No ObservableOblect

Question

Created Dec ’20

Replies 10

Boosts 0

Views 4.9k

Participants 4

Hi.
I'm studying SwiftUI, an error occurred when using .sheet in SwiftUI.
The code is:

Code Block import SwiftUI
class processStatus: ObservableObject {
  @Published var isRun: Bool = false
}
struct Home: View {
  @EnvironmentObject var startCollect: processStatus
   
  var body: some View {
    ZStack {
      HomeBackgound()
      VStack {
        Button(action:{
          self.startCollect.isRun.toggle()
        }) {
          VStack {
            Text("あつめる")
            Text("Collect")
          }
        }
        .frame(width: 250, height: 250)
      }
      .sheet(isPresented: self.$startCollect.isRun) { 
        SelectBall()
          .environmentObject(startCollect)
      }
    }
  }
}
struct Home_Previews: PreviewProvider {
  static var previews: some View {
    Home()
      .environmentObject(processStatus())
  }
}

The error is:

Code Block Thread 1: Fatal error: No ObservableObject of type processStatus found. A View.environmentObject(_:) for processStatus may be missing as an ancestor of this view.

on line 23.

Can anyone give me some advice?
Thanks.

Addendum: Added error details and error locations.

Boost

Answer 1

OOPer OP

Dec ’20

an error occurred

You should better include whole error message and the line of the error, to get better responses sooner.

0

Answer 2

OblivionMGD OP

Dec ’20

You should better include whole error message and the line of the error, to get better responses sooner.

Added error details and error locations. Sorry about that.

0

Answer 3

OOPer OP

Dec ’20

Added error details and error locations.

Thanks for adding the info.

But I cannot reproduce the error with your shown code.
You should better check other parts of your code using Home.

0

Answer 4

OblivionMGD OP

Dec ’20

The code for the other files can be found here.

When you press each button, the screen transitions in the order of "Home", "SelectBall", and "Processing".

0

Answer 5

OOPer OP

Dec ’20

The code for the other files can be found here.

No parts using Home can be found. You may need to check somewhere else.

0

Answer 6

OblivionMGD OP

Dec ’20

Home is only displayed in ContentView.swift. Here is the code.

Code Block import SwiftUI
import Neumorphic
struct ContentView: View {
    var body: some View {
        Home()
    }
}
struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Sorry if I can't provide the necessary files as I am a beginner. I would appreciate it if you could let me know if I have provided the wrong file.

0

Answer 7

BabyJ OP

Dec ’20

Home needs to be passed the EnvironmentObject.
In ContentView you could add

Code Block Swift@StateObject private var processStatus = processStatus()

and pass this into

Code Block SwiftHome()
	.environmentObject(processStatus()) // add this

0

Answer 8

OOPer OP

Dec ’20

Accepted Answer

Sorry if I can't provide the necessary files

You have no need to be sorry, in many cases, it is hard to choose necessary files, unless you know the solution.
It is very nice you have shown it by request.
Thanks for showing the code.

Seems your problem is that you are not passing an instance of EnvironmentObject using .environmentObject modifier.
(Doing such in preview, does not work for the actual app.)

When you use @EnvironmentObject in a view, you need to instantiate the object and pass it to the view (or a ancestor of the view) using .environmentObject, as found in your Home_Previews.

Please try adding .environmentObject into your ContentView:

Code Block struct ContentView: View {
    var body: some View {
        Home()
          .environmentObject(processStatus())
    }
}

In Swift, type names should start with Capital letter. Your processStatus looks a little bit odd.
(This is not critical, but you should better follow the most famous coding rule of Swift.)

2

Answer 9

OblivionMGD OP

Dec ’20

It worked fine. Thank you!

1

Answer 10

HossainEhsani OP

May ’21

As OOPer mentioned, the solution to the problem is to use .environmentObject(processStatus()) after calling a view. However, this solution only works when you are navigating from ContentView to other views using NavigationView. If you want to navigate to other views from your child views, and you use .environmentObject(processStatus()) for the target view, this method will not work, and the EnvironmentObject's properties will not be updated.

0