Goals
I'm trying to update a few records and delete them from NSTableView after that. http://take.ms/6r3IV
Expected Results
I expect that my records will be updated and NSTableView will be reloaded to reflect my changes.
Actual Results
My application crashes. http://take.ms/q6SWw
Steps to Reproduce
What are steps we can follow to reproduce this issue?
Code Sample
https://gist.github.com/msamoylov/27e1b6c9255b254f033f44d6de115d20
Version of Realm and Tooling
Realm version: 2.0.0 (installed as the Dynamic Framework)
Xcode version: 8.0 (8A218a)
macOS version: 10.12
It seems that I wasn't handling notifications properly. So, I ended up rewriting my code in this way:
import Cocoa
import RealmSwift
class ExerciseListViewController: NSViewController {
#IBOutlet weak var exerciseTableView: NSTableView!
let realm = try! Realm()
var exercises = try! Realm().objects(Exercise.self).filter("preferred = false").sorted(byProperty: "priority")
var notificationToken: NotificationToken? = nil
override func viewDidLoad() {
super.viewDidLoad()
exerciseTableView.dataSource = self
exerciseTableView.delegate = self
exerciseTableView.doubleAction = #selector(self.addPreferredExercises(_:))
notificationToken = exercises.addNotificationBlock { [weak self] (changes: RealmCollectionChange) in
guard let exerciseTableView = self?.exerciseTableView else { return }
switch changes {
case .initial:
exerciseTableView.reloadData()
break
case .update(_, let deletions, let insertions, _):
exerciseTableView.beginUpdates()
exerciseTableView.insertRows(at: IndexSet(insertions), withAnimation: .slideDown)
exerciseTableView.removeRows(at: IndexSet(deletions), withAnimation: .effectFade)
exerciseTableView.endUpdates()
if self?.exercises.count == 0 {
self?.dismiss(nil)
}
break
case .error(let error):
fatalError("\(error)")
break
}
}
}
deinit {
notificationToken?.stop()
}
#IBAction func addPreferredExercises(_ sender: AnyObject) {
if exerciseTableView.selectedRowIndexes.isEmpty {
let alert = NSAlert()
alert.messageText = "Hint"
alert.informativeText = "Please select at least one exercise from the list."
alert.alertStyle = .informational
alert.beginSheetModal(for: view.window!, completionHandler: nil)
}
try! realm.write {
for index in exerciseTableView.selectedRowIndexes {
if exercises.indices.contains(index) {
let exercise = exercises[index]
exercise.preferred = true
}
}
}
}
}
extension ExerciseListViewController: NSTableViewDataSource, NSTableViewDelegate {
func numberOfRows(in tableView: NSTableView) -> Int {
return exercises.count
}
func tableView(_ tableView: NSTableView, objectValueFor tableColumn: NSTableColumn?, row: Int) -> Any? {
return exercises.indices.contains(row) ? exercises[row].name : nil
}
func tableView(_ tableView: NSTableView, toolTipFor cell: NSCell, rect: NSRectPointer, tableColumn: NSTableColumn?, row: Int, mouseLocation: NSPoint) -> String {
let exercise = exercises[row]
let comment = exercise.comment as String!
return comment!
}
}
It still doesn't work 100% correct with multiple selections, but at least it's not crashing the app anymore. For some reason exerciseTableView.selectedRowIndexes contains non-existing indexes.
Related
I after asking another question today and fixed my Swift 4.2 code, I realized that I can't debug the app because of some profiles.
Errors shown when Testing application
The app also crashes on launch so there is not much I can do for now. I believe that the issue is how I am getting the information from the webserver (currently my computer). I am quite new to this, so i might have some mistakes in my code, so bear with me.
import UIKit
class InfoTableViewController: UITableViewController {
//MARK: Properties
class Produs {
var nume: String!
var codBare: String!
init(nume: String, codBare: String) {
self.nume = nume
self.codBare = codBare
}
}
var produse = [Produs]()
override func viewDidLoad() {
super.viewDidLoad()
//Load elements from server, theoretically
loadProducts()
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return produse.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// Table view cells are reused and should be dequeued using a cell identifier.
let cellIdentifier = "InfoTableViewCell"
guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? InfoTableViewCell else {
fatalError("The dequeued cell is not an instance of InfoTableViewCell.")
}
// Fetches the appropriate meal for the data source layout.
let produs = produse[indexPath.row]
cell.nameMain.text = produs.nume
cell.nameInfo.text = produs.codBare
return cell
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
// Get the new view controller using segue.destination.
// Pass the selected object to the new view controller.
}
//MARK: Private Methods
private func loadProducts() { //This function retrieves information in a JSON format from the server
var request = URLRequest(url: URL(string: "192.168.0.145")!)
request.httpMethod = "GET"
URLSession.shared.dataTask(with: request, completionHandler: { data, response, error -> Void in
do {
let decoder = JSONDecoder()
let json = try decoder.decode([[String]].self, from: data!)
print(json)
for produs in json {
print(produs)
var nume_prod: String = produs[0] // Numele produsului
var cod_ext: String = produs[1] // Codul de bare al produsului
var prod_obj = Produs(nume: nume_prod, codBare: cod_ext)
self.produse.append(prod_obj)
}
} catch {
print("JSON Serialization error")
}
}).resume()
}
}
I am getting the information from the server in a JSON file that is an array of arrays and looks like this:
[
[
"product1",
"code1"
],
[
"product2",
"code2"
],
[
"product3",
"code3"
]
]
Thank you for your help!
Don't send the JSON as array of arrays, send it as array of dictionaries. It simplifies the decoding considerably.
[
{"name":"product1", "code":"code1"},
{"name":"product2", "code":"code2"},
{"name":"product3", "code":"code3"}
]
Then declare the model as struct and never declare properties as implicit unwrapped optional which are initialized with non-optional values. If you need optionals declare them as regular optional (?) otherwise non-optional
struct Produs {
let name: String
let code: String
}
Replace loadProducts with
private func loadProducts() { //This function retrieves information in a JSON format from the server
let url = URL(string: "192.168.0.145")!
URLSession.shared.dataTask(with: url, completionHandler: {[unowned self] data, response, error in
if let error = error { print(error); return }
do {
self.produse = try JSONDecoder().decode([Produs].self, from: data!)
print(self.produse)
DispatchQueue.main.async {
self.tableView.reloadData()
}
} catch {
print(error)
}
}).resume()
}
And replace cellForRowAt with
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cellIdentifier = "InfoTableViewCell"
let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as! InfoTableViewCell
// Fetches the appropriate meal for the data source layout.
let produs = produse[indexPath.row]
cell.nameMain.text = produs.name
cell.nameInfo.text = produs.code
return cell
}
I have a NSTableView with 2 columns bound with a custom type (SelectedFiles) array as File Name and File Path, after clicking the header, I want it to sort the data in ascending / descending order, I tried these codes with NSSortDescriptor:
class ViewController: NSViewController, NSTableViewDataSource, NSTableViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
let fileNameSortDescriptor = NSSortDescriptor(key: "fileName", ascending: true, selector: #selector(NSString.localizedStandardCompare(_:)))
tableView.tableColumns[0].sortDescriptorPrototype = fileNameSortDescriptor
// other codes
}
}
extension ViewController: NSTableViewDataSource, NSTableViewDelegate {
func tableView(_ tableView: NSTableView, sortDescriptorsDidChange oldDescriptors: [NSSortDescriptor]) {
let selectedFilesArray = NSMutableArray(array: selectedFiles)
selectedFilesArray.sort(using: tableView.sortDescriptors) // Signal SIGABRT
selectedFiles = selectedFilesArray as! [SelectedFiles]
tableView.reloadData()
}
}
My custom collection for the data in table view:
struct SelectedFiles: CustomStringConvertible {
let fileName: String
let filePath: String
var description: String {
return "\(fileName) at path \(filePath)"
}
}
var selectedFiles: [SelectedFiles] = []
It turns out it doesn't work at all, IDK if its anything wrong with my code or I'm missing something.
So, I came up with this awkward solution:
var tableViewSortingOrder = ComparisonResult.orderedAscending
extension ViewController: NSTableViewDataSource, NSTableViewDelegate {
func tableView(_ tableView: NSTableView, sortDescriptorsDidChange oldDescriptors: [NSSortDescriptor]) {
switch tableViewSortingOrder {
case .orderedAscending:
tableViewSortingOrder = .orderedDescending
selectedFiles.sort { (previous, next) -> Bool in
return previous.fileName.compare(next.fileName) == tableViewSortingOrder
}
default:
tableViewSortingOrder = .orderedAscending
selectedFiles.sort { (previous, next) -> Bool in
return previous.fileName.compare(next.fileName) == tableViewSortingOrder
}
tableView.reloadData()
}
}
After I changed to this solution, it worked perfectly as it switches swiftly between ascending / descending order. But, when it comes to deleting objects in the collection, it throws Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value when I'm trying to delete multiple objects from both collection and table view with some specific files.
So, I'm thinking if I should change a way of achieving this header sorting thing by using NSSortDescriptor (use the old-fashioned way by correcting my first method) in order to get away from this issue, I have to admit that my second way is a bit of awkward (is more like a plan C).
I've red through multiple StackOverflow posts on this topic and I tried all of their ways, especially this one, I am not using CoreData which its solutions does not work for my situation.
Anyone can help point out the way please? 😊
I red the guide to NSTableView from Apple Developer Site and few other StackOverflow posts, I found myself a workable solution for Swift 4:
I set the sortDescriptorPrototype to fileNameSortDescriptor in viewDidLoad() under ViewController class.
class ViewController: NSViewController {
override func viewDidLoad()
super.viewDidLoad()
let fileNameSortDescriptor = NSSortDescriptor(key: "fileName", ascending: true, selector: #selector(NSString.localizedStandardCompare))
let tableColumn = tableView.tableColumn(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "fileNameColumn"))!
tableColumn.sortDescriptorPrototype = fileNameSortDescriptor
// other codes
}
}
And then I added an inheritance from NSObject and inserted #objcMembers to prevent warning: Object <#object#> of class '<#class#>' does not implement methodSignatureForSelector: -- trouble ahead from occurring and then cause Signal SIGABRT while calling selectedFiles.sort(using: tableView.sortDescriptors) (Reference: Object X of class Y does not implement methodSignatureForSelector in Swift).
#objcMembers class SelectedFiles: NSObject {
let fileName: String
let filePath: String
override var description: String {
return "\(fileName) at path \(filePath)"
init(fileName: String, filePath: String) {
self.fileName = fileName
self.filePath = filePath
}
}
Here's the code for tableView(_:sortDescriptorsDidChange:) in NSTableViewDataSource:
extension ViewController: NSTableViewDataSource {
func tableView(_ tableView: NSTableView, sortDescriptorsDidChange oldDescriptors: [NSSortDescriptor]) {
var selectedFilesArray = NSArray(array: selectedFiles)
selectedFilesArray = selectedFilesArray.sortedArray(using: tableView.sortDescriptors) as NSArray
selectedFiles = selectedFilesArray as! [SelectedFiles]
tableView.reloadData()
}
}
Now, everything works perfectly fine.
I'm apparently designing a drag and drop dropbox which can either select files by clicking it or dragging and dropping the files on it, and I want the selected files to be visible in a table next to it. My design logic is that whenever the user selects files from an NSOpenPanel, it passes the selected file paths into the CoreData and then an array retrieves them one by one from the CoreData, and finally, update the NSTableView's content by using reloadData().
Basically, my problem is that whenever I try to call ViewController().getDroppedFiles() from DropboxButton class, I always get a Fatal error: unexpectedly found nil while unwrapping an optional value.
My ViewController.swift:
import Cocoa
class ViewController: NSViewController, NSTableViewDataSource, NSTableViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
getDroppedFiles()
}
#IBOutlet weak var DroppedFilesTableView: NSTableView!
var droppedFiles: [DroppedFiles] = [] // Core Data class definition: DroppedFiles
func numberOfRows(in tableView: NSTableView) -> Int {
return droppedFiles.count
}
func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
let droppedFilesCollection = droppedFiles[row]
if (tableView?.identifier)!.rawValue == "fileNameColumn" {
if let fileNameCell = tableView.makeView(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "fileNameCell")) as? NSTableCellView {
fileNameCell.textField?.stringValue = droppedFilesCollection.fileName!
return fileNameCell
}
} else if (tableView?.identifier)!.rawValue == "filePathColumn" {
if let filePathCell = tableView.makeView(withIdentifier: NSUserInterfaceItemIdentifier(rawValue: "filePathCell")) as? NSTableCellView {
filePathCell.textField?.stringValue = droppedFilesCollection.filePath!
return filePathCell
}
}
return nil
}
#IBAction func DropboxClicked(_ sender: NSButton) {
// selected file paths
for filePath in selectedFilePaths {
if let context = (NSApp.delegate as? AppDelegate)?.persistentContainer.viewContext {
let droppedFilesData = DroppedFiles(context: context)
droppedFilesData.fileName = getFileName(withPath: filePath)
droppedFilesData.filePath = filePath
do {
try context.save()
} catch {
print("Unable to save core data.")
}
}
getDroppedFiles()
}
}
func getDroppedFiles() {
if let context = (NSApp.delegate as? AppDelegate)?.persistentContainer.viewContext {
do {
try droppedFiles = context.fetch(DroppedFiles.fetchRequest())
} catch {
print("Unable to fetch core data.")
}
}
DroppedFilesTableView.reloadData() // Fatal Error: unexpectedly found nil while unwrapping an optional value (whenever I call this function in other class)
}
}
I'm using a push button (NSButton) as the dropbox (it has its own class), which can easily be clicked and also supports dragging options.
My DropboxButton.swift:
import Cocoa
class DropboxButton: NSButton {
required init?(coder: NSCoder) {
super.init(coder: coder)
registerForDraggedTypes([NSPasteboard.PasteboardType.URL, NSPasteboard.PasteboardType.fileURL])
}
override func draggingEntered(_ sender: NSDraggingInfo) -> NSDragOperation {
// some other codes
return .copy
}
override func draggingExited(_ sender: NSDraggingInfo?) {
// some other codes
}
override func draggingEnded(_ sender: NSDraggingInfo) {
// some other codes
}
override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
guard let pasteboard = sender.draggingPasteboard.propertyList(forType: NSPasteboard.PasteboardType(rawValue: "NSFilenamesPboardType")) as? NSArray,
let filePaths = pasteboard as? [String] else {
return false
}
for filePath in filePaths {
if let context = (NSApp.delegate as? AppDelegate)?.persistentContainer.viewContext {
let droppedFilesData = DroppedFiles(context: context)
droppedFilesData.fileName = getFileName(withPath: filePath)
droppedFilesData.filePath = filePath
do {
try context.save()
} catch {
print("Unable to save core data.")
}
}
ViewController().getDroppedFiles() // found nil with reloadData() in ViewController.swift
}
return true
}
}
And this is my interface and code logic:
So, how can I reloadData() for the table view in my ViewController class from another class (DropboxButton: NSButton) so that whenever the user drags and drops files into the dropbox, the table view will reload?
P.S. To get this done means a lot to me, I really need to get this fixed in a short time, is there anyone can spend some time and help me?
You need to call getDroppedFiles() on a loaded instance of ViewController.
With ViewController().getDroppedFiles() you're creating a new instance of ViewController that is not shown anywhere (so controls are not initialized resulting in the nil error).
I found this solution useful for my case.
I used observer to pass through data and call functions from other controller classes, now I understand that I was creating a new instance of ViewController which is not loaded. Here is my code:
ViewController.swift:
class ViewController: NSViewController {
// other codes
override func viewDidLoad() {
super.viewDidLoad()
NotificationCenter.default.addObserver(self, selector: #selector(getDroppedFiles), name: NSNotification.Name(rawValue: "reloadTableViewData"), object: nil)
}
#objc func getDroppedFiles() {
DroppedFilesTableView.reloadData()
}
}
DropboxButton.swift:
class DropboxButton: NSButton {
// other codes
override func performDragOperation(_ sender: NSDraggingInfo) -> Bool {
// other codes
NotificationCenter.default.post(name: NSNotification.Name(rawValue: "reloadTableViewData"), object: nil)
return true
}
}
And now, everything works perfectly, I can even add an userInfo: to pass data between files and classes.
When a cell is deleted, the item at the end of the list takes the place of the item that just got deleted. This only happens when there are more than 3 items in the list.
In the gif below I delete numbers 3 and 4 which leaves me with numbers 1,2,5 in the simulator. HOWEVER in the Realm file I have numbers 1,2,4. I have no clue why it does this?
Data Model
import Foundation
import RealmSwift
class Item: Object {
#objc dynamic var name = ""
}
View Controller
import UIKit
import RealmSwift
class ListViewController: UITableViewController {
let realm = try! Realm()
var itemArray : Results<Item>?
var item:Item?
override func viewDidLoad() {
super.viewDidLoad()
self.itemArray = realm.objects(Item.self)
}
#IBAction func addButtonPressed(_ sender: UIBarButtonItem) {
var textField = UITextField()
let alert = UIAlertController(title: "Add New Item", message: "", preferredStyle: .alert)
alert.view.tintColor = UIColor.red
let action = UIAlertAction(title: "Add Item", style: .default) { (action) in
let newItem = Item()
newItem.name = textField.text!
try! self.realm.write {
self.realm.add(newItem)
}
self.tableView.reloadData()
}
alert.addTextField { (alertTextField) in
alertTextField.placeholder = "Create new item"
textField = alertTextField
}
alert.addAction(action)
present(alert, animated: true, completion: nil)
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.itemArray!.count//Size of the Array
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ItemCell", for: indexPath)//Asigns the Protocol Cell
let data = self.itemArray![indexPath.row]
cell.textLabel?.text = data.name
return cell
}
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
if let item = itemArray?[indexPath.row] {
try! self.realm.write {
self.realm.delete(item)
}
tableView.deleteRows(at: [indexPath], with: .automatic)
}
}
}
You are retrieving an unsorted result set from Realm, which as per documentation does not necessarily retain insertion order after deletions (basically when you remove 3, then 5 is shifted in its place):
Note that the order of Results is only guaranteed to stay consistent when the query is sorted. For performance reasons, insertion order is not guaranteed to be preserved.
So there are two things you can do:
1.) sort the result set
2.) instead of assuming you're only deleting a single object and otherwise have no movements of any sort, you can rely on Realm's own diffing + change set evaluation with a notification token so that you receive a change set for any possible change that happens to the result set.
// see https://realm.io/docs/swift/latest/#collection-notifications
class ViewController: UITableViewController {
var notificationToken: NotificationToken? = nil
override func viewDidLoad() {
super.viewDidLoad()
let realm = try! Realm()
let results = realm.objects(Person.self).filter("age > 5")
// Observe Results Notifications
notificationToken = results.observe { [weak self] (changes: RealmCollectionChange) in
guard let tableView = self?.tableView else { return }
switch changes {
case .initial:
// Results are now populated and can be accessed without blocking the UI
tableView.reloadData()
case .update(_, let deletions, let insertions, let modifications):
// Query results have changed, so apply them to the UITableView
tableView.beginUpdates()
tableView.insertRows(at: insertions.map({ IndexPath(row: $0, section: 0) }),
with: .automatic)
tableView.deleteRows(at: deletions.map({ IndexPath(row: $0, section: 0)}),
with: .automatic)
tableView.reloadRows(at: modifications.map({ IndexPath(row: $0, section: 0) }),
with: .automatic)
tableView.endUpdates()
case .error(let error):
// An error occurred while opening the Realm file on the background worker thread
fatalError("\(error)")
}
}
}
deinit {
notificationToken?.invalidate()
}
}
I am using cell-based tableview to store custom class data, for example
class Person {
var name:String = ""
var age: Int = 0
}
And then use a NSMUtableArray to collect person1, person2 ... datas, call it dataArray.
Present Person name on column1 and age on column2, works fine and editable.
func tableView(_ tableView: NSTableView, objectValueFor tableColumn: NSTableColumn?, row: Int) -> Any? {
if tableColumn?.identifier == "Name"
{
return (self.dataArray[row] as! Person).name
}
else if tableColumn?.identifier == "Age"
{
return (self.dataArray[row] as! Person).age
}
}
How can I sort each column with respected sortDescriptor?
I follow that fefernce but "sortDescriptorWithKey:tableColumn.identifier" always fail in my code, it can be passed if set the tableColumn.identifier to "self", it also confused me.
Below are my other code fragments.
func tableView(_ tableView: NSTableView, sortDescriptorsDidChange oldDescriptors: [NSSortDescriptor]) {
let newDescriptors = tableView.sortDescriptors
dataArray.sort(using: newDescriptors)
tableView.reloadData()
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
// Sort
for tableColumn in tableView.tableColumns {
let sortDescrptor = NSSortDescriptor.init(key: tableColumn.identifier, ascending: true, selector: #selector(NSString.caseInsensitiveCompare))
tableColumn.sortDescriptorPrototype = sortDescrptor
}
}