SwiftUI Canvas won't build

Question

I have some SwiftUI code and it seems to work great when I build to a real iOS device or to an iOS simulator.

However in the SwiftUI canvas the preview says Failed

Answer 1

Finally figured it out!

So it turns out, the reason it couldn't find the library was because I was referencing it with a relative path to a spot outside of my project directory.

My build settings had the Framework Search Paths set up like this:

../path/to/my/framework

And when I normally built my project this worked fine and it would find the framework. So it seems as though by default my build script is run from my project directory.

When I tried to build for SwiftUI, it must have been doing so from outside my root project directory so the relative framework path so no longer correct and I got the error shown in the question.

Updating the framework search path to a (slightly less relative?) path like this:

$(PROJECT_DIR)/../path/to/my/framework

made it so the framework could be found. Now I can successfully build the project and my SwiftUI canvas updates as it should.

Answer 2

So I had this same issue except it couldn't find my own module... For me the problem was because I have custom build configurations and it didn't like the custom module name. The solution was to rename the module to the same as debug and release in Build Settings > Product Module Name

I hope this helps someone