Undefined reference to 'facebook::react::MapBufferBuilder::EMPTY()'

[grahammendick]

I’m trying to migrate updateNodeSize on Android to the new architecture but I’m stuck. I managed to migrate setSize on iOS to the new architecture but can’t get it working on Android. I’ve found it a real struggle because c++/rendered state isn’t documented anywhere.

I set interfaceOnly to true in the NativeComponent.js spec. Then I hand-wrote 5 classes for my component - ComponentDescriptor.h, ShadowNode.h, ShadowNode.cpp, State.h and State.cpp.

On iOS, after I included these 5 files in the source_files of the podspec, I could successfully updateState.

On Android I copied these 5 files into the codegen directory so they were included along with the generated files. But when I 'run-android' I get the error undefined reference to 'facebook::react::MapBufferBuilder::EMPTY()'. The error points to my State.h file where I'm returning MapBufferBuilder::EMPTY() from getMapBuffer as per the React Native Modal example.

I have no idea if what I’m doing is correct. Please help me out.

[grahammendick]

I got rid of the error by adding libreact_render_mapbuffer \ to LOCAL_SHARED_LIBRARIES of the app's Android.mk (in android/app/src/main/jni/). But I still have no idea what I'm doing.

[grahammendick]

What's the right way to get the 5 hand-written files included along with the generated ones? Do I need to write a custom Android.mk?

[grahammendick]

I didn't write a custom Android.mk. Instead I edited the LOCAL_C_INCLUDES, LOCAL_SRC_FILES, LOCAL_EXPORT_C_INCLUDES in the app's Android.mk to point to the folder that contains my 5 hand-written files. Is that ok? Will this still work when autolinking on Android lands?

[grahammendick]

The first run-android takes much longer after editing the LOCAL_C_INCLUDES, LOCAL_SRC_FILES, LOCAL_EXPORT_C_INCLUDES in the app's Android.mk. About twice as long. Why is that?

[grahammendick]

See my guide on c++ state in Fabric (but I've got no answer for why the build takes longer)