so first i made a custom object :
import Foundation
class Website {
var name:String
var pictureLabel:String
init(title:String,pictureLabel:String) {
name = title
pictureLabel = picture
}
}
and then on my tableviewcontroller class :
class ViewController:
UIViewController,UITableViewDelegate,UITableViewDataSource {
var websites = [Website]()
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
tableView.rowHeight = 80
tableView.register(MyCell.self, forCellReuseIdentifier: "MyCell")
websites.append(Website(title: "facebook.com", pictureLabel: "facelogo"))
print(websites)
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return websites.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MyCell", for: indexPath) as! MyCell
cell.label.text = websites[indexPath.row].name
return cell }
error : Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value: file
the problem was on that line
tableView.register(MyCell.self, forCellReuseIdentifier: "MyCell")
it should be
tableView.register(UINib(nibName: "MyCell", bundle: nil), forCellReuseIdentifier: "MyCell")`
Related
when I tried to use this code to get the images, I'm not getting list list of images
import UIKit
class ViewController: UITableViewController {
var pictures = [String]()
override func viewDidLoad() {
super.viewDidLoad()
let fm = FileManager.default
let path = Bundle.main.resourcePath!
let items = try! fm.contentsOfDirectory(atPath: path)
for item in items {
if item.hasPrefix("nssl"){
//load pics
pictures.append(item)
}
}
print(pictures)
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return pictures.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Picture", for: indexPath)
cell.textLabel?.text = pictures[indexPath.row]
return cell
}
}
I have an empty array set as a global variable that is populated with array items from a tableview. This is used to populate another tableview. This data needs to persist so that when the user returns to the app, their tableview data is in the same state they left it, i.e. populate with data from the array.
Though I've looked for dozens of tutorials and examples. I've also hacked at it myself to make it work and every time I reload the app, the array is empty. How can I get that global variable array to hold onto it's array data?
var sharedData = [String]()
This is my 1st VC where I have setup functions for the UserDefaults. And I've executed my saveArray() func every time a change is made to the array. I've then executed retrieveArray() func every time I need to load from the array.
import UIKit
var sharedData = [String]()
struct Keys {
static let arrayKey = "arrayKey"
}
let defaults = UserDefaults.standard
func saveArray() {
defaults.set(sharedData, forKey: Keys.arrayKey)
}
func retrieveArray() {
var savedData = defaults.object(forKey: Keys.arrayKey) as? [String] ?? []
savedData.append(contentsOf: sharedData)
}
class ViewController: UIViewController {
var effect:UIVisualEffect!
#IBOutlet weak var searchBar: UISearchBar!
#IBOutlet var tableView: UITableView!
#IBOutlet weak var activityIndicator: UIActivityIndicatorView!
#IBOutlet weak var visualEffectView: UIVisualEffectView!
let materialData = ["One", "Two", "Three", "Four"]
var searchMaterial = [String]()
var searching = false
#IBAction func favoritesButtonArrayUpdate(_ sender: UIBarButtonItem) {
print(sharedData)
}
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
saveArray()
retrieveArray()
print(sharedData)
}
extension ViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
print(self.materialData[indexPath.row], "selected!")
}
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let favorite = UITableViewRowAction(style: .default, title: "Favorite") { (action, indexPath) in
var data: String
if self.searching {
data = self.searchMaterial[indexPath.row]
} else {
data = self.materialData[indexPath.row]
}
sharedData.append(data)
saveArray()
print(sharedData)
}
favorite.backgroundColor = UIColor.orange
return [favorite]
}
}
This is my 2nd VC which displays the array data stored in the global variable array sharedData. I've again added all the func when making changes to the array and pulling data from the array.
import UIKit
class FavoritesViewController: UIViewController {
#IBOutlet var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
saveArray()
retrieveArray()
}
}
extension FavoritesViewController: UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
retrieveArray()
return sharedData.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
retrieveArray()
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.numberOfLines = 0
cell.textLabel?.text = sharedData[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
sharedData.remove(at: indexPath.row)
saveArray()
tableView.beginUpdates()
tableView.deleteRows(at: [indexPath], with: .automatic)
tableView.endUpdates()
}
}
}
The problem could be here:
let savedData: [String] = userDefaults.object(forKey: "arrayKey") as? [String] ?? []
Try changing it with:
let savedData: [String] = userDefaults?.object(forKey: "arrayKey") as? [String] ?? []
This is because UserDefaults must be unwrapped to refer to member object. Give it a try
Based on MrHim recommendations I removed the saveArray and retrieveArray func from the viewDidLoad of my first VC and left retrieveArray in viewDidLoad of my second VC. Having saveArray in my viewDidLoads was overwriting the array with empty data. I then needed to retrieve the array data in the proper place in my second VC. Then in my numberOfRowsInSection I removed retrieveArray.
What I'm trying to accomplish is when user selects an element for UITableView this element gets append to servicioSeleccionadoarray. But I'm stuck in this because if user decides to deselect the cell I want to remove that item from the array. I've try anyarray.remove(at:)but I can figure the way to tapp into that index.
This is my code so far.
class ServicioHogarViewController: UIViewController{
let serviciosHogar = [String](arrayLiteral: "Alfombras", "Muebles Madera", "Sillones", "Marmol", "Aplicación Teflón","Vestiduras", "Salas", "Colchones", "Sillas Oficinas")
#IBOutlet weak var servicioHogarTB1: UITableView!
var selectedIndex : Int? = nil
var servicioSeleccionado : [String] = []
#IBAction func doneButton(_ sender: UIButton) {
performSegue(withIdentifier: "datePick2", sender: self)
}
override func viewDidLoad() {
super.viewDidLoad()
servicioHogarTB1.delegate = self
servicioHogarTB1.dataSource = self
servicioHogarTB1.register(UINib(nibName: "ServicioHogarCell", bundle: nil), forCellReuseIdentifier: "servicioCell1")
servicioHogarTB1.separatorStyle = .none
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(true)
print(servicioSeleccionado)
}
}
// MARK : UITabeView Delegation
extension ServicioHogarViewController : UITableViewDelegate, UITableViewDataSource{
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return serviciosHogar.count
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if tableView.cellForRow(at: indexPath)?.accessoryType == .checkmark {
tableView.cellForRow(at: indexPath)?.accessoryType = .none
} else {
tableView.cellForRow(at: indexPath)?.accessoryType = .checkmark
}
if tableView.cellForRow(at: indexPath)?.accessoryType == .checkmark {
servicioSeleccionado.append(serviciosHogar[indexPath.row])
print(servicioSeleccionado)
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "servicioCell1", for: indexPath) as! ServicioHogarCell
let servicio = serviciosHogar[indexPath.row]
cell.servicioLabel.text = servicio
return cell
}
}
If you have an array :
var cast = ["Vivien", "Marlon", "Kim", "Karl"]
and you want to remove "Marlon" from it, you can find the index of Marlon using the func firstIndex(of: Element) -> Int? method for an array and then remove it like so :
if let index = cast.firstIndex(of: "Marlon"){
cast.remove(at: index)
print(cast)
}
That said, on didSelectRowAt run this function for your array and you'll accomplish what you're looking to.
I'm using a UITabBarController to create a contact list, but when I'm trying to save the array to load the data when I restart the app is giving me problems where the data isn't displayed. I'm using UserDefaults to save the data and the restore when the app is restarted.
In this code I sent data from a textfield to the array named list.
import UIKit
class NewContactoViewController: UIViewController {
#IBOutlet weak var input: UITextField!
#IBAction func add(_ sender: Any) {
if (input.text != "") {
list.append(input.text!)
UserDefaults.standard.set(list, forKey: "SavedValue")
input.text = ""
}
}
}
In this code I'm printing the data in a table, and trying to save it with user defaults.
import UIKit
var list = [String]()
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let x = UserDefaults.standard.object(forKey: "SavedValue") as? String {
return (x.count)
}
return (0)
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "cell")
if let x = UserDefaults.standard.dictionary(forKey: "SavedValue") as? String {
cell.textLabel?.text = [x[indexPath.row]]
}
return(cell)
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == UITableViewCellEditingStyle.delete {
list.remove(at: indexPath.row)
myTableView.reloadData()
}
}
override func viewDidAppear(_ animated: Bool) {
myTableView.reloadData()
}
#IBOutlet weak var myTableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
}
}
You are saving an array of strings but you are reading a single string (or even a dictionary) which obviously cannot work. There is a dedicated method stringArray(forKey to read a string array.
Apart from the issue never read from UserDefaults to populate the data source in the table view data source and delegate methods, do it in viewDidLoad or viewWillAppear for example
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if let savedArray = UserDefaults.standard.stringArray(forKey: "SavedValue") {
list = savedArray
}
myTableView.reloadData()
}
Put the data source array in the view controller. A global variable as data source is very bad programming habit.
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var list = [String]()
...
In numberOfRowsInSection return the number of items in list and return is not a function, there are no parentheses
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return list.count
}
Same in cellForRow. Get the item from list and use reusable cells and again, return is not a function.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = list[indexPath.row]
return cell
}
Note :
Consider that UserDefaults is the wrong place to share data between view controllers. Use segues, callbacks or protocol / delegate.
This has stumped me and Ive tried a few ways of doing of tutorials and on stack answers but its still not building.
So basically:
Im getting core data and then placing that into an array. (works fine)
After that Im just display first and last name in the cells (works fine)
User taps on cell to see athleteDetalView
I have placed a few print statements to see where its going wrong.
Thanks In advance for your input.
import UIKit
import CoreData
class athleteViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
//labels
#IBOutlet weak var athleteLabel: UILabel!
//buttons
#IBOutlet weak var athleteCreate: UIBarButtonItem!
#IBOutlet weak var athleteTableView: UITableView!
var athleteArray:[Athlete] = []
var myIndex = 0
override func viewDidLoad() {
super.viewDidLoad()
athleteTableView.delegate = self
athleteTableView.dataSource = self
self.fetchData()
self.athleteTableView.reloadData()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return athleteArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "athleteName", for: indexPath)
let name = athleteArray[indexPath.row]
cell.textLabel!.text = name.firstName! + " " + name.lastName!
let athleteName = name.firstName!
let lastName = name.lastName!
let age = name.age!
let sport = name.sport!
let email = name.email!
print(athleteName)
print(lastName)
print(age)
print(sport)
print(email)
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
myIndex = indexPath.row
let currentCell
//let storyboard = UIStoryboard(name: "Main", bundle: nil)
//let destination = storyboard.instantiateViewController(withIdentifier: "athleteDetailsViewController") as! athleteDetailsViewController
//let athName = athleteArray[myIndex]
//testdata
//test data
performSegue(withIdentifier: "athleteDetailsSegue", sender: self)
//self.navigationController?.pushViewController(destination, animated: true)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "athleteDetailsSegue") {
var destination = segue.destination as! athleteDetailsViewController
destination.firstNameString = athleteName
destination.lastNameString = lastName
destination.ageString = age
destination.sportString = sport
destination.emailString = email
//destination.getImage = name.image
}
}
func fetchData(){
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
do{
athleteArray = try context.fetch(Athlete.fetchRequest())
}
catch{
print(error)
}
}
The variables that you are setting in tableView:cellForRowAt:indexPath: are local variables and are not available in the function prepareForSegue:. Try to declaring the variables at the top as properties of the class.