SwiftUI: Automatic Preview Updating Error “Failed to build ContentView.swift”

Question

I\'m trying to run the Automatic Preview in Xcode 11, however even though the project builds successfully, the automatic preview fails giving me the error Failed to

Answer 1

First select the Xcode using following command

sudo xcode-select -s /Applications/Xcode.app/Contents/Developer

Then run

sudo xcodebuild -license

Hope it is helpful

Answer 2

I solved that problem by going to the Xcode - Preferences -> Locations and assigning the Command Line Tools to Xcode 11. Also keep in mind that it is a beta, so it is unstable.

Answer 3

I encountered this problem too. I download Xcode beta-1 before I download macOS 10.15. Then after my system upgrade to 10.15, the preview function didn't work. It turns out that Apple has released Xcode beta-2 version recently, so I downloaded and it worked. So, KEEP THE NEWEST VERSION OF XCODE!!!!

Answer 4

I had this problem as I was using // to comment beside my curly brackets to check I had them all in the right spot in my screen code. Xcode seems to cope with a few but once the screen gets too large and too many comments...... Now I comment on the line below and no problems!

Answer 5

I had this problem too. I solved it by moving the file location of the file I was trying to preview. When the file was created it was down below the resources folder, so I moved it up and then preview worked.