React Native : Going fullscreen on Android

styles.xml:

in android/app/src/main/res/values/styles.xml configure like following:

<resources>

<style name="Theme.AppCompat.Light.NoActionBar.FullScreen" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowActionBar">false</item>
    <item name="android:windowFullscreen">true</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:navigationBarColor">#000000</item>
</style>
</resources>

AndroidManifest.xml:

in android/app/src/main/AndroidManifest.xml configure like following:

<application
      android:name=".MainApplication"
      android:label="@string/app_name"
      android:icon="@mipmap/ic_launcher"
      android:roundIcon="@mipmap/ic_launcher_round"
      android:allowBackup="false"
      android:theme="@style/Theme.AppCompat.Light.NoActionBar.FullScreen">
      <activity
     <!-- ... -->
      </activity>
     <activity
     <!-- ... -->
      </activity>
     <!-- ... -->
    </application>

Hiding Navigation Bar:

For making navigation go away completely simply put navigation bar into immersive sticky mode by putting MainActivity.java. In android/app/src/main/java/com/company/MainActivity.java like following:

//...
import android.os.Bundle;
import android.view.View;
import android.content.res.Configuration;

public class MainActivity extends ReactActivity {

//    ...

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

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);
        if (hasFocus) {
            hideNavigationBar();
        }
    }

    private void hideNavigationBar() {
        getWindow().getDecorView().setSystemUiVisibility(
            View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);

    }

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

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        hideNavigationBar();
    }
    
}

Now navigation bar can only be accessed by tapping near at only the edge of screen.
References:
https://facebook.github.io/react-native/docs/statusbar.html
https://developer.android.com/jetpack/androidx/releases/appcompat