EnvironmentObject Error

App Development
1

Here I am again with an error I don’t understand. This relates to IOS Foundations, Mod4: Lesson 6.

The error (screenshot below) wants me to add an EnvironmentObject to the “appropriate preview”. The error results in the inability to preview the list view and the tab view. However, when I run the app on the simulator, I can navigate between views just fine, but the detail view only shows the recipe name and the other info is blank. Screenshots are below for each view’s code.

I have followed all Chris’ instructions for this mod, and the only view to which he did not add an instance of the EnvironmentObject was the detail view. So I added an instance there, but it made no difference. The error persists.

Any help would be greatly appreciated.

1Error Message
1Error Message1120×1012 83.4 KB

2Tab View
2Tab View1498×1174 209 KB

3Featured View
3Featured View1508×1324 179 KB

4ListView
4ListView1508×1324 290 KB

5DetailView top
5DetailView top1508×1324 329 KB

6DetailView bottom
6DetailView bottom1508×1324 237 KB

1 Like
3

As the error indicates, you need to add an environmentObject to your preview structs, not the main Views. Looks like it might be the RecipeListView that is causing the specific issue here.

And in the future, please post your code as text rather than screenshots. You can do this by placing three backticks ``` on the line before and three backticks ``` on the line after in order to nicely format the code. This makes it far easier to read and also makes it easier for other posters to copy/paste the code in order to test solutions and such.

4

Exactly where am I adding the environment object code. Could you be more specific?

I added the environment objects in the same places where Chris added them. This is what makes me so confused. Why did it work in his app, but not in mine when all the code is exactly the same?

Sorry about not including the the code in the message. Michelle always asks for a screen shot.

1 Like
5

You need it in the RecipeListView_Previews, like this:

struct RecipeListView_Previews: PreviewProvider {
    static var previews: some View {
        RecipeListView()
            .environmentObject(RecipeModel())
    }
}

The problem is the RecipeListView accesses a RecipeModel object injected into the environment in the RecipeTabView. But in the preview, there is nothing injecting this object so you have to add it.

2 Likes
6

Thanks so much. I still don’t understand why Chris didn’t need it there. However, I appreciate your help.

1 Like
7

The weird thing is that I downloaded the project files and got the same error there as well, How does Chris’s app compile successfully in the lesson?

8

Welcome to the community! I haven’t looked back at the lesson, let us check.

It’s very possible something changed. SwiftUI is brand new and things are constantly changing and breaking with every version update

9

Hello guys,

Thank you for the headsup @mikaelacaron, I will look for this issue today and will try to check what happened. I will try to give update later.

Thank you for bringing this up, @Diane53

1 Like
10

It’s a little unclear which Lesson this issue is related to. Let’s assume that this is Module 4 Lesson 6 as per the original post.

The project will compile and run successfully on a simulator. The fact that the Preview may not work does not stop the project from running on a simulator.

The project posted to DropBox for M4L6 does not have the modifier .environmentObject(RecipeModel()) attached to the Preview code for the RecipeListView. I suspect that this was likely an oversight when the project files were being assembled to be posted to Dropbox.

In fact it is not until M4L8 that the .environmentObject(RecipeModel())appears in the project files for the RecipeListView.

1 Like