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Flutter android build issue post flutter update

build and run works fine but in release build, I started finding issue:

ERROR: Missing classes detected while running R8. Please add the missing classes or apply additional keep rules that are generated in /Users/chiragjuneja/Documents/work/playground/yashutales/badminton_score_tracker/build/flutter_inappwebview_android/outputs/mapping/release/missing_rules.txt.
ERROR: R8: Missing class android.window.BackEvent (referenced from: void io.flutter.embedding.android.FlutterActivity.startBackGesture(android.window.BackEvent) and 3 other contexts)

Solved:

After some more googling and trying out various suggestions, this worked for me.

buildTypes {
        release { 
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

updating the gradle file with the above change post adding

-keep class android.window.BackEvent { *; }

in proguard-rules.pro that I created for this only.

And I changed plugin details
from

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
}

to

plugins {
    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
    id "com.android.application" version "7.3.0" apply false
    id "org.jetbrains.kotlin.android" version "1.8.22" apply false
}

Hope it helps someone else too.

Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    After some more googling and trying out various suggestions, this worked for me.

    buildTypes {
        release { 
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    updating the gradle file with the above change post adding

    -keep class android.window.BackEvent { *; }

    in proguard-rules.pro that I created for this only.

    And I changed plugin details from

    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
}

    to

    plugins {
    id "dev.flutter.flutter-plugin-loader" version "1.0.0"
    id "com.android.application" version "7.3.0" apply false
    id "org.jetbrains.kotlin.android" version "1.8.22" apply false
}

    Hope it helps someone else too.


  2. 0

    The missing classes are related to Android and could be due to R8 shrinking essential code. To address this:

    Navigate to your Flutter project’s android directory and open the proguard-rules.pro file.
    If you don’t have this file, create one under android/app directory

    -keep class android.window.BackEvent { *; }
-keep class io.flutter.embedding.android.FlutterActivity { *; }

    Run flutter pub upgrade to update all Flutter dependencies.

    Ensure your flutter_inappwebview plugin is up to date. You can do this by checking the latest version of flutter_inappwebview and updating your pubspec.yaml

    flutter clean
flutter pub get
flutter build apk --release
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