deleting object from realm database.

Question

I am writing Todo app. My app is simple. I have two pages. One page for showing tasks in table view. And one page for adding new tasks. In this page I post to server and then in main page I get data from server and then save it in realm database.

When I Want to delete them in my main page , my app crashes by this error.

  Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[TodoApp.TodosTableViewController delete:]: unrecognized selector sent to instance 0x7fca7b40b4c0

Anyone knows why? It is my deleting function :

public func delete<T:Object>(_ model: T) {
    let realm = try! Realm()
    
    try! realm.write {
        
        realm.delete(model)
        
        }
}

And this is the place that I use this function to delete from database :

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath){
        
        if editingStyle == UITableViewCellEditingStyle.delete {
            rowHere = indexPath.row
            // it crashes the app when I want to delete from database
            
//            delete(self.todos[self.rowHere!])
            
            self.todos.remove(at: indexPath.row)
            tableView.deleteRows(at: [indexPath as IndexPath], with:           UITableViewRowAnimation.automatic)
            
            
            
        }
    }

Answer 1

I implemented something similar in my app, hope it helps you.

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    //deleteRecords()
    delete(index: indexPath.row)
    retrieveFoods()
    tableView.reloadData()
}

func retrieveFoods() {
    let realm = try! Realm()
    myFoodsArray = realm.objects(MyFoods.self).sorted(byKeyPath: "name", ascending: true)
}

func delete(index: Int) {
    let myFood = myFoodsArray[index]
    let realm = try! Realm()
    try! realm.write {
        realm.delete(myFood)
        self.tableView.reloadData()
    }
}

Answer 2

First get Object model in viewDidLoad()

var DatabaseModel: Results<ObjectClassRealm>!

override func viewDidLoad() {
    super.viewDidLoad()
    let realm = RealmService.shared.realm
    DatabaseModel = realm.objects(ObjectClassRealm.self)
}


func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) { 
    guard editingStyle == .delete else { return }
    let objectData = DatabaseModel[indexPath.row]
    RealmService.shared.delete(objectData)
}

Or you can delete on button click

@IBAction func DeleteData(_ sender: Any) {
    let realm = try! Realm()
    let deleteData = realm.object(ofType: ObjectClassRealm.self, 
                                  forPrimaryKey: PRIMARYKEY)
    if deleteData == nil {
        print("No data in DB")
    } else {
        RealmService.shared.delete(deleteData!)
    }
}