Setup a newArchEnabled property to Opt-in the New Architecture in the template (#32790)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/32790

As the name says, I've added a `newArchEnabled` property that can be used to toggle the
New Architecture in the new app template. Users can use this to try the New Architecture in their
project by either:
* Set `newArchEnabled` to true inside the `gradle.properties` file
* Invoke gradle with `-PnewArchEnabled=true`
* Set an environment variable `ORG_GRADLE_PROJECT_newArchEnabled=true`

The Project property will also control if:
* ReactNative dependency should be built from source or not.
* The NDK should be enabled or not.

Please note that this requires RN 0.68.x to run properly (it won't work with 0.67 RCs) or a Nightly version of React Native.

Changelog:
[Android] [Added] - Setup a `newArchEnabled` property to Opt-in the New Architecture in the template

Reviewed By: ShikaSD

Differential Revision: D33065373

fbshipit-source-id: 32085f5b071d6243936bafd91425b5b43e5b5101

settings.gradle.kts

@@ -21,9 +21,3 @@ include(
 // Include this to enable codegen Gradle plugin.
 includeBuild("packages/react-native-gradle-plugin/")
 
-// Include this to build the Android template as well and make sure is not broken.
-if (File("template/node_modules/").exists()) {
-    includeBuild("template/android/") {
-        name = "template-android"
-    }
-}

template/android/app/build.gradle

@@ -139,7 +139,56 @@ android {
         targetSdkVersion rootProject.ext.targetSdkVersion
         versionCode 1
         versionName "1.0"
+        buildConfigField "boolean", "IS_NEW_ARCHITECTURE_ENABLED", isNewArchitectureEnabled().toString()
+
+        if (isNewArchitectureEnabled()) {
+            // We configure the NDK build only if you decide to opt-in for the New Architecture.
+            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"
+                    // Make sure this target name is the same you specify inside the
+                    // src/main/jni/Android.mk file for the `LOCAL_MODULE` variable.
+                    targets "helloworld_appmodules"
+                }
+            }
+        }
     }
+
+    if (isNewArchitectureEnabled()) {
+        // We configure the NDK build only if you decide to opt-in for the New Architecture.
+        externalNativeBuild {
+            ndkBuild {
+                path "$projectDir/src/main/jni/Android.mk"
+            }
+        }
+        def reactAndroidProjectDir = project(':ReactAndroid').projectDir
+        def packageReactNdkDebugLibs = tasks.register("packageReactNdkDebugLibs", Copy) {
+            dependsOn(":ReactAndroid:packageReactNdkDebugLibsForBuck")
+            from("$reactAndroidProjectDir/src/main/jni/prebuilt/lib")
+            into("$buildDir/react-ndk/exported")
+        }
+        def packageReactNdkReleaseLibs = tasks.register("packageReactNdkReleaseLibs", Copy) {
+            dependsOn(":ReactAndroid:packageReactNdkReleaseLibsForBuck")
+            from("$reactAndroidProjectDir/src/main/jni/prebuilt/lib")
+            into("$buildDir/react-ndk/exported")
+        }
+        afterEvaluate {
+            // If you wish to add a custom TurboModule or component locally,
+            // you should uncomment this line.
+            // preBuild.dependsOn("generateCodegenArtifactsFromSchema")
+            preDebugBuild.dependsOn(packageReactNdkDebugLibs)
+            preReleaseBuild.dependsOn(packageReactNdkReleaseLibs)
+        }
+    }
+
     splits {
         abi {
             reset()
@@ -193,8 +242,15 @@ android {
 
 dependencies {
     implementation fileTree(dir: "libs", include: ["*.jar"])
-    //noinspection GradleDynamicVersion
-    implementation "com.facebook.react:react-native:+"  // From node_modules
+
+    // If new architecture is enabled, we let you build RN from source
+    // Otherwise we fallback to a prebuilt .aar bundled in the NPM package.
+    if (isNewArchitectureEnabled()) {
+        implementation project(":ReactAndroid")
+    } else {
+        //noinspection GradleDynamicVersion
+        implementation "com.facebook.react:react-native:+"  // From node_modules
+    }
 
     implementation "androidx.swiperefreshlayout:swiperefreshlayout:1.0.0"
 
@@ -228,3 +284,11 @@ task copyDownloadableDepsToLibs(type: Copy) {
 }
 
 apply from: file("../../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesAppBuildGradle(project)
+
+def isNewArchitectureEnabled() {
+    // To opt-in for the New Architecture, you can either:
+    // - Set `newArchEnabled` to true inside the `gradle.properties` file
+    // - Invoke gradle with `-newArchEnabled=true`
+    // - Set an environment variable `ORG_GRADLE_PROJECT_newArchEnabled=true`
+    return project.hasProperty("newArchEnabled") && project.newArchEnabled == "true"
+}

template/android/app/src/main/java/com/helloworld/MainActivity.java

@@ -1,6 +1,8 @@
 package com.helloworld;
 
 import com.facebook.react.ReactActivity;
+import com.facebook.react.ReactActivityDelegate;
+import com.facebook.react.ReactRootView;
 
 public class MainActivity extends ReactActivity {
 
@@ -12,4 +14,27 @@ public class MainActivity extends ReactActivity {
   protected String getMainComponentName() {
     return "HelloWorld";
   }
+
+  /**
+   * Returns the instance of the {@link ReactActivityDelegate}. There the RootView is created and
+   * you can specify the rendered you wish to use (Fabric or the older renderer).
+   */
+  @Override
+  protected ReactActivityDelegate createReactActivityDelegate() {
+    return new MainActivityDelegate(this, getMainComponentName());
+  }
+
+  public static class MainActivityDelegate extends ReactActivityDelegate {
+    public MainActivityDelegate(ReactActivity activity, String mainComponentName) {
+      super(activity, mainComponentName);
+    }
+
+    @Override
+    protected ReactRootView createRootView() {
+      ReactRootView reactRootView = new ReactRootView(getContext());
+      // If you opted-in for the New Architecture, we enable the Fabric Renderer.
+      reactRootView.setIsFabric(BuildConfig.IS_NEW_ARCHITECTURE_ENABLED);
+      return reactRootView;
+    }
+  }
 }

template/android/app/src/main/java/com/helloworld/MainApplication.java

@@ -7,7 +7,9 @@ import com.facebook.react.ReactApplication;
 import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactNativeHost;
 import com.facebook.react.ReactPackage;
+import com.facebook.react.config.ReactFeatureFlags;
 import com.facebook.soloader.SoLoader;
+import com.helloworld.newarchitecture.MainApplicationReactNativeHost;
 import java.lang.reflect.InvocationTargetException;
 import java.util.List;
 
@@ -35,14 +37,23 @@ public class MainApplication extends Application implements ReactApplication {
         }
       };
 
+  private final ReactNativeHost mNewArchitectureNativeHost =
+      new MainApplicationReactNativeHost(this);
+
   @Override
   public ReactNativeHost getReactNativeHost() {
-    return mReactNativeHost;
+    if (BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
+      return mNewArchitectureNativeHost;
+    } else {
+      return mReactNativeHost;
+    }
   }
 
   @Override
   public void onCreate() {
     super.onCreate();
+    // If you opted-in for the New Architecture, we enable the TurboModule system
+    ReactFeatureFlags.useTurboModules = BuildConfig.IS_NEW_ARCHITECTURE_ENABLED;
     SoLoader.init(this, /* native exopackage */ false);
     initializeFlipper(this, getReactNativeHost().getReactInstanceManager());
   }

template/android/app/src/main/java/com/helloworld/newarchitecture/MainApplicationReactNativeHost.java

@@ -0,0 +1,116 @@
+package com.helloworld.newarchitecture;
+
+import android.app.Application;
+import androidx.annotation.NonNull;
+import com.facebook.react.PackageList;
+import com.facebook.react.ReactInstanceManager;
+import com.facebook.react.ReactNativeHost;
+import com.facebook.react.ReactPackage;
+import com.facebook.react.ReactPackageTurboModuleManagerDelegate;
+import com.facebook.react.bridge.JSIModulePackage;
+import com.facebook.react.bridge.JSIModuleProvider;
+import com.facebook.react.bridge.JSIModuleSpec;
+import com.facebook.react.bridge.JSIModuleType;
+import com.facebook.react.bridge.JavaScriptContextHolder;
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.react.bridge.UIManager;
+import com.facebook.react.fabric.ComponentFactory;
+import com.facebook.react.fabric.CoreComponentsRegistry;
+import com.facebook.react.fabric.EmptyReactNativeConfig;
+import com.facebook.react.fabric.FabricJSIModuleProvider;
+import com.facebook.react.uimanager.ViewManagerRegistry;
+import com.helloworld.BuildConfig;
+import com.helloworld.newarchitecture.components.MainComponentsRegistry;
+import com.helloworld.newarchitecture.modules.MainApplicationTurboModuleManagerDelegate;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A {@link ReactNativeHost} that helps you load everything needed for the New Architecture, both
+ * TurboModule delegates and the Fabric Renderer.
+ *
+ * <p>Please note that this class is used ONLY if you opt-in for the New Architecture (see the
+ * `newArchEnabled` property). Is ignored otherwise.
+ */
+public class MainApplicationReactNativeHost extends ReactNativeHost {
+  public MainApplicationReactNativeHost(Application application) {
+    super(application);
+  }
+
+  @Override
+  public boolean getUseDeveloperSupport() {
+    return BuildConfig.DEBUG;
+  }
+
+  @Override
+  protected List<ReactPackage> getPackages() {
+    List<ReactPackage> packages = new PackageList(this).getPackages();
+    // Packages that cannot be autolinked yet can be added manually here, for example:
+    //     packages.add(new MyReactNativePackage());
+    // TurboModules must also be loaded here providing a valid TurboReactPackage implementation:
+    //     packages.add(new TurboReactPackage() { ... });
+    // If you have custom Fabric Components, their ViewManagers should also be loaded here
+    // inside a ReactPackage.
+    return packages;
+  }
+
+  @Override
+  protected String getJSMainModuleName() {
+    return "index";
+  }
+
+  @NonNull
+  @Override
+  protected ReactPackageTurboModuleManagerDelegate.Builder
+      getReactPackageTurboModuleManagerDelegateBuilder() {
+    // Here we provide the ReactPackageTurboModuleManagerDelegate Builder. This is necessary
+    // for the new architecture and to use TurboModules correctly.
+    return new MainApplicationTurboModuleManagerDelegate.Builder();
+  }
+
+  @Override
+  protected JSIModulePackage getJSIModulePackage() {
+    return new JSIModulePackage() {
+      @Override
+      public List<JSIModuleSpec> getJSIModules(
+          final ReactApplicationContext reactApplicationContext,
+          final JavaScriptContextHolder jsContext) {
+        final List<JSIModuleSpec> specs = new ArrayList<>();
+
+        // Here we provide a new JSIModuleSpec that will be responsible of providing the
+        // custom Fabric Components.
+        specs.add(
+            new JSIModuleSpec() {
+              @Override
+              public JSIModuleType getJSIModuleType() {
+                return JSIModuleType.UIManager;
+              }
+
+              @Override
+              public JSIModuleProvider<UIManager> getJSIModuleProvider() {
+                final ComponentFactory componentFactory = new ComponentFactory();
+                CoreComponentsRegistry.register(componentFactory);
+
+                // Here we register a Components Registry.
+                // The one that is generated with the template contains no components
+                // and just provides you the one from React Native core.
+                MainComponentsRegistry.register(componentFactory);
+
+                final ReactInstanceManager reactInstanceManager = getReactInstanceManager();
+
+                ViewManagerRegistry viewManagerRegistry =
+                    new ViewManagerRegistry(
+                        reactInstanceManager.getOrCreateViewManagers(reactApplicationContext));
+
+                return new FabricJSIModuleProvider(
+                    reactApplicationContext,
+                    componentFactory,
+                    new EmptyReactNativeConfig(),
+                    viewManagerRegistry);
+              }
+            });
+        return specs;
+      }
+    };
+  }
+}

template/android/app/src/main/java/com/helloworld/newarchitecture/components/MainComponentsRegistry.java

@@ -0,0 +1,36 @@
+package com.helloworld.newarchitecture.components;
+
+import com.facebook.jni.HybridData;
+import com.facebook.proguard.annotations.DoNotStrip;
+import com.facebook.react.fabric.ComponentFactory;
+import com.facebook.soloader.SoLoader;
+
+/**
+ * Class responsible to load the custom Fabric Components. This class has native methods and needs a
+ * corresponding C++ implementation/header file to work correctly (already placed inside the jni/
+ * folder for you).
+ *
+ * <p>Please note that this class is used ONLY if you opt-in for the New Architecture (see the
+ * `newArchEnabled` property). Is ignored otherwise.
+ */
+@DoNotStrip
+public class MainComponentsRegistry {
+  static {
+    SoLoader.loadLibrary("fabricjni");
+  }
+
+  @DoNotStrip private final HybridData mHybridData;
+
+  @DoNotStrip
+  private native HybridData initHybrid(ComponentFactory componentFactory);
+
+  @DoNotStrip
+  private MainComponentsRegistry(ComponentFactory componentFactory) {
+    mHybridData = initHybrid(componentFactory);
+  }
+
+  @DoNotStrip
+  public static MainComponentsRegistry register(ComponentFactory componentFactory) {
+    return new MainComponentsRegistry(componentFactory);
+  }
+}

template/android/app/src/main/java/com/helloworld/newarchitecture/modules/MainApplicationTurboModuleManagerDelegate.java

@@ -0,0 +1,48 @@
+package com.helloworld.newarchitecture.modules;
+
+import com.facebook.jni.HybridData;
+import com.facebook.react.ReactPackage;
+import com.facebook.react.ReactPackageTurboModuleManagerDelegate;
+import com.facebook.react.bridge.ReactApplicationContext;
+import com.facebook.soloader.SoLoader;
+import java.util.List;
+
+/**
+ * Class responsible to load the TurboModules. This class has native methods and needs a
+ * corresponding C++ implementation/header file to work correctly (already placed inside the jni/
+ * folder for you).
+ *
+ * <p>Please note that this class is used ONLY if you opt-in for the New Architecture (see the
+ * `newArchEnabled` property). Is ignored otherwise.
+ */
+public class MainApplicationTurboModuleManagerDelegate
+    extends ReactPackageTurboModuleManagerDelegate {
+
+  private static volatile boolean sIsSoLibraryLoaded;
+
+  protected MainApplicationTurboModuleManagerDelegate(
+      ReactApplicationContext reactApplicationContext, List<ReactPackage> packages) {
+    super(reactApplicationContext, packages);
+  }
+
+  protected native HybridData initHybrid();
+
+  native boolean canCreateTurboModule(String moduleName);
+
+  public static class Builder extends ReactPackageTurboModuleManagerDelegate.Builder {
+    protected MainApplicationTurboModuleManagerDelegate build(
+        ReactApplicationContext context, List<ReactPackage> packages) {
+      return new MainApplicationTurboModuleManagerDelegate(context, packages);
+    }
+  }
+
+  @Override
+  protected synchronized void maybeLoadOtherSoLibraries() {
+    if (!sIsSoLibraryLoaded) {
+      // If you change the name of your application .so file in the Android.mk file,
+      // make sure you update the name here as well.
+      SoLoader.loadLibrary("helloworld_appmodules");
+      sIsSoLibraryLoaded = true;
+    }
+  }
+}

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

@@ -0,0 +1,49 @@
+THIS_DIR := $(call my-dir)
+
+include $(REACT_ANDROID_DIR)/Android-prebuilt.mk
+
+# If you wish to add a custom TurboModule or Fabric component in your app you
+# will have to include the following autogenerated makefile.
+# include $(GENERATED_SRC_DIR)/codegen/jni/Android.mk
+include $(CLEAR_VARS)
+
+LOCAL_PATH := $(THIS_DIR)
+
+# You can customize the name of your application .so file here.
+LOCAL_MODULE := helloworld_appmodules
+
+LOCAL_C_INCLUDES := $(LOCAL_PATH)
+LOCAL_SRC_FILES := $(wildcard $(LOCAL_PATH)/*.cpp)
+LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)
+
+# If you wish to add a custom TurboModule or Fabric component in your app you
+# will have to uncomment those lines to include the generated source 
+# files from the codegen (placed in $(GENERATED_SRC_DIR)/codegen/jni)
+#
+# LOCAL_C_INCLUDES += $(GENERATED_SRC_DIR)/codegen/jni
+# LOCAL_SRC_FILES += $(wildcard $(GENERATED_SRC_DIR)/codegen/jni/*.cpp)
+# LOCAL_EXPORT_C_INCLUDES += $(GENERATED_SRC_DIR)/codegen/jni
+
+# Here you should add any native library you wish to depend on.
+LOCAL_SHARED_LIBRARIES := \
+  libfabricjni \
+  libfbjni \
+  libfolly_futures \
+  libfolly_json \
+  libglog \
+  libjsi \
+  libreact_codegen_rncore \
+  libreact_debug \
+  libreact_nativemodule_core \
+  libreact_render_componentregistry \
+  libreact_render_core \
+  libreact_render_debug \
+  libreact_render_graphics \
+  librrc_view \
+  libruntimeexecutor \
+  libturbomodulejsijni \
+  libyoga
+
+LOCAL_CFLAGS := -DLOG_TAG=\"ReactNative\" -fexceptions -frtti -std=c++17 -Wall
+
+include $(BUILD_SHARED_LIBRARY)

template/android/app/src/main/jni/MainApplicationModuleProvider.cpp

@@ -0,0 +1,24 @@
+#include "MainApplicationModuleProvider.h"
+
+#include <rncore.h>
+
+namespace facebook {
+namespace react {
+
+std::shared_ptr<TurboModule> MainApplicationModuleProvider(
+    const std::string moduleName,
+    const JavaTurboModule::InitParams &params) {
+  // Here you can provide your own module provider for TurboModules coming from
+  // either your application or from external libraries. The approach to follow
+  // is similar to the following (for a library called `samplelibrary`:
+  //
+  // auto module = samplelibrary_ModuleProvider(moduleName, params);
+  // if (module != nullptr) {
+  //    return module;
+  // }
+  // return rncore_ModuleProvider(moduleName, params);
+  return rncore_ModuleProvider(moduleName, params);
+}
+
+} // namespace react
+} // namespace facebook

template/android/app/src/main/jni/MainApplicationModuleProvider.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <memory>
+#include <string>
+
+#include <ReactCommon/JavaTurboModule.h>
+
+namespace facebook {
+namespace react {
+
+std::shared_ptr<TurboModule> MainApplicationModuleProvider(
+    const std::string moduleName,
+    const JavaTurboModule::InitParams &params);
+
+} // namespace react
+} // namespace facebook

template/android/app/src/main/jni/MainApplicationTurboModuleManagerDelegate.cpp

@@ -0,0 +1,45 @@
+#include "MainApplicationTurboModuleManagerDelegate.h"
+#include "MainApplicationModuleProvider.h"
+
+namespace facebook {
+namespace react {
+
+jni::local_ref<MainApplicationTurboModuleManagerDelegate::jhybriddata>
+MainApplicationTurboModuleManagerDelegate::initHybrid(
+    jni::alias_ref<jhybridobject>) {
+  return makeCxxInstance();
+}
+
+void MainApplicationTurboModuleManagerDelegate::registerNatives() {
+  registerHybrid({
+      makeNativeMethod(
+          "initHybrid", MainApplicationTurboModuleManagerDelegate::initHybrid),
+      makeNativeMethod(
+          "canCreateTurboModule",
+          MainApplicationTurboModuleManagerDelegate::canCreateTurboModule),
+  });
+}
+
+std::shared_ptr<TurboModule>
+MainApplicationTurboModuleManagerDelegate::getTurboModule(
+    const std::string name,
+    const std::shared_ptr<CallInvoker> jsInvoker) {
+  // Not implemented yet: provide pure-C++ NativeModules here.
+  return nullptr;
+}
+
+std::shared_ptr<TurboModule>
+MainApplicationTurboModuleManagerDelegate::getTurboModule(
+    const std::string name,
+    const JavaTurboModule::InitParams &params) {
+  return MainApplicationModuleProvider(name, params);
+}
+
+bool MainApplicationTurboModuleManagerDelegate::canCreateTurboModule(
+    std::string name) {
+  return getTurboModule(name, nullptr) != nullptr ||
+      getTurboModule(name, {.moduleName = name}) != nullptr;
+}
+
+} // namespace react
+} // namespace facebook

template/android/app/src/main/jni/MainApplicationTurboModuleManagerDelegate.h

@@ -0,0 +1,38 @@
+#include <memory>
+#include <string>
+
+#include <ReactCommon/TurboModuleManagerDelegate.h>
+#include <fbjni/fbjni.h>
+
+namespace facebook {
+namespace react {
+
+class MainApplicationTurboModuleManagerDelegate
+    : public jni::HybridClass<
+          MainApplicationTurboModuleManagerDelegate,
+          TurboModuleManagerDelegate> {
+ public:
+  // Adapt it to the package you used for your Java class.
+  static constexpr auto kJavaDescriptor =
+      "Lcom/helloworld/newarchitecture/modules/MainApplicationTurboModuleManagerDelegate;";
+
+  static jni::local_ref<jhybriddata> initHybrid(jni::alias_ref<jhybridobject>);
+
+  static void registerNatives();
+
+  std::shared_ptr<TurboModule> getTurboModule(
+      const std::string name,
+      const std::shared_ptr<CallInvoker> jsInvoker) override;
+  std::shared_ptr<TurboModule> getTurboModule(
+      const std::string name,
+      const JavaTurboModule::InitParams &params) override;
+
+  /**
+   * Test-only method. Allows user to verify whether a TurboModule can be
+   * created by instances of this class.
+   */
+  bool canCreateTurboModule(std::string name);
+};
+
+} // namespace react
+} // namespace facebook

template/android/app/src/main/jni/MainComponentsRegistry.cpp

@@ -0,0 +1,61 @@
+#include "MainComponentsRegistry.h"
+
+#include <CoreComponentsRegistry.h>
+#include <fbjni/fbjni.h>
+#include <react/renderer/componentregistry/ComponentDescriptorProviderRegistry.h>
+#include <react/renderer/components/rncore/ComponentDescriptors.h>
+
+namespace facebook {
+namespace react {
+
+MainComponentsRegistry::MainComponentsRegistry(ComponentFactory *delegate) {}
+
+std::shared_ptr<ComponentDescriptorProviderRegistry const>
+MainComponentsRegistry::sharedProviderRegistry() {
+  auto providerRegistry = CoreComponentsRegistry::sharedProviderRegistry();
+
+  // Custom Fabric Components go here. You can register custom
+  // components coming from your App or from 3rd party libraries here.
+  //
+  // providerRegistry->add(concreteComponentDescriptorProvider<
+  //        AocViewerComponentDescriptor>());
+  return providerRegistry;
+}
+
+jni::local_ref<MainComponentsRegistry::jhybriddata>
+MainComponentsRegistry::initHybrid(
+    jni::alias_ref<jclass>,
+    ComponentFactory *delegate) {
+  auto instance = makeCxxInstance(delegate);
+
+  auto buildRegistryFunction =
+      [](EventDispatcher::Weak const &eventDispatcher,
+         ContextContainer::Shared const &contextContainer)
+      -> ComponentDescriptorRegistry::Shared {
+    auto registry = MainComponentsRegistry::sharedProviderRegistry()
+                        ->createComponentDescriptorRegistry(
+                            {eventDispatcher, contextContainer});
+
+    auto mutableRegistry =
+        std::const_pointer_cast<ComponentDescriptorRegistry>(registry);
+
+    mutableRegistry->setFallbackComponentDescriptor(
+        std::make_shared<UnimplementedNativeViewComponentDescriptor>(
+            ComponentDescriptorParameters{
+                eventDispatcher, contextContainer, nullptr}));
+
+    return registry;
+  };
+
+  delegate->buildRegistryFunction = buildRegistryFunction;
+  return instance;
+}
+
+void MainComponentsRegistry::registerNatives() {
+  registerHybrid({
+      makeNativeMethod("initHybrid", MainComponentsRegistry::initHybrid),
+  });
+}
+
+} // namespace react
+} // namespace facebook

template/android/app/src/main/jni/MainComponentsRegistry.h

@@ -0,0 +1,32 @@
+#pragma once
+
+#include <ComponentFactory.h>
+#include <fbjni/fbjni.h>
+#include <react/renderer/componentregistry/ComponentDescriptorProviderRegistry.h>
+#include <react/renderer/componentregistry/ComponentDescriptorRegistry.h>
+
+namespace facebook {
+namespace react {
+
+class MainComponentsRegistry
+    : public facebook::jni::HybridClass<MainComponentsRegistry> {
+ public:
+  // Adapt it to the package you used for your Java class.
+  constexpr static auto kJavaDescriptor =
+      "Lcom/helloworld/newarchitecture/components/MainComponentsRegistry;";
+
+  static void registerNatives();
+
+  MainComponentsRegistry(ComponentFactory *delegate);
+
+ private:
+  static std::shared_ptr<ComponentDescriptorProviderRegistry const>
+  sharedProviderRegistry();
+
+  static jni::local_ref<jhybriddata> initHybrid(
+      jni::alias_ref<jclass>,
+      ComponentFactory *delegate);
+};
+
+} // namespace react
+} // namespace facebook

template/android/app/src/main/jni/OnLoad.cpp

@@ -0,0 +1,11 @@
+#include <fbjni/fbjni.h>
+#include "MainApplicationTurboModuleManagerDelegate.h"
+#include "MainComponentsRegistry.h"
+
+JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM *vm, void *) {
+  return facebook::jni::initialize(vm, [] {
+    facebook::react::MainApplicationTurboModuleManagerDelegate::
+        registerNatives();
+    facebook::react::MainComponentsRegistry::registerNatives();
+  });
+}

template/android/build.gradle

@@ -14,6 +14,8 @@ buildscript {
     }
     dependencies {
         classpath("com.android.tools.build:gradle:7.0.1")
+        classpath("com.facebook.react:react")
+        classpath("de.undercouch:gradle-download-task:4.1.1")
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }

template/android/gradle.properties

@@ -31,3 +31,10 @@ FLIPPER_VERSION=0.99.0
 # You can also override it from the CLI using
 # ./gradlew <task> -PreactNativeArchitectures=x86_64
 reactNativeArchitectures=armeabi-v7a,arm64-v8a,x86,x86_64
+
+# Use this property to enable support to the new architecture.
+# This will allow you to use TurboModules and the Fabric render in
+# your application. You should enable this flag either if you want
+# to write custom TurboModules/Fabric components OR use libraries that
+# are providing them.
+newArchEnabled=false

template/android/settings.gradle

@@ -1,3 +1,13 @@
 rootProject.name = 'HelloWorld'
 apply from: file("../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesSettingsGradle(settings)
 include ':app'
+includeBuild('../node_modules/react-native-gradle-plugin') {
+    dependencySubstitution {
+        substitute(module("com.facebook.react:react")).using(project(":"))
+    }
+}
+
+if (settings.hasProperty("newArchEnabled") && settings.newArchEnabled == "true") {
+    include(":ReactAndroid")
+    project(":ReactAndroid").projectDir = file('../node_modules/react-native/ReactAndroid')
+}

template/package.json

@@ -21,6 +21,7 @@
     "eslint": "^7.32.0",
     "jest": "^26.6.3",
     "metro-react-native-babel-preset": "^0.66.2",
+    "react-native-gradle-plugin": "^0.0.3",
     "react-test-renderer": "17.0.2"
   },
   "jest": {