SwiftUI - Unwrap optional image data to create Image based on UIImage(data)

Question

I have found this link and some answer says that we can solve two tasks:

• Display view element if needed
• Or display default value instead if nil found

I have data model which contain optional Data properly which I use for my Image element on the View.

Currently as I have not found a way how to workaround this and use this sign ! which is unsafe:

Image(uiImage: UIImage(data: userService.user.imageData!)!)

For sure I can't guarantee it and I should not use this, but need a help how to unwrap this.

As a quick workaround I can make this image data property as non optional and then load some data from the local file, but even then I still have one more force unwrapping here UIImage(data.

Answer 1

You have a few options available. I think the most straightforward is to make an extension on Image and define a new initialiser that will serve your needs:

extension Image {

    public init?(data: Data?) {
        guard let data = data,
            let uiImage = UIImage(data: data) else {
                return nil
        }
        self = Image(uiImage: uiImage)
    }
}

Then you can simply use it like this:

Image(data: userService.user.imageData)

since it is nullable it needs to be contained in another View with at least one other View.

If you want to provide a placeholder in place of a missing image you could use an extension like this:

extension Image {

    public init(data: Data?, placeholder: String) {
        guard let data = data,
          let uiImage = UIImage(data: data) else {
            self = Image(placeholder)
            return
        }
        self = Image(uiImage: uiImage)
    }
}

Then you can simply use it like this:

Image(data: userService.user.imageData, placeholder: "nameOfPlaceholder")

since it is not nullable it doe not need to be contained in another View with at least one other View.

Answer 2

Approach:

• Use control statements
• Use AnyView to erase type

Reason for AnyView

• You need to erase the type so that your view consistently returns the same view type irrespective which execution path it takes (whether if statement is satisfied or not).
• That way it returns AnyView no matter what and will satisfy the body type (some View)

Example:

• If the data is valid image data an image would be displayed
• If not then an empty view is displayed

Note: Instead of the empty view you could display any other view.

Code:

import SwiftUI

class Model : ObservableObject {
    var data : Data?

    init(data: Data?) {
        self.data = data
    }
}

struct ContentView: View {

    @ObservedObject var model : Model

    var body: some View {

        let view : AnyView

        if let data = model.data,
            let uiimage = UIImage(data: data) {
            view = AnyView(Image(uiImage: uiimage))
        }
        else {
            view = AnyView(EmptyView()) //You could have view = AnyView(Text("no image found"))
        }

        return view
    }
}