Object isn't updating in tableview with new Realm data - ios

Question

Whenever I click on a row in my tableview and change the text in the fields to something else, it always crashes and doesn't actually update the data. I'm saving all my data in a "Realm" database, which im fairly new at using.
I'm doing the updating in the "unwindToNoteList" function. Can someone help me know why it's adding a new row and crashing instead of updating the current row?
import UIKit
import Realm
class NoteTableViewController: UITableViewController {
// MARK: Properties
var notes = Note.allObjects()
override func viewDidLoad() {
super.viewDidLoad()
// Get Realm Database location
println(RLMRealm.defaultRealm().path)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// Return the number of sections.
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Return the number of rows in the section.
return Int(notes.count)
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
// Table view cells are reused and should be dequeued using a cell identifier.
let cellIdentifier = "NoteTableViewCell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! NoteTableViewCell
let object = notes[UInt(indexPath.row)] as! Note
// Configure the cell...
cell.titleLabel.text = object.title
cell.bodyLabel.text = object.body
return cell
}
// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return NO if you do not want the specified item to be editable.
return true
}
// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
// Delete from database
let realm = RLMRealm.defaultRealm()
realm.beginWriteTransaction()
realm.deleteObject(notes[UInt(indexPath.row)] as! RLMObject)
realm.commitWriteTransaction()
// Delete row from table view
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
} else if editingStyle == .Insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "ShowDetail" { // Clicked on a cell
let noteDetailViewController = segue.destinationViewController as! NoteViewController
// Get the cell that generated this segue.
if let selectedNoteCell = sender as? NoteTableViewCell {
let indexPath = tableView.indexPathForCell(selectedNoteCell)!
let selectedNote = notes[UInt(indexPath.row)] as! Note
noteDetailViewController.note = selectedNote
}
}
else if segue.identifier == "AddItem" { // Clicked add button
println("Adding new note")
}
}
#IBAction func unwindToNoteList(sender: UIStoryboardSegue) {
if let selectedIndexPath = tableView.indexPathForSelectedRow() { // User clicked on a row
// Update an existing note.
let realm = RLMRealm.defaultRealm()
realm.beginWriteTransaction()
Note.createOrUpdateInRealm(realm, withValue: ["title": note.title, "body": note.body, "id": note.id])
realm.commitWriteTransaction()
println("Yes")
tableView.reloadRowsAtIndexPaths([selectedIndexPath], withRowAnimation: .None)
}
else {
// Add a new note.
let newIndexPath = NSIndexPath(forRow: Int(notes.count), inSection: 0)
// Persist in database
let realm = RLMRealm.defaultRealm()
realm.beginWriteTransaction()
Note.createInRealm(realm, withValue: ["title": note.title, "body": note.body, "id": uuid])
realm.commitWriteTransaction()
println("no")
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Bottom)
}
}
}
}
Finally solved this, by not updating the object while in the tableview but while in the view controller that holds the text fields
Here's my NoteViewController
import UIKit
import Realm
class NoteViewController: UIViewController, UITextFieldDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {
// MARK: Properties
#IBOutlet var saveButton: UIBarButtonItem!
#IBOutlet var titleTextField: UITextField!
#IBOutlet var bodyTextField: UITextField!
/*
This value is either passed by `NoteTableViewController` in `prepareForSegue(_:sender:)`
or constructed as part of adding a new note.
*/
var note = Note?()
// MARK: Navigation
#IBAction func cancel(sender: UIBarButtonItem) {
// Depending on style of presentation (modal or push presentation), this view controller needs to be dismissed in two different ways.
let isPresentingInAddNoteMode = presentingViewController is UINavigationController
if isPresentingInAddNoteMode {
dismissViewControllerAnimated(true, completion: nil)
} else {
navigationController!.popViewControllerAnimated(true)
}
}
// This method lets you configure a view controller before it's presented.
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if saveButton === sender {
let title = titleTextField.text ?? ""
let body = bodyTextField.text ?? ""
/* The operator ?? unwraps the optional string in titleTextField.text since it may or may not have text in the field, and returns the value if it's a valid string. If nil though, it returns and empty string ("") instead
*/
// Update the database
let realm = RLMRealm.defaultRealm()
realm.beginWriteTransaction()
note?.title = titleTextField.text
note?.body = bodyTextField.text
realm.commitWriteTransaction()
// Set the note to be passed to NoteTableViewController after the unwind segue.
// AKA pass "note" to NoteTableViewController with whatever the text fields have in them
note = Note(title: title, body: body)
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
// Handle the text field’s user input through delegate callbacks.
titleTextField.delegate = self
// Set up views if editing an existing Note.
if let note = note {
navigationItem.title = note.title
titleTextField.text = note.title
bodyTextField.text = note.body
}
// Enable the Save button only if the text field has a valid Note name.
checkValidNoteName()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: UITextFieldDelegate
func textFieldDidBeginEditing(textField: UITextField) {
// Disable the Save button while editing.
saveButton.enabled = false
}
func checkValidNoteName() {
// Disable the Save button if the text field is empty.
let text = titleTextField.text ?? ""
saveButton.enabled = !text.isEmpty
}
func textFieldDidEndEditing(textField: UITextField) {
checkValidNoteName()
navigationItem.title = textField.text
}
}
And here's the original, NoteTableViewController. Updated a bit as well.
import UIKit
import Realm
class NoteTableViewController: UITableViewController {
// MARK: Properties
var notes = Note.allObjects()
override func viewDidLoad() {
super.viewDidLoad()
// Get Realm Database location
println(RLMRealm.defaultRealm().path)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: - Table view data source
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
// Return the number of sections.
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// Return the number of rows in the section.
return Int(notes.count)
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
// Table view cells are reused and should be dequeued using a cell identifier.
let cellIdentifier = "NoteTableViewCell"
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! NoteTableViewCell
let object = notes[UInt(indexPath.row)] as! Note
// Configure the cell...
cell.titleLabel.text = object.title
cell.bodyLabel.text = object.body
return cell
}
// Override to support conditional editing of the table view.
override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
// Return NO if you do not want the specified item to be editable.
return true
}
// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
// Delete from database
let realm = RLMRealm.defaultRealm()
realm.beginWriteTransaction()
realm.deleteObject(notes[UInt(indexPath.row)] as! RLMObject)
realm.commitWriteTransaction()
// Delete row from table view
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
} else if editingStyle == .Insert {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
}
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "ShowDetail" { // Clicked on a cell
let noteDetailViewController = segue.destinationViewController as! NoteViewController
// Get the cell that generated this segue.
if let selectedNoteCell = sender as? NoteTableViewCell {
let indexPath = tableView.indexPathForCell(selectedNoteCell)!
let selectedNote = notes[UInt(indexPath.row)] as! Note
noteDetailViewController.note = selectedNote
}
}
else if segue.identifier == "AddItem" { // Clicked add button
println("Adding new note")
}
}
#IBAction func unwindToNoteList(sender: UIStoryboardSegue) {
if let sourceViewController = sender.sourceViewController as? NoteViewController, note = sourceViewController.note {
let uuid = NSUUID().UUIDString // Needed for primary key. see below
var unwindedNote = Note()
if let selectedIndexPath = tableView.indexPathForSelectedRow() { // User clicked on a row
// Updating of the note is done in NoteViewController
tableView.reloadRowsAtIndexPaths([selectedIndexPath], withRowAnimation: .None)
}
else {
// Add a new note.
let newIndexPath = NSIndexPath(forRow: Int(notes.count), inSection: 0)
// Persist in database
let realm = RLMRealm.defaultRealm()
realm.beginWriteTransaction()
unwindedNote.title = note.title
unwindedNote.body = note.body
unwindedNote.id = uuid // This is done for the primary key that Realm needs, unique for each object created.
realm.addObjects([unwindedNote])
realm.commitWriteTransaction()
tableView.insertRowsAtIndexPaths([newIndexPath], withRowAnimation: .Bottom)
}
}
}
}

Answer 1

Looking at the code you provided there, I was going to suggest that putting your Realm writing logic in the view controller segue-controlled methods might be a little too late.
I would normally recommend that you should place any logic involving Realm writes in a method that is explicitly called from a user interacting with it. For example, in the tableView(_ tableView: UITableView,
didSelectRowAtIndexPath indexPath: NSIndexPath) method when they tap on a table cell, and then once the write has completed, perform the segue (or segue unwinding) then.
In any case, good to hear you solved it!