iOS - How to insert a new To-Do item in a single view controller? - swift3

Question

I want to add a new To Do item when i press the add button,but i don't want to switch to another page.
press the add button to add a new row in the table view,input something and press the done button,it will save.
somebody suggests me to save the cells data to Model,but i don't know how to write this.
Who can help me?
import UIKit
import CoreData
class ToDoViewController: UIViewController {
var items: [NSManagedObject] = []
#IBOutlet weak var tableView: UITableView!
#IBAction func addItem(_ sender: UIBarButtonItem) {
//***How to write this code***
}
#IBAction func done(_ sender: UIBarButtonItem) {
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let entity = NSEntityDescription.entity(forEntityName: "ToDo", in: managedContext)!
let item = NSManagedObject(entity: entity, insertInto: managedContext)
//***let list = the current textView's text
//how to get the textView's text and assign it to a value.***
item.setValue(list, forKeyPath: "summary")
do {
try managedContext.save()
items.append(item)
} catch let error as NSError {
print("Could not save.\(error),\(error.userInfo)")
}
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(UITableViewCell.self,forCellReuseIdentifier: "Cell")
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
return
}
let managedContext = appDelegate.persistentContainer.viewContext
let fetchRequest = NSFetchRequest<NSManagedObject>(entityName: "ToDo")
do {
items = try managedContext.fetch(fetchRequest)
} catch let error as NSError {
print("Could not fetch.\(error),\(error.userInfo)")
}
}
}
extension ToDoViewController: UITableViewDataSource{
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let item = items[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
let textView = UITextView(frame: CGRect(x: 0, y: 0, width: cell.frame.size.width, height: cell.frame.size.height))
cell.addSubview(textView)
textView.text = item.value(forKey: "summary") as? String
return cell
}
}

Answer 1

Ok so If my understanding is right you need a new row to be added if they create a new entry into your Core Data. So in your viewWillAppear you're doing a fetch. What I think you need is a:
var fetchResultController : NSFetchedResultsController<YourType>!
Then using this fetch controller you want to do the following when fetching:
private func GetToDoEntries(){
if let appDele = UIApplication.shared.deletgate as? AppDelegate{
let givenContext = appDele.persistantContainer.viewContex
let entryFetchRequest : NSFetchRequest<YourType> = YourType.fetchRequest()
let sortDescriptors = NSSortDescriptor(key: "yourEntrySortKey" , ascending: true)
entryFetchRequest.sortDescriptors = [sortDescriptors]
fetchResultController = NSFetchedResultsController(fetchRequest: entryFetchRequest, managedObjectContext: givenContext, sectionNameKeyPath: nil, cacheName: nil)
fetchResultController.delegate = self
do{
//Gets fetched data based on our criteria
try fetchResultController.performFetch()
if let fetchedEntries = fetchResultController.fetchedObjects{
items = fetchedEntries as? WhateverToCastTo
}
}catch{
print("Error when trying to find entries")
}
}
}
First I'm sorry but I've just written this here is stackOverflow. So what you're doing is using a fetch result controller instead of a traditional search. You are required to have the sort descriptor as well and you can try to get the results and cast them to your items or as a NSManagedObject.
Now we're not done though. Your script needs to inherit from some behaviour. At the top of your class
class ToDoViewController : UIViewController, NSFetchedResultsControllerDelegate
You need the delegate as you can see in the first block of code because we're assigning it. Now we're almost there. You just need some methods to update the table for you and these come with the delegate we just inherited from.
//Allows the fetch controller to update
func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.beginUpdates()
}
//Allows new additions to be added to the table
func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
switch type{
case .insert:
if let _newIndexPath = newIndexPath{
tableView.insertRows(at: [_newIndexPath], with: .fade)
}
case .update:
if let index = indexPath{
tableView.reloadRows(at: [index], with: .fade)
}
default:
budgetEntryTable.reloadData()
}
if let fetchedObjects = controller.fetchedObjects{
items = fetchedObjects as! [NSManagedObject (Or your cast type)]
budgetEntryTable.reloadData()
}
}
//Ends the table adding
func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
tableView.endUpdates()
}
So there are 3 methods here. The first and second are very self explanatory. They begin and end the updates on your tableView. I'd also recommend that you change the name of your tableView to something other than "tableView" just for clarity.
The method in the middle uses a switch. My example is missing the "Move" and "Delete" options as I didn't required them in my project but you can add them to the switch statement.
The insert is checking the newIndexPath to see if there is one. If so then we add an array of the amount of rows required at the newIndexPath.
The update just checks the current index paths and then reloads the data on them incase you updated your data model.
I hope this is what you were looking for. Good luck! I'll try and help more if you need it but that should get you started.