UITableViewDropPlaceholder
A placeholder cell that supports customizing the drop preview parameters.
Declaration
@MainActor class UITableViewDropPlaceholderOverview
When you want to insert a placeholder cell into your table, create a UITableViewDropPlaceholder object and pass it to the drop(_:to:) method of your UITableViewDropCoordinator. You use a placeholder cell to display a temporary interface while you load the cell’s contents asynchronously. For example, your placeholder cell might display a progress indicator or a message that the cell content isn’t yet available. The placeholder object contains the reuse identifier of the temporary cell you want to display in your table. It can also include a custom preview to use during the drop.
You must register the cells you use with your placeholders in advance. In your storyboard file, add a table view cell object to your table, configure its appearance, set its class to UITableViewCell (or an appropriate subclass), and assign a reuse identifier to it. When you create your UITableViewDropPlaceholder object, pass the cell’s reuse identifier to init(insertionIndexPath:reuseIdentifier:rowHeight:). The table view uses the information in your placeholder object to insert the cell into the table.
Set the cellUpdateHandler to a block of code that configures the cell as a placeholder for the incoming data.
For more information, see Supporting drag and drop in table views.