'ContentView_Previews' is not a member type of error

Question

'ContentView_Previews' does not compile if ContentView references an external object.

If I remove all references to @ObservedObject, preview compiles.

import SwiftUI

struct ContentView: View {

    @ObservedObject var fancyTimer = FancyTimer()

    var body: some View {

    Text("\(fancyTimer.timerValue)")
       .font(.largeTitle)
    }
}

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

import Foundation
import SwiftUI
import Combine

class FancyTimer: ObservableObject {

    @Published var timerValue: Int = 0

    init() {

        Timer.scheduledTimer(withTimeInterval: 1.0, repeats: true) 
        { timer in
           self.timerValue += 1
        }
     }
   }

Error is: 'ContentView' is not a member type of 'FancyTimer'

Answer 1

Often the problem is that you created a class, a struct, or enum that has the same name as the module you are in.

Here, odds are that "FancyTimer" is also the name of your project, which triggers the error.

Try to change the class name.