MainActivity.java - cannot find symbol reactRootView.setIsFabric(BuildConfig.IS_NEW_ARCHITECTURE_ENABLED)

Question

I've upgraded react-native to latest version (0.68) through react-native CLI, and now every time I'm trying to build for android I get this error: error: cannot find symbol reactRootView.setIsFabric(BuildConfig.IS_NEW_ARCHITECTURE_ENABLED);

I tried to clean the bundle, made sure my package name is correct (like others issues suggested) and nothing so far..

Answer 1

Going through react-native migrations file, I've found out that somehow I missed a few migrations related to react-native new architecture (although I would expect it to be automatic when using react-native CLI upgrade command).

I suggest to follow the migrations changes especially on MainActivity.java and MainApplication.java - don't forget to change the "from" and "to" versions to your case:

https://react-native-community.github.io/upgrade-helper/?from=0.65.1&to=0.68.1

Answer 2

I Was Having Same Issues I changed My React Native Version to 0.72.5

Deleted node_modules using rm -rf node_modules Installed It using yarn yarn

Then Made the below mentioned changes in

/Users/username/pathToProject/android/app/src/main/java/com/app/MainApplication.java

And

/Users/username/pathToProject/android/app/src/main/java/com/app/MainActivity.java

Then In MainApplication.java

 package Your Package Name;

import android.app.Application;
import android.content.res.Configuration;
import androidx.annotation.NonNull;

import com.facebook.react.PackageList;
import com.facebook.react.ReactApplication;
import com.facebook.react.ReactNativeHost;
import com.facebook.react.ReactPackage;
import com.facebook.react.config.ReactFeatureFlags;
import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint;
import com.facebook.react.defaults.DefaultReactNativeHost;
import com.facebook.soloader.SoLoader;

import expo.modules.ApplicationLifecycleDispatcher;
import expo.modules.ReactNativeHostWrapper;

import java.util.List;

public class MainApplication extends Application implements ReactApplication {

  private final ReactNativeHost mReactNativeHost =
    new ReactNativeHostWrapper(this, new DefaultReactNativeHost(this) {
      @Override
      public boolean getUseDeveloperSupport() {
        return BuildConfig.DEBUG;
      }

      @Override
      protected List<ReactPackage> getPackages() {
        @SuppressWarnings("UnnecessaryLocalVariable")
        List<ReactPackage> packages = new PackageList(this).getPackages();
        // Packages that cannot be autolinked yet can be added manually here, for example:
        // packages.add(new MyReactNativePackage());
        // packages.add(new RNFirebaseMessagingPackage());
        // packages.add(new RNFirebaseNotificationsPackage());
        return packages;
      }

      @Override
      protected String getJSMainModuleName() {
        return ".expo/.virtual-metro-entry";
      }

      @Override
      protected boolean isNewArchEnabled() {
        return BuildConfig.IS_NEW_ARCHITECTURE_ENABLED;
      }

      @Override
      protected Boolean isHermesEnabled() {
        return BuildConfig.IS_HERMES_ENABLED;
      }
  });

  @Override
  public ReactNativeHost getReactNativeHost() {
    return mReactNativeHost;
  }

  @Override
  public void onCreate() {
    super.onCreate();
    SoLoader.init(this, /* native exopackage */ false);
    if (!BuildConfig.REACT_NATIVE_UNSTABLE_USE_RUNTIME_SCHEDULER_ALWAYS) {
      ReactFeatureFlags.unstable_useRuntimeSchedulerAlways = false;
    }
    if (BuildConfig.IS_NEW_ARCHITECTURE_ENABLED) {
      // If you opted-in for the New Architecture, we load the native entry point for this app.
      DefaultNewArchitectureEntryPoint.load();
    }
    ReactNativeFlipper.initializeFlipper(this, getReactNativeHost().getReactInstanceManager());
    ApplicationLifecycleDispatcher.onApplicationCreate(this);
  }

  @Override
  public void onConfigurationChanged(@NonNull Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    ApplicationLifecycleDispatcher.onConfigurationChanged(this, newConfig);
  }
}

And Then In MainActivity.java

    package yourpackageName;

import android.os.Build;
import android.os.Bundle;

import com.facebook.react.ReactActivity;
import com.facebook.react.ReactActivityDelegate;
import com.facebook.react.defaults.DefaultNewArchitectureEntryPoint;
import com.facebook.react.defaults.DefaultReactActivityDelegate;

import expo.modules.ReactActivityDelegateWrapper;

public class MainActivity extends ReactActivity {
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    // Set the theme to AppTheme BEFORE onCreate to support 
    // coloring the background, status bar, and navigation bar.
    // This is required for expo-splash-screen.
    setTheme(R.style.AppTheme);
    super.onCreate(null);
  }

  /**
   * Returns the name of the main component registered from JavaScript.
   * This is used to schedule rendering of the component.
   */
  @Override
  protected String getMainComponentName() {
    return "main";
  }

  /**
   * Returns the instance of the {@link ReactActivityDelegate}. Here we use a util class {@link
   * DefaultReactActivityDelegate} which allows you to easily enable Fabric and Concurrent React
   * (aka React 18) with two boolean flags.
   */
  @Override
  protected ReactActivityDelegate createReactActivityDelegate() {
    return new ReactActivityDelegateWrapper(this, BuildConfig.IS_NEW_ARCHITECTURE_ENABLED, new DefaultReactActivityDelegate(
        this,
        getMainComponentName(),
        // If you opted-in for the New Architecture, we enable the Fabric Renderer.
        DefaultNewArchitectureEntryPoint.getFabricEnabled()));
  }

  /**
   * Align the back button behavior with Android S
   * where moving root activities to background instead of finishing activities.
   * @see <a href="https://developer.android.com/reference/android/app/Activity#onBackPressed()">onBackPressed</a>
   */
  @Override
  public void invokeDefaultOnBackPressed() {
    if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.R) {
      if (!moveTaskToBack(false)) {
        // For non-root activities, use the default implementation to finish them.
        super.invokeDefaultOnBackPressed();
      }
      return;
    }

    // Use the default back button implementation on Android S
    // because it's doing more than {@link Activity#moveTaskToBack} in fact.
    super.invokeDefaultOnBackPressed();
  }
}

Answer 3

If you're using the latest version of React Native (i.e: v >= 68), you've to rebuild your projects. it works for me.

Answer 4

Inside your .env file add those keys and then give them boolean values, like the following:

IS_NEW_ARCHITECTURE_ENABLED=false
IS_HERMES_ENABLED=true