[TurboModule] Setup the NDK Build for the Android app

Author: cortinico

android/app/build.gradle

@@ -145,7 +145,29 @@ android {
         targetSdkVersion rootProject.ext.targetSdkVersion
         versionCode 1
         versionName "1.0"
+
+        externalNativeBuild {
+            ndkBuild {
+                arguments "APP_PLATFORM=android-21",
+                        "APP_STL=c++_shared",
+                        "NDK_TOOLCHAIN_VERSION=clang",
+                        "GENERATED_SRC_DIR=$buildDir/generated/source",
+                        "PROJECT_BUILD_DIR=$buildDir",
+                        "REACT_ANDROID_DIR=$rootDir/../node_modules/react-native/ReactAndroid",
+                        "REACT_ANDROID_BUILD_DIR=$rootDir/../node_modules/react-native/ReactAndroid/build"
+                cFlags "-Wall", "-Werror", "-fexceptions", "-frtti", "-DWITH_INSPECTOR=1"
+                cppFlags "-std=c++17"
+                targets "rnnewarchitectureapp_appmodules"
+            }
+        }
+    }
+
+    externalNativeBuild {
+        ndkBuild {
+            path "$projectDir/src/main/jni/Android.mk"
+        }
     }
+
     splits {
         abi {
             reset()
@@ -196,6 +218,20 @@ android {
         }
     }
 
+    def reactAndroidProjectDir = project(':ReactAndroid').projectDir
+    def packageReactNdkLibs = tasks.register("packageReactNdkLibs", Copy) {
+        dependsOn(":ReactAndroid:packageReactNdkLibsForBuck")
+        dependsOn("generateCodegenArtifactsFromSchema")
+        from("$reactAndroidProjectDir/src/main/jni/prebuilt/lib")
+        into("$buildDir/react-ndk/exported")
+    }
+
+    afterEvaluate {
+        preBuild.dependsOn(packageReactNdkLibs)
+        configureNdkBuildDebug.dependsOn(preBuild)
+        configureNdkBuildRelease.dependsOn(preBuild)
+    }
+
     packagingOptions {
         pickFirst '**/libhermes.so'
         pickFirst '**/libjsc.so'

android/app/src/main/jni/Android.mk

@@ -0,0 +1,41 @@
+THIS_DIR := $(call my-dir)
+
+include $(REACT_ANDROID_DIR)/Android-prebuilt.mk
+include $(GENERATED_SRC_DIR)/codegen/jni/Android.mk
+
+include $(CLEAR_VARS)
+
+LOCAL_PATH := $(THIS_DIR)
+LOCAL_MODULE := rnnewarchitectureapp_appmodules
+
+LOCAL_C_INCLUDES := $(LOCAL_PATH) $(GENERATED_SRC_DIR)/codegen/jni
+LOCAL_SRC_FILES := $(wildcard $(LOCAL_PATH)/*.cpp) $(wildcard $(GENERATED_SRC_DIR)/codegen/jni/*.cpp)
+LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH) $(GENERATED_SRC_DIR)/codegen/jni
+
+# Please note as one of the library listed is libreact_codegen_answersolver
+# This name will be generated as libreact_codegen_<library-name>
+# where <library-name> is the one you specified in the Gradle configuration
+LOCAL_SHARED_LIBRARIES := libjsi \
+    libfbjni \
+    libglog \
+    libfolly_json \
+    libyoga \
+    libreact_nativemodule_core \
+    libturbomodulejsijni \
+    librrc_view \
+    libreact_render_core \
+    libreact_render_graphics \
+    libfabricjni \
+    libfolly_futures \
+    libreact_debug \
+    libreact_render_componentregistry \
+    libreact_render_debug \
+    libruntimeexecutor \
+    libreact_codegen_rncore \
+    react_codegen_answersolver
+
+LOCAL_CFLAGS := \
+    -DLOG_TAG=\"ReactNative\"
+LOCAL_CFLAGS += -fexceptions -frtti -std=c++17 -Wall
+
+include $(BUILD_SHARED_LIBRARY)