How to install flutter and dart in Xcode macosx?

Dart and Flutter are officially supported by IntelliJ/Android Studio and VSCode.

I think there is some integration with VIM and Emacs, but not officially supported. There is no integration with XCode though.

You can install and use flutter on macOS. But you can not use XCode as IDE, officially they announced either use Android Studio / IntelliJ or Visual Studio Code.

For Android Studio / IntelliJ:

https://flutter.dev/docs/get-started/editor?tab=androidstudio

For Visual Studio Code:

https://flutter.dev/docs/get-started/editor?tab=vscode

As a suggestion iOS or other developer should use VSCode its light weighted and more understandable and android developer have their own option.