Open Radar

 
Summary:
Currently, the simulator will only execute one target from Xcode at once. It can run multiple apps at once, just like an actual device, but if you try to build and run from Xcode while another target is being debugged, you get an error that the simulator is already in use.

Every time I see that error message, I imagine a textfromxcode.com conversation and always think to myself “yeah, it’s being used by YOU.”

You can debug multiple targets on a device at once, it should work the same in the simulator.

This is especially important when working on WatchKit apps (and potentially other extensions). Each target can and will run together in the wild, and it is important to be able to debug the two together. Other cases where this comes in handy is when you have a client/server pair that need to communicate with each other at the same time.

But most importantly of all, it’s just down right annoying when you have to switch between different projects throughout the day. Which happens a lot when working on libraries from another project that you are working on as well.