How to intergrate Tensorflow to Android native plugin

Questions & Answers
1

I know Unity has release TensorFlowSharp. But is it possible to intergrate Tensorflow android to Android plugin. I have import to gradle of Android plugin:

implementation "org.tensorflow:tensorflow-android:1.8.0"

also copy tensorflow aar to plugin folder of Unity project. But i am stuck in building Unity app in Android.
Error:

com.android.build.api.transform.TransformException: java.lang.RuntimeException: java.lang.RuntimeException: Unable to pre-dex
CommandInvokationFailure: Gradle build failed. 
/Library/Java/JavaVirtualMachines/jdk1.8.0_162.jdk/Contents/Home/bin/java -classpath "/Applications/Unity/PlaybackEngines/AndroidPlayer/Tools/gradle/lib/gradle-launcher-4.0.1.jar" org.gradle.launcher.GradleMain "-Dorg.gradle.jvmargs=-Xmx2048m" "assembleRelease"

stderr[
Dex: Error converting bytecode to dex:
Cause: Dex cannot parse version 52 byte code.
This is caused by library dependencies that have been compiled using Java 8 or above.
If you are using the 'java' gradle plugin in a library submodule add 
targetCompatibility = '1.7'
sourceCompatibility = '1.7'
2

In case anyone has this problem in the future, these steps worked for me:

  1. Download the tensorflow lite aar at https://mvnrepository.com/artifact/org.tensorflow/tensorflow-lite/1.13.1
  2. Create a “libs” folder in your plugin’s root directory and add the downloaded AAR there
  3. In your plugin’s gradle file add compileOnly files('libs/tensorflow-lite-1.13.1.aar')
  4. Add the AAR to your Unity project in Assets/Plugins/Android

compileOnly makes it so that gradle doesn’t include the AAR in your plugin, but can still access it at runtime if you have added it to your Unity project’s plugins directory.