Attach to running iOS application already running Xcode debugger

Is there a way to attach Android Studio/ IntelliJ to the running iOS application?

I have tried running the iOS application through Android Studio, and then trying to Xcode > Debug > Attach to process > Runner, and I got the error:

error: attach by pid '425' failed -- tried to attach to process already being debugged

This would be great as it would allow debugging the iOS and dart code simultaneously, like we can do for Android Applications (by attaching to the Android process in Android Studio).

[jmagman]

flutter run (same from the IDE) launches the app with lldb and stays connected. You can’t attach another lldb session through Xcode (that I’m aware of).
I would start the app from Xcode, then flutter attach as @stevemessick suggested.
If you need to launch the app through flutter instead of Xcode it’s more complicated–you would need to flutter run, detach (“d”), attach from Xcode, then flutter attach again.

[stevemessick]

Maybe @jmagman would have an idea about Xcode.

You might be able to launch your app from the command line, then try to attach both the Flutter debugger and Xcode debugger. I don’t know if that would work, but it may depend on the order of attachment. The Android Studio menu item is Run > Flutter Attach; it is also on the tool bar. Fair warning: Flutter Attach was designed to work for add-to-app projects; some people have reported success using it for regular apps, though. You might need to use additional arguments like flutter run --start-paused --machine. Some experimentation would be required. flutter help run lists all the arguments. The --start-paused arg is mostly used to ensure breakpoints are initialized before the app starts running. If you don’t need to debug initialization then you may be able to omit it. (It has been a while since I looked at the debugger code.)