I'm creating a sort of Contact list app w/ Xcode and everything was running smoothly until it came time for the app the actually add the new contact to the Contact list. What happens is that Once the user goes to the ViewController that helps the user create a new contact; the previously added Contact is removed from the list. I've tried to investigate and what I've discovered is that once I create a new Element (or Contact)for the Array; my code for some reason deletes the old Contact and replaces it with the newly created one. Whats also interesting is that by simply going to another page on my app (going to a new ViewController) my app for some reason removes the newly created Contact from the Contact list and leaves my TableView empty.
Here is a breakdown of my Coding and what I've tried:
this is the initial ViewController (I've implemented a TableView and created arrays that are organized in a cell within the TableView)
class ViewController: UIViewController, UITableViewDataSource,UITableViewDelegate {
#IBOutlet var TableView: UITableView!
var names = [String]()
var numbers = [String]()
override func viewDidAppear(animated: Bool) {
TableView.reloadData()
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return names.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! CustomCell
cell.Name.text = names[indexPath.row]
cell.PhoneNumber.text = numbers[indexPath.row]
cell.reloadInputViews()
return cell
}
}
This is Where my user will create a new Contact and how I try to append the new Contact to the contact list
classPickViewController: UIViewController,UIImagePickerControllerDelegate,UINavigationControllerDelegate {
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if Save.touchInside{
var VC :ViewController = segue.destinationViewController as! ViewController
if VC.names.count >= 1 {
VC.names.insert(NameText, atIndex: (VC.names.count)+1)
VC.numbers.insert(PhoneText,atIndex: (VC.numbers.count)+1)
}
else{
VC.names.insert(NameText, atIndex: (VC.names.count)+0)
VC.numbers.insert(PhoneText,atIndex: (VC.numbers.count)+0)
}
}
}
#IBAction func SaveContact(sender: UIButton) {
performSegueWithIdentifier("SaveEm", sender: self)//this takes the usr to the Contact list
}
Here is the code Ive used to initialize my Cells in the TableView (UITableViewCell file)
class CustomCell: UITableViewCell {
#IBOutlet var Name: UILabel!
#IBOutlet var PhoneNumber: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
Your app is navigating from ViewController->classPickViewController->ViewController, so you have a new instance of ViewController which will start with a new empty array.
You should look into unwind segues so that you can move back to the presenting ViewController.
You also need to use something like Core Data to persist your data between executions of your app.
I would store an array of a "Contact" struct rather than having two arrays
reloadInputViews() is an overkill when you are already in the cellForRowAtIndexPath. remove that and put reloaddata appropriately. If needed put again when you know that the control flow is over.
So remove reloadInputViews(), and revisit each view of tableviewcell in cellForRowAtIndexPath instead.
Related
I need the tableView to perform reloadData() after a row has been added via a textView. My tableViews all use the reusable code which works fine.
Below is my Reusable TableViewCode.
class ReusableSubtitleTable: NSObject, UITableViewDataSource, UITableViewDelegate{
let cell = "cell"
var dataArray = [String]()
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) {
print("DataArray count from table view = \(dataArray.count)")
return dataArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let selfSizingCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! SelfSizingCell
let num = indexPath.row
selfSizingCell.titleText.text = (stepText[num])
selfSizingCell.subtitleText.text = dataArray[num]
return selfSizingCell
}
}
The function below uses the reusable code to display the table which works fine.
class DetailViewController: UIViewController {
let step = 13
var tableView: UITableView!
let dataSource = ReusableSubtitleTable()
var selectedEntry: JournalEntry!
var dataModel = [String]()
var didSave = false
var coreDataManager = CoreDataManager()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = dataSource
tableView.dataSource = dataSource
dataSource.dataArray = dataModel
#IBAction func unwindToDetail( _ sender: UIStoryboardSegue) {
dataModel[10] = step11
didSave = coreDataManager.updateEntry(step11: step11, selectedEntry: selectedEntry)
}
}
The problem come in when a user wants to add to the last row. The user taps a button and is taken to the next controller which is a TextView. When user finishes their entry they tap the 'Save' button which returned to the DetailViewController via an unwind. The selectedEntry is saved and the dataModel updated. Now the table view needs to reload to display this added text.
I've tried adding tableView.ReloadData() after didSave. I've tried a Dispatch and tried saving the data before returning from the textView via the unwind but that doesn't work either.
I tried adding the below function to ReusableTableView and called it after the coredata update - there are no errors but it does not reload the table.
func doReload(){
tableView.reloadData()
}
I have verified that the data is saved and it does displays if I return to the summary controller and then go forward the DetailViewController.
Any help is appreciated.
Placing the UITableView reloadData() within either viewWillAppear or viewDidAppear should resolve this issue.
For example:
func viewDidAppear(_ animated: bool) {
super.viewDidAppear(animated)
tableView.reloadData()
}
This is because the view hierarchy isn't yet regarded as "visible" during the segue unwind and why you see it work by going back to reloading the view controller. The reloadData() function, for efficiency, only redisplays visible cells and at the time of the unwind the cells aren't "visible".
Apple Documentation - UITableView.reloadData():
For efficiency, the table view redisplays only those rows that are
visible.
Edit: mentioned at the bottom I was using another stackoverflow question for guidance. Turns out its the same issue that I don't believe ever got solved after the person edited their question. So I copied the exact same issue into my code: How to know which cell was tapped in tableView using Swift
There's probably many things wrong with my code at this point, but the main issue is the very edit at the bottom of the post this author puts on his question. I know that makes this a duplicate then but no one has answered that. All the accepted answers have the same outcome as my issue.
I'm very new to swift and I'm creating a flashcard type app where tapping on a tableview cell for details shows a term and definition. These terms and definitions are stored in two parallel arrays and the index is supposed to be the indexPath.row.
My issue is that int selectedCell which should be the index of the array for whichever cell the user taps always runs the code to display the term and definition before running the code to find the selected cell.
My earlier error before this was that if I made selected cell an optional (var selectedCell: Int?), the program would crash because its nil. To fix that, I made it var selectedCell: Int = 0 and that worked until I realized that no matter what I tap, the first selectedCell will always be 0.
How can I get the selectedCell before the terms and definitions are displayed.
This is the code inside CardViewController, the controller brought up after the user touches a cell for details. There are only two labels (term and definition) so the code is pretty scarce here.
override func viewDidLoad() {
super.viewDidLoad()
// Testing
print("new selectedCell: \(selectedCell)")
// Update labels for term and definition
termLabel.text = "Term: \n" + cards[selectedCell]
definitionLabel.text = "Definition: \n" + details[selectedCell]
}
The code inside CardTableViewController where the very last override func is what gives me the selectedCell. I have checked that the number is correct when tapped, it just runs after cardviewcontroller apparently.
This is the code for CardTableViewController, where it is tableview cells of each term from the flashcard listed.
Not to be confused with CardViewController which is the little detail flashcard screen that pops up
import UIKit
var cards = [String]()
var details = [String]()
var newCard:String = ""
var newDetail:String = ""
var study = [String]()
var selectedCell: Int = 0
class CardTableViewController: UITableViewController {
#IBOutlet var createCardButton: UIBarButtonItem!
override func viewDidLoad() {
super.viewDidLoad()
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return cards.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cardCell", for: indexPath)
cell.textLabel?.text = cards[indexPath.row]
return cell
}
#IBAction func cancel(segue:UIStoryboardSegue) {
}
#IBAction func create(segue:UIStoryboardSegue) {
let addCard = segue.source as! AddCardViewController
newCard = addCard.term
newDetail = addCard.definition
print("term: \(addCard.term)")
print("definition: \(addCard.definition)")
cards.append(newCard)
details.append(newDetail)
study.append(newCard)
tableView.reloadData()
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
selectedCell = indexPath.row
print("selectedCell: ", selectedCell)
}
}
I know it's out of order because of the print statements I put in. Instead, selectedCell should print before new selectedCell. Notice how new selectedCell will be 0 due to initialization (nil if I didn't initialize it) and then is always lagging one cell touch behind what it should be?
the segues for cancel and create are bar button items on the (details of the flashcard screen). They are unwind segues that I followed some online tutorial on for how to create an text field and unwind.
for background on the addCardViewController and unwind segues, this is the code inside that:
class AddCardViewController: UIViewController {
#IBOutlet weak var cardTerm: UITextField!
#IBOutlet weak var cardDefinition: UITextField!
var term:String = ""
var definition:String = ""
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "createSegue" {
term = cardTerm.text!
definition = cardDefinition.text!
}
}
Here's the printing results for the cell indexes
new selectedCell: 0
selectedCell: 0
new selectedCell: 0
selectedCell: 1
new selectedCell: 1
selectedCell: 1
Honestly not sure if there's a way to call that function first or if I'm choosing the selectedCell wrong (I got the idea off another post on stack overflow: How to know which cell was tapped in tableView using Swift)
Storyboard for my app. Shows the list of cards tableview controller and the card view controller:
So in my storyboard, I set up two ViewControllers (CardsTableViewController and CardViewController)
The segue in between these two view controllers is called CardSegue and is set up to present modally.
The reuse identifier for the prototype UITableViewCell in CardsTableViewController is CardCell.
This is how the CardsTableViewController looks like:
import UIKit
struct Card {
let term: String
let definition: String
}
class CardsTableViewController: UITableViewController {
var selectedCell: Int = 0
let cards: [Card] = [Card(term: "Привет", definition: "Hello"), Card(term: "Да", definition: "Yes")]
override func viewDidLoad() {
super.viewDidLoad()
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return cards.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CardCell", for: indexPath)
cell.textLabel?.text = cards[indexPath.row].term
return cell
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
selectedCell = indexPath.row
performSegue(withIdentifier: "CardSegue", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if let vc = segue.destination as? CardViewController {
let selectedCard = cards[selectedCell]
vc.card = selectedCard
vc.selectedCell = selectedCell
}
}
}
This is the CardViewController:
import UIKit
class CardViewController: UIViewController {
var card: Card = Card(term: "<Set me>", definition: "<Set me>")
var selectedCell: Int = 0
#IBOutlet weak var termLabel: UILabel!
#IBOutlet weak var definitionLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
// Testing
print("new selectedCell: \(selectedCell)")
termLabel.text = "Term: \n" + card.term
definitionLabel.text = "Definition: \n" + card.definition
}
}
I created a Card struct which has a term and a definition, both being Strings.
I created an array of two Cards with two Russian words. This is the data we're working with.
In didSelectRowAt indexPath, I have set up the same setting of "selectedCell", which is defined at the top.
Directly after, I call performSegue, which will send the user to the CardViewController, which will display the term and the definition.
The prepare(for segue) method is always called whenever performSegue is called. In the view controller, if you start typing..."prepare(for...." Xcode will probably fill it out for you.
In this method, I get the selected card, and I pass the card to the CardViewController. In this example, I pass selectedCell, but I don't know if it's really necessary, it depends on what you are trying to achieve, I guess.
This is how the two view controllers should be communicating.
Here's some good information about how to pass information from one view controller to the next: See this section: Passing Data Between View Controllers Using Segues
In interface builder, I embedded two instances of a UITableViewController in container views in a UIStackView. Both TableViewControllers are linked to the same custom class document (see code below). The only difference between them is in the data they display. Both have UITableViews that allow multiple selection – but I also want so that selecting anything in one table causes the deselection of everything in the other table, and vice versa. I tried setting this up with delegation, but I don't know how to reference one instance from the other within UITableViewController, to assign each as the delegate of the other.
I couldn't find anything relevant about delegation or about referencing a view controller by anything other than its subclass name. So in my latest attempt, I tried referring to the other child of the parent object. Here's the relevant code:
protocol TableViewSelectionDelegate: AnyObject {
func didSelectInTableView(_ tableView: UITableView)
}
class TableViewController: UITableViewController, TableViewSelectionDelegate {
weak var delegate: TableViewSelectionDelegate?
#IBOutlet var numbersTableView: UITableView!
#IBOutlet var lettersTableView: UITableView!
// Received by segue
var displayables: [Character] = []
override func viewDidLoad() {
super.viewDidLoad()
}
// (It's too soon to determine parents/children in viewDidLoad())
override func viewWillAppear(_ animated: Bool) {
guard let tableViewControllers = parent?.children else {
print("No tableViewControllers found!")
return
}
switch restorationIdentifier {
case "NumbersTableViewController":
for tableViewController in tableViewControllers {
if tableViewController.restorationIdentifier == "LettersTableViewController" {
delegate = tableViewController as? TableViewSelectionDelegate
}
}
case "LettersTableViewController":
for tableViewController in tableViewControllers {
if tableViewController.restorationIdentifier == "NumbersTableViewController" {
delegate = tableViewController as? TableViewSelectionDelegate
}
}
default: print("Unidentified Table View Controller")
}
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
delegate?.didSelectInTableView(tableView)
}
func didSelectInTableView(_ tableView: UITableView) {
switch tableView {
case numbersTableView:
numbersTableView.indexPathsForSelectedRows?.forEach { indexPath in
numbersTableView.deselectRow(at: indexPath, animated: false)
}
case lettersTableView:
lettersTableView.indexPathsForSelectedRows?.forEach { indexPath in
lettersTableView.deselectRow(at: indexPath, animated: false)
}
default: print("Unidentified Table View")
}
}
}
Running the above and tapping in either table results in "Unidentified Table View" printed to the console, and neither table's selections are cleared by making a selection in the other.
Any insights into how I could get the results that I want would be appreciated. If something here isn't clear, let me know, and I'll make updates.
Passing information between two instances of a UITableViewController through delegation is apparently not as complicated as it at first seemed. The only noteworthy part is the setting of the delegate. Within the custom TableViewController class, when one instance is initialized, it needs to set itself as the delegate of the other instance. That's it!
In this case, to reference one instance from within another, one can use the tableViewController's parent to get to the other child tableViewController. Although there might be a better way to do this, see the code for my particular solution. Notably, since the parent property is not yet set just after viewDidLoad(), I needed to set things up in viewWillAppear(). Also note that this approach doesn't require using restorationIdentifiers or tags. Rather, it indirectly determines the tableViewController instance through its tableView property.
The delegated didSelectInTableView() function passes the selectedInTableView that was selected in the other tableViewController instance. Since the delegate needs to clear its own selected rows, the selectedInTableView is not needed for this purpose. That is, for just clearing rows, the function doesn't need to pass anything.
protocol TableViewSelectionDelegate: AnyObject {
func didSelectInTableView(_ selectedInTableView: UITableView)
}
class TableViewController: UITableViewController, TableViewSelectionDelegate {
weak var delegate: TableViewSelectionDelegate?
// Received by segue
var displayables: [Character] = []
override func viewDidLoad() {
super.viewDidLoad()
}
// (It's too soon to determine parents/children in viewDidLoad())
override func viewWillAppear(_ animated: Bool) {
guard let siblingTableViewControllers = parent?.children as? [TableViewController] else { return }
switch tableView {
case siblingTableViewControllers[0].tableView: siblingTableViewControllers[1].delegate = self
case siblingTableViewControllers[1].tableView: siblingTableViewControllers[0].delegate = self
default: print("Unidentified Table View Controller")
}
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
delegate?.didSelectInTableView(tableView)
}
func didSelectInTableView(_ selectedInTableView: UITableView) {
// selectedTableView is NOT the one that needs to be cleared
// The function only makes it available for other purposes
tableView.indexPathsForSelectedRows?.forEach { indexPath in
tableView.deselectRow(at: indexPath, animated: false)
}
}
}
Please feel free to correct my conceptualization and terminology.
I am trying to create a program on Xcode that allows the user to enter multiple data into a table view through a text field (when a button is clicked). When the data is added I would like it to be stored and not be deleted after the app is closed - for this part I believe that I would have to use NSUserDefaults, however, I am unsure how I would save an array of strings? (I'm only familiar with storing a single string).
This is what my view controller currently looks like.
I have not done much on my view controller at all but this is what it currently has.
import UIKit
class NewViewController: UIViewController {
#IBOutlet weak var text: UITextField!
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
/*
// 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.destinationViewController.
// Pass the selected object to the new view controller.
}
*/
}
Let's tackle this step-by-step...
TL;DR - For your convenience, I've put the final code into a sample project on Github. Feel free to use any or all of the code in your apps. Best of luck!
Step 1 - Conform to UITableView Protocols
"...enter multiple data into a table view..."
At a minimum, UITableView requires you to conform to two protocols in order to display data: UITableViewDelegate and UITableViewDataSource. Interface Builder handles the protocol declaration for you if you use the built-in UITableViewController object, but in your case you cannot use that object because you only want the UITableView to take up a portion of the view. Therefore, you must implement the protocols yourself by adding them to ViewController's signature:
Swift 4
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
}
Step 2 - Implement UITableView Protocol Required Methods
Now that you have the protocols declared, Xcode displays an error until three required methods are implemented inside of your ViewController class. The bare minimum implementation for these methods is:
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 0
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
return UITableViewCell()
}
You'll implement these methods later, but at this point your code should compile.
Step 3 - Connect UITableView's Protocols to ViewController
Since you are using a standard UITableView object, ViewController is not connected by default to the code you just implemented in the protocol methods. To make a connection, add these lines to viewDidLoad():
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
}
Alternatively, you could use the CONTROL + DRAG technique in Interface Builder to connect the delegate and data source from your UITableView to ViewController.
NOTE: In this case, self refers to the ViewController since you're inside of the ViewController class.
Step 4 - UITextField Setup
"...through a text field..."
You previously added an IBOutlet for your UITextField that is connected to Interface Builder, so there is nothing more to do here.
Step 5 - IBAction for the Add Button
(when a button is clicked)."
You need to add an IBAction to your ViewController class and connect it to your Add Button in Interface Builder. If you prefer to write code and then connect the action, then add this method to your ViewController:
#IBAction func addButtonPressed(_ sender: UIButton) {
}
If you use Interface Builder and the CONTROL + DRAG technique to connect the action, the method will be added automatically.
Step 6 - Add an Array Property to Store Data Entries
"...save an array of strings..."
You need an array of strings to store the user's entries. Add a property to ViewController that is initialized as an empty array of strings:
var dataArray = [String]()
Step 7 - Finish Implementing UITableView Protocol Methods
At this point you have everything you need to finish implementing UITableView's protocol methods. Change the code to the following:
//1
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
//Do nothing
}
//2
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return dataArray.count
}
//3
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
cell.textLabel?.text = dataArray[indexPath.row]
return cell
}
In the future, if you want to do something when the user taps a cell, you will want to add code to tableView(_:didSelectRowAt:).
You now create the same number of rows as the number of values in dataArray.
To make this work with Interface Builder, make sure you go to the Attributes Inspector for your UITableViewCell and set the Cell Identifier to Cell. Check out the documentation for more on Dequeuing Cells.
Step 8 - Finish Implementing addButtonPressed(_:)
As suggested in #dani's answer, in the action you need to implement code that appends the user's text to the array, but only if the text is not blank or empty. It is also a good idea to check if dataArray already contains the value you entered using dataArray.contains, depending on what you want to accomplish:
if textField.text != "" && textField.text != nil {
let entry = textField.text!
if !dataArray.contains(entry) {
dataArray.append(entry)
textField.text = ""
}
tableView.reloadData()
}
Step 9 - Persist Data with UserDefaults
"When the data is added I would like it to be stored and not be deleted after the app is closed."
To save dataArray to UserDefaults, add this line of code after the line that appends an entry inside of the addButtonPressed(_:) action:
UserDefaults.standard.set(dataArray, forKey: "DataArray")
To load dataArray from UserDefaults, add these lines of code to viewDidLoad() after the call to super:
if let data = UserDefaults.standard.value(forKey: "DataArray") as? [String] {
dataArray = data
}
Try the following:
Create an array that will store all the text entered via the UITextField (ie. var array = [String]()
In the action of that add button, append the text the user has entered in the text field to the array.
if text.text != "" && !text.text.isEmpty {
// append the text to your array
array.append(text.text!)
text.text = "" // empty the `UITextField`
}
In your tableView methods, make the numberOfRows return array.count and just add a UILabel for your custom UITableViewCell that will display each entered item from the array in a separate cell.
if you want to display your data in tableview you need to implement tableview delegates. add a table view cell with a label on it
#IBOutlet weak var text: UITextField!
#IBOutlet weak var tableView: UITableView!
let NSUD_DATA = "dataarray_store"
var dataArray : NSMutableArray!
var userDefault = UserDefaults.standard
override func viewDidLoad() {
super.viewDidLoad()
dataArray = NSMutableArray()
// Do any additional setup after loading the view.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
//MARK:- create a button for adding the strings to array and while clicking that button
func onClickButton(){
let string = text.text
dataArray.add(string)
userDefault.set(dataArray, forKey: NSUD_DATA)
}
for getting array stored in userdefault
func getData() -> NSMutableArray?{
if userDefault.object(forKey: NSUD_DATA) != nil{
return userDefault.array(forKey: NSUD_DATA) as! NSMutableArray
}
return nil
}
class ViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {
#IBOutlet weak var entertxt: UITextField!
#IBOutlet weak var save: UIButton!
#IBOutlet weak var tableview: UITableView!
var names = [String]()
override func viewDidLoad() {
super.viewDidLoad()
if let data = UserDefaults.standard.object(forKey: "todolist") as?[String]
{
names = data
}
}
#IBAction func submit(_ sender: Any) {
if entertxt.text != "" {
names.append(entertxt.text!)
UserDefaults.standard.set(names, forKey: "todolist")
tableview.reloadData()
entertxt.text = ""
}
else
{
print("data not found")
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return names.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! myTableViewCell
cell.namelable.text = names[indexPath.row]
return cell
}
I have made a table view in iOS that displays a list of buddy (friend) requests. For the buddy request cell, I have made it a prototype cell and have given it a custom class that extends from UITableViewCell. When I click the "Accept" button on the cell, I want to remove that row from the requests array I have and remove it from the table view as well.
The three options I have considered are
1) Giving the custom cell a property for row that corresponds to the row in the table, and hence, the row in the requests array. Then, when accept is called, pass that row to the delegate function and call
requests.removeAtIndex(row)
tableView.reloadData()
which updates all the custom cells' row property. This method works. However, is this a bad practice to reload the table data (it's only reloading from the stored array, not making a network request)
2) Giving the custom cell the row property, but then calling
self.requests.removeAtIndex(row)
self.requestsTableView.beginUpdates()
self.requestsTableView.deleteRowsAtIndexPaths([NSIndexPath(forRow:row, inSection: 0)], withRowAnimation: UITableViewRowAnimation.Fade)
self.requestsTableView.endUpdates()
However, this does not update the row value in each of the cells following the deleted cell, and I would somehow either have to update them all, or call reloadData() which isn't what I want to do.
3) Instead of passing the row value, when the "Accept" button is clicked, search for the username in the buddies list, get the index of where it is found, and then delete the row in the table using that index and deleteRowsAtIndexPaths. This seems okay to do, especially since I'll never have a huge amount of buddy requests at once and searching won't require much time at all, but I figure if I had immediate access to the row value, it would make things cleaner.
Here is the code:
View Controller
class RequestsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate, RequestTableViewCellDelegate
{
// Outlet to our table view
#IBOutlet weak var requestsTableView: UITableView!
let buddyRequestCellIdentifier: String = "buddyRequestCell"
// List of buddies who have sent us friend requests
var requests = [Buddy]()
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewDidAppear(animated: Bool) {
self.getBuddyRequests()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
// MARK: -Table View
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return requests.count
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: RequestTableViewCell = tableView.dequeueReusableCellWithIdentifier(buddyRequestCellIdentifier) as! RequestTableViewCell
let buddy = requests[indexPath.row]
let fullName = "\(buddy.firstName) \(buddy.lastName)"
cell.titleLabel?.text = fullName
cell.buddyUsername = buddy.username
cell.row = indexPath.row
cell.delegate = self
return cell
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let buddy = self.requests[indexPath.row]
}
func didAccpetBuddyRequest(row: Int) {
// Remove buddy at the 'row' index
// idea 1: update all cells' 'row' value
//self.requests.removeAtIndex(row)
// reloading data will reload all the cells so they will all get a new row number
//self.requestsTableView.reloadData()
// idea 2
// Using row doesn't work here becuase these values don't get changed when other cells are added/deleted
self.requests.removeAtIndex(row)
self.requestsTableView.beginUpdates()
self.requestsTableView.deleteRowsAtIndexPaths([NSIndexPath(forRow:row, inSection: 0)], withRowAnimation: UITableViewRowAnimation.Fade)
self.requestsTableView.endUpdates()
// idea 3: don't use row, but search for the index by looking for the username
}
// MARK: -API
func getBuddyRequests() {
// self.requests = array of buddy requests from API request
self.requestsTableView.reloadData()
}
}
Custom UITableViewCell and protocol for the delegate call
protocol RequestTableViewCellDelegate {
func didAccpetBuddyRequest(row: Int)
}
class RequestTableViewCell: UITableViewCell {
#IBOutlet weak var titleLabel: UILabel!
#IBOutlet weak var acceptButton: UIButton!
var delegate: RequestTableViewCellDelegate?
var buddyUsername: String?
var row: Int?
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
#IBAction func touchAccept(sender: AnyObject) {
// <code goes here to make API request to accept the buddy request>
self.delegate?.didAccpetBuddyRequest(self.row!)
}
}
Thanks for taking the time to read this, I appreciate any help/best practices that you know that could help me in this situation.
There shouldn't be a problem with giving the cell the indexPath and delegate properties, and then informing the delegate when the Accept button has been tapped. You do need to call reloadData(), though, to update the references in the cells that are affected.
If you wish to minimise the number of reloaded rows, call reloadRowsAtIndexPaths() instead, but I think that creating the loop that creates the NSIndexPath objects will slow your app down just the same.
As an alternative I can suggest you another way:
First add action method to your acceptButton in viewController. Inside that method you can get indexPath of the cell that contains button. Here is implementation
#IBAction func acceptDidTap(sender: UIButton) {
let point = tableView.convertPoint(CGPoint.zeroPoint, fromView: button)
if let indexPath = tableView.indexPathForRowAtPoint(point) {
// here you got which cell's acceptButton triggered the action
}
}