How to reload a collectionview when I tap on back? - swift

Question

My collectionview did not reload when I tap back from the tableview where I the list reorder.
I have read a few topics but I don't know what's wrong. Can anybody find it?
And can I the speak part of the code place in an apart swift file and include this ViewController. So yes, how? Because I use that in more ViewControllers.
Below is my code.
Thank you very much.
import UIKit
import AVFoundation
class CollectionViewController: UICollectionViewController {
#IBOutlet var soundBoard: UICollectionView!
var list = ["January","February","March","April","May","June", "July","August","September","October","November", "December"]
var bgColor = [""]
var buttonOn: Bool = true
override func viewDidLoad() {
super.viewDidLoad()
let blockItems = UserDefaults.standard.object(forKey:"soundboard")
if(blockItems != nil) {
list = blockItems as! [String]
}
let itemSize = UIScreen.main.bounds.width/2 - 2
let itemHeight = itemSize / 2
let layout = UICollectionViewFlowLayout()
layout.sectionInset = UIEdgeInsetsMake(3, 0, 3, 0)
layout.itemSize = CGSize(width: itemSize, height: itemHeight)
layout.minimumInteritemSpacing = 3
layout.minimumLineSpacing = 3
soundBoard.collectionViewLayout = layout
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
self.collectionView!.reloadData()
}
// MARK: - Collection View
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of items
return list.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> MyCollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! MyCollectionViewCell
cell.cellTitle.text = list[indexPath.row]
return cell
}
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
Speak(currentTitle: list[indexPath.row])
}
// MARK: - Speak function
let synth = AVSpeechSynthesizer()
var myUtterance = AVSpeechUtterance(string: "")
func Speak(currentTitle: String) {
if !synth.isSpeaking {
// Controleert volume
let volume = AVAudioSession.sharedInstance().outputVolume
if volume < 0.5 {
MuteButton()
}
// Spreekt de tekst uit
let myUtterance = AVSpeechUtterance(string: currentTitle)
myUtterance.rate = 0.4
myUtterance.volume = 1
if let theVoice = UserDefaults.standard.object(forKey:"voice") {
myUtterance.voice = AVSpeechSynthesisVoice(language: theVoice as? String)
}
synth.speak(myUtterance)
}
}
func MuteButton() {
let alertController = UIAlertController(title: "Check your volume", message:
"Please check your volume or mute button.", preferredStyle: UIAlertControllerStyle.alert)
alertController.addAction(UIAlertAction(title: "Close", style: UIAlertActionStyle.default,handler: nil))
self.present(alertController, animated: true, completion: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
// MARK: -- Save UserDefaults
func save() {
UserDefaults.standard.set(self.list, forKey:"soundboard")
UserDefaults.standard.synchronize()
self.collectionView?.reloadData()
}
// MARK: -- Add new sound item
#IBAction func addNew(_ sender: Any) {
let alertController = UIAlertController(title: "Create a new sound", message: "", preferredStyle: UIAlertControllerStyle.alert)
alertController.addTextField { (textField: UITextField) in
textField.keyboardAppearance = .dark
textField.keyboardType = .default
textField.autocorrectionType = .default
textField.placeholder = "Type something here"
textField.clearButtonMode = .whileEditing
}
alertController.addAction(UIAlertAction(title: "Create", style: .default) { [weak alertController] _ in
if let alertController = alertController {
let loginTextField = alertController.textFields![0] as UITextField
self.list.append( loginTextField.text!)
self.save()
}
})
alertController.addAction(UIAlertAction(title: "Cancel", style: UIAlertActionStyle.default,handler: nil))
self.present(alertController, animated: true, completion: nil)
}
}

Answer 1

Two things are happening here. First you appear to have two different collection views in CollectionViewController; collectionView which is inherited from the superclass and soundboard which you declare. In viewWillAppear you tell collectionView to reload. If this is not the one that is hooked up in IB nothing will work.
The second issue is that while in soundboardTableViewController you update the user default with the correct data you never read it after the view loads in CollectionViewController.
You should move this:
let blockItems = UserDefaults.standard.object(forKey:"soundboard")
if(blockItems != nil) {
list = blockItems as! [String]
}
into viewWillAppear before your call to reload the collection view and then verify you are telling the right collection view to reload.

Answer 2

I see a few things that could be going wrong here. It would help to see the code in the other view controller however.
First are you sure that you're reordering your model array properly? Remember in swift an array is a value type. Meaning that if you pass the array to another view you're passing a copy of that array and not the array in your collection view controller. It may be a better idea to wrap your model array in an object which you can pass a reference to. More on that here.
Also it's better to tie a reload to a change in your model instead of the view lifecycle. To do that with your current code you could do something like this:
var list = ["January","February","March","April","May","June", "July","August","September","October","November", "December"] {
didSet {
self.collectionView?.reloadData()
// or
self.soundBoard.reloadData()
// I'm confused about which collection view you're using/trying to reload.
}
}
Please let me know if you have any questions. I'll keep an eye out and can edit my answer if needed.

Answer 3

This is the code of the other ViewController where you can reorder the rows and can tap on < Back.
import UIKit
class soundboardTableViewController: UITableViewController {
var list = ["January","February","March","April","May","June", "July","August","September","October","November", "December"]
override func viewDidLoad() {
super.viewDidLoad()
self.navigationItem.rightBarButtonItem = self.editButtonItem
let blockItems = UserDefaults.standard.object(forKey:"soundboard")
if(blockItems != nil) {
list = blockItems as! [String]
}
}
// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
// #warning Incomplete implementation, return the number of sections
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
return list.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = list[indexPath.row]
return cell
}
// Override to support conditional editing of the table view.
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
// Return false 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, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete {
list.remove(at: indexPath.row)
UserDefaults.standard.set(self.list, forKey:"soundboard")
UserDefaults.standard.synchronize()
tableView.reloadData()
}
}
// Override to support rearranging the table view.
override func tableView(_ tableView: UITableView, moveRowAt indexPath: IndexPath, to: IndexPath) {
/*let itemToMove = list[indexPath.row]
list.remove(at: indexPath.row)
list.insert(itemToMove, at: indexPath.row)
UserDefaults.standard.set(self.list, forKey:"soundboard")
UserDefaults.standard.synchronize()*/
let itemToMove = list[indexPath.row]
list.remove(at: indexPath.row)
list.insert(itemToMove, at: to.row)
UserDefaults.standard.set(self.list, forKey:"soundboard")
}
override func setEditing(_ editing: Bool, animated: Bool) {
super.setEditing(editing, animated: animated)
if(self.isEditing) {
}
}
// Override to support conditional rearranging of the table view.
override func tableView(_ tableView: UITableView, canMoveRowAt indexPath: IndexPath) -> Bool {
// Return false if you do not want the item to be re-orderable.
return true
}
// 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.
}
}