I want to display an image (type UIImage) which is stored in an EnvironmentObject. This EnvironmentObject consists of an array of a structure which holds an UIImage element. In a view, I want to display an image of this array but this doesn't work somehow.

Here's the struct:

struct TestStruct: Identifiable {
    var id: String
    var name: String
    var image: UIImage

    init() {
        id = ""
        name = ""
        image = UIImage.init()
    }
}

Here the ModelData class:

final class ModelData: ObservableObject {
    @Published var testStruct: [TestStruct] = []
}

And this is the instantiation of modelData in the main app code:

struct TestApp: App {
    @ObservedObject private var modelData = ModelData()
    init() {...

The content of the modelData is loaded from a Firebase database and Firebase storage. This actually works, I can see the downloaded images in the modelData.testStruct[...].image in the debug preview.

From a view, I want to reference the image from the modelData:

struct StructContentView: View {
    @EnvironmentObject var modelData: ModelData

    var body: some View {
        ScrollView {
            Image(uiImage: modelData.testStruct[0].image)
                .frame(width: 64.0, height: 64.0)
                .foregroundColor(.red)           
        }
    }
}

Can someone help me? I'm generally confused with ObservableObject/EnvironmentObject and that stuff but I was able to display e.g. the field "name" of modelData.testStruct[0] in a TextView. Is the passing of the UIImage to the Image view wrong, maybe? Or something else needed there?

Thanks in advance for your support.

CodePudding user response：

In the getData completion callback of Firestone, it's set:

let reference = Storage.storage().reference(forURL: tempStruct.imageUrl)
                                reference.getData(maxSize: (1 * 1024 * 1024)) { (data, error) in
    if let _error = error{
      print(_error)
    } else {
      if let _data  = data {
        tempStruct.image = UIImage(data: _data)!
      }
    }
}

...

modelData.testStruct.append(tempStruct)

This is done when the App is started. The image will/shall then be later shown when the user goes to another menu item.

Solution:

The image of the testStruct type had to be changed to @Published, therefore it was also needed to change testStruct to a class:

class TestStruct: ObservableObject {
    var id: String
    var name: String
    @Published var image: UIImage

    init() {
        id = ""
        name = ""
        image = UIImage.init()
    }
}