How to implement the "First In First Out" method in a UITableView? - ios

Question

I have implemented some Swift code to reveal cells labels one after the other in a tableView when the users swipes the screen.
To do so, I have a list of words stored in words and only its first item is visible in the tableView. Then, when the user swipes the screen, it sets the label of the next cell with the next word from words. Scrolling is enabled as words contains a long list of words.
In PlayViewController.swift, I handle the UITableView and the gestures while in PlayTableViewCell.swift, I set up the UITableViewCell. In ListViewController.swift, I ask the user what words he/she wants to store in the wordsarray.
PlayViewController.swift
class PlayViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var playTableView: UITableView!
var words = [String]()
var numberOfRevealedLabels = 1
var numberOfGoodAnswers = 0
var numberOfWrongAnswers = 0
var indexGA = 0
var indexWA = 0
override func viewDidLoad() {
super.viewDidLoad()
playTableView.delegate = self
playTableView.dataSource = self
self.playTableView.estimatedRowHeight = 50.0
view.isUserInteractionEnabled = true
let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(self.respondToSwipeGesture))
swipeRight.direction = .right
view.addGestureRecognizer(swipeRight)
let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(self.respondToSwipeGesture))
swipeLeft.direction = .left
view.addGestureRecognizer(swipeLeft)
}
// MARK: Table View Data Source
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return words.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cellIdentifier = "PlayTableViewCell"
guard let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as? PlayTableViewCell else {
fatalError("The dequeued cell is not an instance of PlayTableViewCell.")
}
// Configure the cell...
cell.wordLabel.text = words[indexPath.row]
cell.wordLabel.isHidden = !(indexPath.row <= numberOfRevealedLabels - 1)
return cell
}
#objc func respondToSwipeGesture(gesture: UIGestureRecognizer) {
if let swipeGesture = gesture as? UISwipeGestureRecognizer {
switch swipeGesture.direction {
case UISwipeGestureRecognizer.Direction.right:
indexGA = numberOfRevealedLabels
numberOfRevealedLabels += 1
numberOfGoodAnswers += 1
playTableView.reloadData()
case UISwipeGestureRecognizer.Direction.left:
indexWA = numberOfRevealedLabels
numberOfRevealedLabels += 1
numberOfWrongAnswers += 1
playTableView.reloadData()
default:
break
}
}
}
}
PlayTableViewCell.swift
class PlayTableViewCell: UITableViewCell {
//MARK: Properties
#IBOutlet weak var wordLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
wordLabel.lineBreakMode = .byWordWrapping;
wordLabel.numberOfLines = 0;
wordLabel.isHidden = true
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
ListViewController.swift
class ListViewController: UIViewController, UITextFieldDelegate {
#IBOutlet weak var titleTextField: UITextField!
#IBOutlet weak var nametextField: UITextField!
#IBOutlet weak var dataTableView: UITableView!
#IBOutlet weak var saveButton: UIBarButtonItem!
var data = [String]()
//MARK: Properties
var list: List?
//MARK: ViewDidLoad
override func viewDidLoad() {
super.viewDidLoad()
// Handle the text field’s user input through delegate callbacks.
titleTextField.delegate = self
nametextField.delegate = self
// Set up views if editing an existing List.
if let list = list {
navigationItem.title = list.name
titleTextField.text = list.name
data = list.content
}
// Enable the Save button only if the title field has a valid List name
updateSaveButtonState()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func addNameToTable(_ sender: Any) {
guard let word = nametextField.text else {
return
}
data.append(word)
dataTableView.reloadData()
}
#IBAction func playGame(_ sender: Any) {
}
//MARK: UITextFieldDelegate
func textFieldDidBeginEditing(_ textField: UITextField) {
// Disable the Save button while editing
if (textField == titleTextField) {
saveButton.isEnabled = false
} else {
saveButton.isEnabled = true
}
}
func textFieldDidEndEditing(_ textField: UITextField) {
updateSaveButtonState()
navigationItem.title = titleTextField.text
guard let word = nametextField.text else {
return
}
if (textField == nametextField) {
data.append(word)
dataTableView.reloadData()
}
}
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
// Hide the keyboard.
textField.resignFirstResponder()
return true
}
//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 isPresentingInAddListMode = presentingViewController is UINavigationController
if isPresentingInAddListMode {
dismiss(animated: true, completion: nil)
} else if let owningNavigationController = navigationController{
owningNavigationController.popViewController(animated: true)
} else {
fatalError("The ListViewController is not inside a navigation controller.")
}
}
// This method lets you configure a view controller before it's presented.
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if (segue.identifier == "playGame") {
// Passing words list to the PlayViewController
let detailVC = segue.destination as! PlayViewController;
detailVC.words = data
}
super.prepare(for: segue, sender: sender)
// Configure the destination view controller only when the save button is pressed.
guard let button = sender as? UIBarButtonItem, button === saveButton else {
os_log("The save button was not pressed, cancelling", log: OSLog.default, type: .debug)
return
}
let name = titleTextField.text ?? ""
list = List(name: name, content: data)
}
//MARK: Private Methods
private func updateSaveButtonState() {
// Disable the Save button if the text field is empty.
let name = titleTextField.text ?? ""
saveButton.isEnabled = !name.isEmpty
}
}
//MARK: Extension
extension ListViewController : UITableViewDelegate, UITableViewDataSource{
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}// Default is 1 if not implemented
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int{
return data.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCell(withIdentifier: "cell")
cell!.textLabel?.text = data[indexPath.row]
return cell!
}
public func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat{
return 50
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let editAction = UITableViewRowAction(style: .default, title: "Edit", handler: { (action, indexPath) in
let alert = UIAlertController(title: "", message: "Edit list item", preferredStyle: .alert)
alert.addTextField(configurationHandler: { (textField) in
textField.text = self.data[indexPath.row]
})
alert.addAction(UIAlertAction(title: "Update", style: .default, handler: { (updateAction) in
self.data[indexPath.row] = alert.textFields!.first!.text!
self.dataTableView.reloadRows(at: [indexPath], with: .fade)
}))
alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
self.present(alert, animated: false)
})
let deleteAction = UITableViewRowAction(style: .default, title: "Delete", handler: { (action, indexPath) in
self.data.remove(at: indexPath.row)
self.dataTableView.reloadData()
})
return [deleteAction, editAction]
}
}
And it works fine.
Now, I'd like to prompt each item of words FIFO-style (First In First Out) in a tableView with a fixed number of rows.
Let's say I have a 3-rows tableView:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3
}
And words contains 5 items:
word1
word2
word3
word4
word5
I'd like to display each of them in this order:
First word Second word Third word Fourth word Fifth word
------------ ------------ ------------ ------------ ------------
| word1 | | word1 | | word1 | | word2 | | word3 |
------------ ------------ ------------ ------------ ------------
| | | word2 | | word2 | | word3 | | word4 |
------------ ------------ ------------ ------------ ------------
| | | | | word3 | | word4 | | word5 |
------------ ------------ ------------ ------------ ------------
What changes do I need to implement in PlayViewController.swift to recreate this FIFO animation?
My goal here is to eliminate the scrolling and make it easier to read, and also to help the swipes as they seem to be undetectable when performed over a scrollable tableView.
I'm not sure if I need to rewrite a bigger part of my code or changing a few lines in PlayViewController.swift could do the trick.
Thanks for your help!