如何通过按“添加”按钮添加新单元格并将文本保存到Coredata中

Question

I have a ViewController with tableview and a separate nib for create the table view cell,the cell contains a textview. press the add button,then the tableview will create a new cell,so i can input text into the textView. i want to insert cells to first row each time ,no matter how many cells existed. Finally ,press the done button to save the text to coredata.

the xib Entities name is "Checklist",the xib file name is "ChecklistCell"

class ChecklistViewController: 

    class ChecklistViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {

    var items = [Checklist]()

    var cellTextView:ChecklistCell!

    @IBOutlet weak var tableView: UITableView!

    @IBOutlet var toolBar: UIToolbar!

    let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext

    struct TableViewCellIdentifiers{
        static let checklistCell = "ChecklistCell"
    }

    @IBAction func addItem(){

       //i don't know how to write this code

    }

    @IBAction func toolBarDoneButton(_ sender: UIBarButtonItem) {
        //write data to coredata
        let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
        let item = Checklist(context: context)

        item.textView = cellTextView.textView.text

        (UIApplication.shared.delegate as! AppDelegate).saveContext()


    }
    override func viewDidLoad() {
        super.viewDidLoad()

        let cellNib = UINib(nibName: "ChecklistCell", bundle: nil)
        tableView.register(cellNib, forCellReuseIdentifier: "ChecklistCell")
    }

    override func viewWillAppear(_ animated: Bool) {
        getData()
        tableView.reloadData()
    }

    func getData(){
        do {
            items = try context.fetch(Checklist.fetchRequest())
        } catch {
            print("Fetching Failed")
        }
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: TableViewCellIdentifiers.checklistCell, for: indexPath) as! ChecklistCell

        let item = items[indexPath.row]

        if let myItem = item.textView {
            cell.textView.text = myItem
        }

        cell.textView.inputAccessoryView = toolBar

        return cell

    }



}

Answer 1

items = [Checklist()] + items will add a new Checklist object at the beginning (index [0] ) of your items array. If you were using a custom init method for your Checklist class, you would want to also fill in those init params here, like Checklist(/*init params here*/) .

To update your tableView for the user once you've altered its data source there is this answer: How to insert new cell into UITableView in Swift , which I have included in the below code.

For Swift 3.0 your addItem() function might look like:

func addItem() {

    items = [Checklist()] + items //adds Checklist item at beginning of array

    tableView.beginUpdates()
    tableView.insertRows(at: [IndexPath(row: 0, section: 0)], with: .automatic) //row param is 0 for first row
    tableView.endUpdates()
}

Hope that helps.