Do we require backend also for Android development as in websites??

Question

As we know we have various frameworks for Android development.. such as flutter, reactnative and so on. So do they support backend it self or we need to learn some other backend languages

Answer 1

Yes those are just frontEnd framework just to make user interface and fetch data.
For React Native we do use NodeJS and express and other backend languages can also be used..

Answer 2

even there is the Spring for Android
https://spring.io/projects/spring-android