: C:\Users<user>\Documents\flutter_embed_unity\flutter_embed_unity_2022_3_android\example\build\flutter_embed_unity_2022_3_android\intermediates\rune_library_classes_jar\release\bundleLibRuneToJarRelease\classes.jar:com/learntoflutter/flutter_embed_unity_android/constants/FlutterEmbedConstants.class, C:\Users<user>\Documents\flutter_embed_unity\flutter_embed_unity_2022_3_android\example\build\flutter_embed_unity_6000_0_android\intermediates\rune_library_classes_jar\release\bundleLibRuneToJarRelease\classes.jar:com/learntoflutter/flutter_embed_unity_android/constants/FlutterEmbedConstants.class

FAILURE: Build failed with an exception.

• What went wrong:
  Execution failed for task ':app:minifyReleaseWithR8'.
  A failure occurred while executing com.android.build.gradle.internal.tasks.R8Task$R8Runnable
  Compilation failed to complete, origin: C:\Users<user>\Documents\flutter_embed_unity\flutter_embed_unity_2022_3_android\example\build\flutter_embed_unity_2022_3_android\intermediates\rune_library_classes_jar\release\bundleLibRuneToJarRelease\classes.jar:com/learntoflutter/flutter_embed_unity_android/constants/FlutterEmbedConstants.class

Just some of the variations:

Type com.learntoflutter.flutter_embed_unity_android.FlutterEmbedUnityAndroidPlugin is defined multiple times
Type com.learntoflutter.flutter_embed_unity_android.constants.FlutterEmbedConstants$Companion is defined multiple times
Type com.learntoflutter.flutter_embed_unity_android.constants.FlutterEmbedConstants is defined multiple times

Not your exact error, but probably the same issue.

Now my personal end result is:

• the 2022_3_android example project is broken on this pc, regardless of flutter clean or deleting local or global gradle caches.
  Only changing the pubspec.yaml of the plugin gets it to work.
• the 6000_0_android example project works just fine.

So I somewhat reproduced your error, but for the wrong Unity version.
I do agree that something is messed up here, even though it all worked fine for me a couple of hours ago.

I'll need to see if I can reproduce this on another machine later.

Temp workaround

For a possible quick workaround.

You could download the plugin to a local folder, and import it in your pubspec.yaml using a local path.

  flutter_embed_unity:
   path: ../../flutter_embed_unity # add your relative path here

Then in the pubspec.yaml of that local project make sure only 6000_0_android is used.

dependencies:
  flutter:
    sdk: flutter
  flutter_embed_unity_platform_interface: ^1.0.1
  # flutter_embed_unity_2022_3_android: ^1.1.4 # disable this one with a comment
  flutter_embed_unity_6000_0_android: ^1.2.2
  flutter_embed_unity_2022_3_ios: ^1.0.2

dev_dependencies:
  flutter_lints: ^2.0.3

flutter:
  plugin:
    platforms:
      android:
        default_package: flutter_embed_unity_6000_0_android #flutter_embed_unity_2022_3_android  # change this one to 6000_0
      ios:
        default_package: flutter_embed_unity_2022_3_ios

You could also do the opposite for 2022_3_android instead by removing any reference to 6000_0.

[EvgenFree45]

I've completely rebuilt the project. I created a clean project and moved everything to it piece by piece from my work project, except flutter_embed. Then I made a backup and added flutter_embed there, after which I performed the rest of the configuration in accordance with the manual.

• Added lines to pubspec.yaml
• Added all the lines to the gradle files
• Edited the MainActivity
• The Unity project was already set up, so I just exported
• Then I tried to build the project in debugging mode and got a similar error.

ERROR: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\b61a51d04aeb4575e41bf22ce940df4c\transformed\debug\com\learntoflutter\flutter_embed_unity_android\FlutterEmbedUnityAndroidPlugin.dex: D8: Type com.learntoflutter.flutter_embed_unity_android.FlutterEmbedUnityAndroidPlugin is defined multiple times: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\b61a51d04aeb4575e41bf22ce940df4c\transformed\debug\com\learntoflutter\flutter_embed_unity_android\FlutterEmbedUnityAndroidPlugin.dex, <path_to_project>\build\flutter_embed_unity_6000_0_android.transforms\35405aaa2ac011ec0d6dc133d08037cb\transformed\debug\com\learntoflutter\flutter_embed_unity_android\FlutterEmbedUnityAndroidPlugin.dex
ERROR: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\b61a51d04aeb4575e41bf22ce940df4c\transformed\debug\com\learntoflutter\flutter_embed_unity_android\unity\FakeUnityPlayerActivity.dex: D8: Type com.learntoflutter.flutter_embed_unity_android.unity.FakeUnityPlayerActivity is defined multiple times: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\b61a51d04aeb4575e41bf22ce940df4c\transformed\debug\com\learntoflutter\flutter_embed_unity_android\unity\FakeUnityPlayerActivity.dex, <path_to_project>\build\flutter_embed_unity_6000_0_android.transforms\35405aaa2ac011ec0d6dc133d08037cb\transformed\debug\com\learntoflutter\flutter_embed_unity_android\unity\FakeUnityPlayerActivity.dex
com.android.builder.dexing.DexArchiveMergerException: Error while merging dex archives:
Learn how to resolve the issue at https://developer.android.com/studio/build/dependencies#duplicate_classes.
Type com.learntoflutter.flutter_embed_unity_android.FlutterEmbedUnityAndroidPlugin is defined multiple times: <path_to_project>\build\flutter_embed_unity_2022_3_android.transforms\b61a51d04aeb4575e41bf22ce940df4c\transformed\debug\com\learntoflutter\flutter_embed_unity_android\FlutterEmbedUnityAndroidPlugin.dex, <path_to_project>\build\flutter_embed_unity_6000_0_android.transforms\35405aaa2ac011ec0d6dc133d08037cb\transformed\debug\com\learntoflutter\flutter_embed_unity_android\FlutterEmbedUnityAndroidPlugin.dex

I also tried to build the project in release mode and got a similar error again, but with a different class name.

ERROR: <path_to_project>\build\flutter_embed_unity_2022_3_android\intermediates\runtime_library_classes_jar\release\classes.jar: R8: Type com.learntoflutter.flutter_embed_unity_android.constants.FlutterEmbedConstants$Companion is defined multiple times: <path_to_project>\build\flutter_embed_unity_2022_3_android\intermediates\runtime_library_classes_jar\release\classes.jar:com/learntoflutter/flutter_embed_unity_android/constants/FlutterEmbedConstants$Companion.class, <path_to_project>\build\flutter_embed_unity_6000_0_android\intermediates\runtime_library_classes_jar\release\classes.jar:com/learntoflutter/flutter_embed_unity_android/constants/FlutterEmbedConstants$Companion.class

I used the solution you suggested for a quick fix and it worked! Thank you so much for your time, I hope there will be an official fix soon.

[jamesncl]

I'm struggling to reproduce this, @timbotimbo what steps did you take? I'm playing around with the example android project, adding and removing flutter_embed_unity_6000_0_android from the pubspec.yaml and switching between versions of flutter_embed_unity but haven't seen these errors yet. When you say you are 'cleaning caches', which caches?

Looking at the workaround, given that using a new local copy of flutter_embed_unity seems to fix the problem, I'm wondering if the solution is to repair / reset the copy of flutter_embed_unity in pub's cache. So perhaps the following might solve the problem:

Perform a clean reinstallation of all packages in your system cache:

dart pub cache repair

Or empty the entire system cache:

dart pub cache clean

Either of these commands will result in having to re-download all pub packages again. To avoid this you may be able to just manually delete the flutter_embed_unity packages from the cache folder (on Mac this is for example /Users/james/.pub-cache/hosted/pub.dev)

See https://dart.dev/tools/pub/cmd/pub-cache