Drag and Drop with Transferable (SwiftUI)

Two view modifiers give an app drag and drop: draggable marks a view as a drag source, and dropDestination marks a view as a drop target. Both move any type that conforms to Transferable, the same protocol behind ShareLink.

Dragging

Attach draggable with the value to move. Types such as URL conform to Transferable already, so no conversion code is needed. The trailing closure supplies the drag preview.

List {
    ForEach(links, id: \.self) { url in
        Text(url.absoluteString)
            .draggable(url) {
                Text(verbatim: url.absoluteString)
            }
    }
}

Any custom type works the same way once it conforms to Transferable. See the sharing-content doc in this area for the conformance recipe.

Dropping

dropDestination(for:) registers the area that accepts drops of one transferable type. The handler receives the decoded items and the drop location on screen.

List {
    ForEach(links, id: \.self) { url in
        Text(url.absoluteString)
            .draggable(url) { Text(verbatim: url.absoluteString) }
    }
    .dropDestination(for: URL.self) { items, location in
        links.append(contentsOf: items)
    }
}

The items parameter is an array because one drop can carry several values. The location parameter is the point where the user released the drag, useful for positioning inserted content.