ios - ionic3 - Apple Mach -O Linker (Id) Error?

Question

This is the all error showing:

Apple Mach -O Linker (Id) Error? 
"Linker command failed with exit code 1 (use -v to see invocation). 

After I install OneSignal plugin in my ionic3 project, haven't setup all , When I tried to run my project in my device, this error coming out.

And when I open .xcworkspace file, two project showing to me. First one is my real project, last one is after I install OneSignal plugin and install sudo gem install cocoapods, pod repo update then showing

Just now I tried run ionic cordova run ios --device that can run in my device, but when I use xcode and hit play button which cannot run in my device and showing the error that my question title

Answer 1

Finally I found the way to solve this error!

Because I install pod for push notification fucntion, so try to use the .xcworkspace file to run the project after pod install instead of .xcodeproj file.

But I still don't know why .xcworkspace will showing this error when I install pod, if you know comment here please, thanks a lot!