拖放时出现错误“尝试将第 4 行插入第 1 节，但更新后第 1 节中只有 4 行”

Question

I'm trying to implement drop and drag, but getting an error: attempt to insert row 4 into section 1, but there are only 4 rows in section 1 after the update

I get this error, when try to drop item from Reminder to my tableView . I have this code im my ViewController:

extension ProfileViewController: UITableViewDropDelegate {
    func tableView(_ tableView: UITableView, performDropWith coordinator: UITableViewDropCoordinator) {
        let destinationIndexPath = IndexPath(row: tableView.numberOfRows(inSection: 1), section: 1)
        let item = coordinator.items[0]
        
        switch coordinator.proposal.operation {
        case .copy:
            print("Copying...")
            let itemProvider = item.dragItem.itemProvider
            
            itemProvider.loadObject(ofClass: NSString.self) { string, error  in
                if (string as? String) != nil {
                    let fasting = Fasting(autor: "Author", description: "Description", image: UIImage(named: "регби") ?? UIImage(), numberOfLikes: 0, numberOfviews: 0)
                    self.addGeocache(fasting, at: destinationIndexPath.row)
                    DispatchQueue.main.async {
                        tableView.insertRows(at: [destinationIndexPath], with: .automatic)
                    }
                }
        }
        default:
            return
        }
    }

Here I create numberOfRows im my tableView :

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        if section == 0 {
            return 1 
        } else {
            return Flow.sections.fasting.count
        }
    }

This is my array of elements in section 1:

struct Flow {
    
    static let sections = FastingSections(
            fasting: [
                Fasting(autor: "Gustav",
                        description: "Today i did eat this",
                        image: UIImage(named: "эко-мороженое 1")!,
                        numberOfLikes: 100,
                        numberOfviews: 100),
                Fasting(autor: "Dasha",
                        description: "I love this watch",
                        image: UIImage(named: "часы")!,
                        numberOfLikes: 200,
                        numberOfviews: 200),
                Fasting(autor: "Misha",
                        description: "Playing rugby with my friends",
                        image: UIImage(named: "регби")!,
                        numberOfLikes: 300,
                        numberOfviews: 300),
                Fasting(autor: "Nikita",
                        description: "Soon...",
                        image: UIImage(named: "cosmos")!,
                        numberOfLikes: 400,
                        numberOfviews: 400),
                    ]
                    )
}

Answer 1

Here

let fasting = Fasting(autor: "Author", description: "Description", image: UIImage(named: "регби") ?? UIImage(), numberOfLikes: 0, numberOfviews: 0)
self.addGeocache(fasting, at: destinationIndexPath.row)

It seems you add a new object to other data source other than Flow.sections.fasting hence the error while you need to change

static let sections = FastingSections(....

to

static var sections = FastingSections(....

and make any addition/deletion to it