react-native-cross-button/example/Example/android/app/src/main/res/values/styles.xml

Integrate cross button, spinner, popOver(dropdown) and many other things.

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
    </style>

</resources>