Google-signin: Android: Execution failed for task ':app:transformClassesWithDexForDebug'.

[goodhyun]

I know this is related to the build.gradle, but still don't know how to solve it.

Currently, 0.9.0 with 0.42, I haven't had a problem with a previous setup.

Dex: Error converting bytecode to dex:
Cause: com.android.dex.DexException: Multiple dex files define Lcom/google/android/gms/internal/zzmy;
    UNEXPECTED TOP-LEVEL EXCEPTION:
    com.android.dex.DexException: Multiple dex files define Lcom/google/android/gms/internal/zzmy;
        at com.android.dx.merge.DexMerger.readSortableTypes(DexMerger.java:579)
        at com.android.dx.merge.DexMerger.getSortedTypes(DexMerger.java:535)
        at com.android.dx.merge.DexMerger.mergeClassDefs(DexMerger.java:517)
        at com.android.dx.merge.DexMerger.mergeDexes(DexMerger.java:164)
        at com.android.dx.merge.DexMerger.merge(DexMerger.java:188)
        at com.android.dx.command.dexer.Main.mergeLibraryDexBuffers(Main.java:504)
        at com.android.dx.command.dexer.Main.runMonoDex(Main.java:334)
        at com.android.dx.command.dexer.Main.run(Main.java:277)
        at com.android.dx.command.dexer.Main.main(Main.java:245)
        at com.android.dx.command.Main.main(Main.java:106)

:app:transformClassesWithDexForDebug FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':app:transformClassesWithDexForDebug'.
> com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: java.lang.UnsupportedOperationException

[goodhyun]

Oh well, this is how I solved it eventually.

:+ and commenting out.

  compile 'com.google.android.gms:play-services-auth:+' // should be at least 9.0.0
    compile (project(":react-native-google-signin")){         
        exclude group: "com.google.android.gms" // very important
    }
}

// apply plugin: 'com.google.gms.google-services' // <--- this should be the last line

[chrisharrison]

Just to make @goodhyun's helpful answer more clear. The last line (applying the 'com.google.gms.google-services' plugin) should indeed be commented out.

This confused us at first because it says:

this should be the last line

We were confused as to why a commented-out line should have to be in a particular place.

[Rioland]

Error:Execution failed for task ':app:transformClassesWithDexForDebug'.

com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.dex.DexException: Multiple dex files define Lcom/google/android/gms/auth/api/signin/internal/zzf;