Example on how to use React Native as fragments in Android

BaseReactableActivity.class

public abstract class BaseReactableActivity extends BaseActivity {

    protected ReactInstanceManager mReactInstanceManager;

    private int OVERLAY_PERMISSION_REQ_CODE = 732;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && SystemConstants.IS_DEVELOPMENT) {
            if (!Settings.canDrawOverlays(this)) {
                Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION,
                        Uri.parse("package:" + getPackageName()));
                startActivityForResult(intent, OVERLAY_PERMISSION_REQ_CODE);
            }
        }

        mReactInstanceManager =
                ((MyApplication) getApplication()).getReactNativeHost().getReactInstanceManager();

    }

    @Override
    protected void onPause() {
        super.onPause();

        if (mReactInstanceManager != null) {
            mReactInstanceManager.onHostPause(this);
        }
    }

    @Override
    protected void onResume() {
        super.onResume();

        if (mReactInstanceManager != null) {
            mReactInstanceManager.onHostResume(this, this);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        if (mReactInstanceManager != null) {
            mReactInstanceManager.onHostDestroy(this);
        }
    }

    @Override
    public void onNewIntent(Intent intent) {
        super.onNewIntent(intent);
        mReactInstanceManager.onNewIntent(intent);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == OVERLAY_PERMISSION_REQ_CODE) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
                if (!Settings.canDrawOverlays(this)) {
                    // SYSTEM_ALERT_WINDOW permission not granted...
                }
            }
        }
        mReactInstanceManager.onActivityResult(this, requestCode, resultCode, data);
    }

    @Override
    public boolean onKeyUp(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_MENU && mReactInstanceManager != null) {
            mReactInstanceManager.showDevOptionsDialog();
            return true;
        }
        return super.onKeyUp(keyCode, event);
    }

    @Override
    public void onBackPressed() {
        if (mReactInstanceManager != null) {
            mReactInstanceManager.onBackPressed();
        } else {
            super.onBackPressed();
        }
    }
}

ExampleActivity.class

public class ExampleActivity extends BaseReactableActivity {

    private SectionAdapter mSectionsPagerAdapter;

    private ViewPager mViewPager;

    TabLayout tabLayout;
		
 		@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
      
				tabLayout = (TabLayout) findViewById(R.id.tabLayout);
			
				mSectionsPagerAdapter = new ProductsSectionAdapter(getSupportFragmentManager());
        mViewPager = (ViewPager) findViewById(R.id.container);
        mViewPager.setAdapter(mSectionsPagerAdapter);
        tabLayout.setupWithViewPager(mViewPager);

    }

    public class SectionAdapter extends FragmentPagerAdapter {

        public ProductsSectionAdapter(FragmentManager fm) {
            super(fm);
        }

        @Override
        public Fragment getItem(int position) {
            switch (position) {
                case 0:
                    return new ExampleFragment();
                case 1:
                    return new ExampleFragment2();
                default:
                    return null;
            }
        }

        @Override
        public int getCount() {
            return 2;
        }

    }
}

ExampleFragment.class

public class ExampleFragment extends ReactFragment {

    @Override
    public String getMainComponentName() {
        return "ExampleComponent";
    }
}

RectFragment.class

public abstract class ReactFragment extends Fragment {
    private ReactRootView mReactRootView;
    private ReactInstanceManager mReactInstanceManager;

    // This method returns the name of our top-level component to show
    public abstract String getMainComponentName();

    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        mReactRootView = new ReactRootView(context);
        mReactInstanceManager =
                ((MusilinxApplication) getActivity().getApplication())
                        .getReactNativeHost()
                        .getReactInstanceManager();

    }

    @Override
    public ReactRootView onCreateView(LayoutInflater inflater, ViewGroup group, Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        return mReactRootView;
    }


    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        mReactRootView.startReactApplication(
                mReactInstanceManager,
                getMainComponentName(),
                null
        );
    }
}