Gradle Android SDK integration with Unity [duplicate] - unity3d

Question

My project uses these plugins:
OneSignal
GooglePlayServices
Adjust
Google Analytics
Unity IAP
Facebook SDK
Those plugins are used in almost every project.
But I am over field references count
This is my .aar file list
What should I do to decrease reference count?

Answer 1

So What should i do to decrease reference count ?
You have so many plugins with many functions/fields. There is a limit when building this from Unity's Editor and you have reached that limit.
To decrease reference count, you have to delete some these plugins but I am sure that you need them and deletion may not be the appropriate solution in this case.
The only way to actually get around this and build for Android at this moment is to export the Project as Android Project then build it with Android Studio. This removes the reference limit imposed by Unity's Editor.
EDIT
I forgot to mention that you have to enable multidex after exporting it out. Since many people go through this problem daily, I decided to add a thorough instruction on how to fix this problem by exporting it out and also how to fix it without exporting it.
FIX BY EXPORTING THE PROJECT
1A.Export the Unity Project as Android Project.
1B.Import into Android Studio:
If you get grade error when importing into Android Studio like the one below:
Error:org.gradle.api.internal.tasks.DefaultTaskInputs$TaskInputUnionFileCollection
cannot be cast to
org.gradle.api.internal.file.collections.DefaultConfigurableFileCollection
In the "dependencies" block which is in the "buildscript" block in the build.gradle file, change:
classpath 'com.android.tools.build.gradle.2.1.0'
to
classpath 'com.android.tools.build:gradle:2.2.3'
If you export the Project and still get the-same error, you need to manually enable multidex. Below is a simplified step to follow from Google's doc that will be shown to you in the error:
2.Add android:name="android.support.multidex.MultiDexApplication" > to the
application tag in the AndroidManifest.xml file.
3.Add compile 'com.android.support:multidex:1.0.1' to the "dependencies" block in the build.gradle file.
4.Add multiDexEnabled true to the "defaultConfig" block which is in the "android" block in the build.gradle file.
Build APK and see if it works. If the reference count error is gone, stop here.
5.Getting a GC overhead exception like the one below?
java.lang.OutOfMemoryError: GC overhead limit exceeded
Increase the heap size that will be used when performing dex operation. From this solution, add the following to the "android" block in the build.gradle file:
dexOptions {
javaMaxHeapSize "4g"
}
FIX WITHOUT EXPORTING THE PROJECT
Must have Unity 5.5 and above to do this:
1.Go to <UnityInstallationDirecory>\Editor\Data\PlaybackEngines\AndroidPlayer\Tools\GradleTemplates, Copy the mainTemplate.gradle file to your <ProjectName>Assets\Plugins\Android folder.
2.Go to <UnityInstallationDirecory>\Editor\Data\PlaybackEngines\AndroidPlayer\Apk, Copy the AndroidManifest.xml file to your <ProjectName>Assets\Plugins\Android
3.Open both the mainTemplate.gradle and AndroidManifest.xml file you just copied with Visual Studio then do the modification from the FIX BY EXPORTING THE PROJECT instruction above. Skip/Ignore step #1A and #1B. Just do steps from #2 to #5. That's it.
This is what the final mainTemplate.gradle should look like and this is what the final AndroidManifest.xml should look like. This is only for reference purposes. I suggest you don't use mine but instead follow the copy steps above to create yours because future Unity versions can come with different files. You want to make sure you use the latest one or you may have problems building it.
4.Build APK and see if it works:
--
If the reference count error is gone, stop here:
5.Getting an error like the one below?
Build Failure Release builds have to be signed when using Gradle
Just sign the apk from the Publishing Settings in the Build Settings. You can create new keystore or use an existing one.
6.Another error like below?
Error: Avoid hardcoding the debug mode; leaving it out allows debug
and release builds to automatically assign one [HardcodedDebugMode]
Remove android:debuggable="true"> from the AndroidManifest.xml file.
If this non exporting solution did not work for you then you have to
use the exporting solution.

Answer 2

IMO, The accepted answer isn't correct (or only partly correct). Exporting an Android studio will not "magically" fix this issue. Also, from my experience, the exported Android studio project does not always build right away and you have to fix lots of things before you can actually build it.
You are using lots of plugins and so you faced an Android limitation of not being able to reference more than 64k methods.
There are a few things you can try to solve this:
Delete some of these plugins, if possible (as already suggested in the accepted answer).
Use multidex. In the past this was only possible by exporting the project to Android studio and building it there. Starting with Unity 5.5 you can build your project using Gradle right from Unity. This means you can create a custom gradle file that configures your game to use Multidex. This doesn't reduce the method ref count, but it works around it by splitting your native Java count into multiple dex files.
Use ProGuard - since you can use Gradle from Unity, you can also define ProGuard to run and remove any code that is not used.