Is it necessary to install Android Studio for flutter or what can be replacement for android studio?

You need to install Android Studio in order to get Android SDK. After you use Android Studio to get the Android SDK, you can continue use VScode for flutter development.

Hope this answer helps!

You are going to need the Android SDK to be able to develop Android apps. If you don't want to install Android Studio, then you have to use the command line tools. https://developer.android.com/studio#downloads

If you are comfortable using the command line then you can do that. https://developer.android.com/studio/command-line

You don't specifically need Android Studio, all you need is the Android SDK, download it and set the environment variable to the SDK path for the flutter installation to recognise that.

You can refer this medium article: https://medium.com/@sadabwasim/flutter-in-linux-37d32890745b