Reputation: 1395

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

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

Cannot preview in this file - active scheme does not build this file

Try Again, Diagonistics option or restarting Xcode not solving the problem.

Upvotes: 45

Answers (22)

kev

Reputation: 71

For the sake of helping someone else out that make the mistake I did. I accidentally deleted the 'Compile Sources' in the 'Build Phases' of my project's Target. I then had to re-add all the files that needed compiling in the scheme to get the preview working again. Click on the "+" in the top left and choose 'New Compile Sources Phase', then in the new section created , tap that "+" and choose all the files in your project that need compiling.

Upvotes: 2

Hutomo Sakti Kartiko

Reputation: 31

Restarting the Xcode work for me.

My case: Clone and running swiftUI project in another device.

Upvotes: 0

schornon

Reputation: 382

There are 9k reasons of this error. My case: I'm developing Swift Package. When I added Example folder to this Package and put Demo project inside - My Xcode Canvas (#Preview {}) displayed error above. So, I solved it by closing Xcode window with my Swift Package.

Upvotes: 0

Code on the Rocks

Reputation: 17596

I ran into this error when the path to my Swift project contained hyphens (ex. ~/Dev/VisionOS-tips-and-tricks/Day001).

Changing the folder name to something without hyphens seemed to fix the issue (ex. ~/Dev/VisionOSTips/Day001).

Upvotes: 1

Zhou Haibo

Reputation: 2068

For me, I go to system settings -> storage -> Developer -> delete "Project Build data and indexes" to fix this problem.

Upvotes: 0

nyxee

Reputation: 2811

I just changed my preview code from this format:

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

To this format:

#Preview {
    ContentView()
}

Everything else failed.

Upvotes: 0

Bill Chan

Reputation: 3455

In my case I cleaned the derivedDate folder and restart Xcode solves the issue.

Update 2023: I reopen the project with Xcode 14.3 and the issue is solved.

Upvotes: 1

puma-lima

Reputation: 17

Another solution:

Make sure you select file type Swift UI instead of Swift File when you create the file.

Upvotes: -1

FBB

Reputation: 344

Make sure the file you are trying to preview is in your app (the folder with the same name as your project).

I was able to fix newly created files not previewing by moving the file into my project.

Upvotes: 1

Bravman

Reputation: 1

Try About this mac -> Storage -> Manage -> Developer, Then delete Xcode cache from here then restart Xcode...This worked out for me

Upvotes: 0

Robert Hartman

Reputation: 105

I found that the file I was trying to preview was not listed in Target -> Build Phases -> Compile Sources. Once I manually added the file, Preview worked. I had drag and dropped a directory into the project, and for some reason Xcode had not added those files to that list.

Upvotes: 0

Jack

Reputation: 2344

I just upgraded to both Monterey 12.3, and Xcode 13.3, and boom ran into this issue. Things were fine before the upgrade. Nothing above helped.

Creating a new project does help. So the only thing I found is to create a new project, and just add the files from the old project to the new one. Yuk.

EDIT: I hadn't rebooted the computer (mac mini), after reboot things were fine again.

Upvotes: 1

ubuntudroid

Reputation: 3999

The described issue happened to me after cloning a project via git (no iCloud syncing as described in another answer - so I definitely know that the sync itself was completely done).

Funny enough restarting Xcode did the trick.

Just closing and opening the project isn't enough.

Upvotes: 2

Eray Hamurlu

Reputation: 783

Restarting my PC worked for me.

Upvotes: 0

Keivan

Reputation: 1781

You should go through Xcode and Apple SDKs Agreement and you can do it by running the following in terminal in mac:

sudo xcodebuild -license

After doing that reopen your project.

Upvotes: 30

Shane

Reputation: 1075

I bumped into this too, following the Landmarks tutorial. When I created the 'CircleImage.swift' it was not letting me preview it, with the above error message.

You can see the current Scheme you're using by going to Product > Scheme. I've got macOS selected.

Clicking on the CircleImage.swift file loads it, and in the rightmost sidebar it shows the Attributes inspector. A few buttons to the left of that is "Show the File inspector".

There, you can see this file's chosen "Target Membership". My problem was that "Landmarks (macOS)" was not checked. Checking this immediately got the Preview working.

I imagine I could also have changed my Product's Scheme to iOS and it would have worked, as that was already checked.

Upvotes: 5

Wayne Ohm

Reputation: 71

This problem happened to me when I copied a folder into my project with the "Create folder reference" option instead of the "Create groups" option. The problem was solved when I deleted the folder from project and copied the folder again with the latter option.

Upvotes: 5

Xinyi Xiang

Reputation: 1

In the schemes I was able to select, it contained only one scheme. Reopening the folder in a folder that's not in the Downloads directory made live editing work for me

Upvotes: 0

Alain ANDRE

Reputation: 539

If this is a new project coming from a copied folder and inside an iCloud folder, just close Xcode and relaunch it. The sync was not yet done.

Upvotes: 43

JasonY

Reputation: 474

I encountered the same error for some of my SwiftUI View files when trying to preview on Canvas. What fixed the issue was I copied the code within the current file, deleted the file, created a new SwiftUI View file under the same name and pasted the original code. Hope that helps!

Creating a new folder in Documents/Desktop and copying the files over also resolves the issue.

Upvotes: 4