64 bit version issue in react-native android app by google play store

Question

According to https://android-developers.googleblog.com/2017/12/improving-app-security-and-performance.html:

In August 2019, Play store will require that new apps and app updates with native libraries provide 64-bit versions in addition to their 32-bit versions.

I have a React Native application (which includes native code). My question is how can I know whether a third party library I'm using or even my own code is not supporting 64-bit? And how can I fix it?

Update

I added x86_64 to my build.gradle and I now see the x86_64 folder in the apk but I think some of the files are missing.

Here is, how my x86 folder looks like:

And here is how my x86_64 folder looks like:

Answer 1

React Native will support 64 bit for android starting version 0.59

https://github.com/facebook/react-native/issues/2814#issuecomment-457688789

https://github.com/facebook/react-native/commit/f3e5cce4745c0ad9a5c697be772757a03e15edc5

Answer 2

All of the native code for an app is stored in the libs/ directory in the root of the apk. eg for compiled ARM or x86 code, you can find it in libs/architecture_type/lib_name.so.

An APK is essentially just a zip file so you can extract it with any zip tool.

The list of architectures (ABIs) is here. If you don't have directories for arm64-v8a or have x86 but don't have x86_64 then you are missing the 64 bit native code.