Swiftui - How do I initialize an observedObject using an environmentobject as a parameter?

Question

I'm not sure if this is an antipattern in this brave new SwiftUI world we live in, but essentially I have an @EnvironmentObject with some basic user information saved in it that my views can call.

I also have an @ObservedObject that owns some data required for this view.

When the view appears, I want to use that @EnvironmentObject to initialize the @ObservedObject:

struct MyCoolView: View { 

    @EnvironmentObject userData: UserData
    @ObservedObject var viewObject: ViewObject = ViewObject(id: self.userData.UID)  

    var body: some View { 
            Text("\(self.viewObject.myCoolProperty)")
    } 
}

Unfortunately I can't call self on the environment variable until after initialization:

"Cannot use instance member 'userData' within property initializer; property initializers run before 'self' is available."

I can see a few possible routes forward, but they all feel like hacks. How should I approach this?

Solution

Here is the approach (the simplest IMO):

struct MyCoolView: View {
    @EnvironmentObject var userData: UserData

    var body: some View {
        MyCoolInternalView(ViewObject(id: self.userData.UID))
    }
}

struct MyCoolInternalView: View {
    @EnvironmentObject var userData: UserData
    @ObservedObject var viewObject: ViewObject

    init(_ viewObject: ViewObject) {
        self.viewObject = viewObject
    }

    var body: some View {
            Text("\(self.viewObject.myCoolProperty)")
    }
}

Comments

[snarik]

This is perfect. The MyCoolView was actually a child to a 'home' view where I declared the ObservedObject. Thanks!

[BobiSad]

But what if you want to manipulate the userData inside ViewObject without an entirely new ViewObject being created every time?