Today I have started learning Flutter. I am using Android Studio in Mac. I have already
If iOS device not showing in an android studio then first open up simulator app in mac.
Open simulator app
after simulator is loaded, go to Hardware -> Device -> Manage Device and uncheck the physical device and go to simulator tab and choose the required simulator and check it 'Show as run destination' and reload android studio.
It will start showing in android studio and now you can run your flutter app in both android and iOS.
Manage Device