Cannot preview in this file - active scheme does not build this file : SwiftUI on Xcode 11 in CatalinaOS

Question

I opened Landmark App using SwiftUI on Xcode 11 in macOS Catalina(10.15) and while opening the Canvas Editor for .swift files containing SwiftUI is showing

Answer 1

I experienced the same issue. All I did was to copy the "StartingPoint" folder out of the downloaded folder and relaunched the project. It worked!!!