I'm trying to append string using an alert in createPlaylistVC to a tableView in another ViewController createdPlaylistVC.
I've looked up this answer and it didn't do much for me
add a row to the tableView from another viewController
CreatePlaylistVC
var crdPlaylistVC = CreatedPlaylistVC()
alert.addAction(UIAlertAction(title:"OK", style:.default, handler: {
action in
if let playlistName = alert.textFields?.first?.text {
self.crdPlaylistVC.emptyArray.append("Your playlist: \(playlistName)")
let indexPath = IndexPath(row: self.crdPlaylistVC.emptyArray.count - 1, section: 0)
self.crdPlaylistVC.tableView?.beginUpdates()
self.crdPlaylistVC.tableView?.insertRows(at: [indexPath], with: .automatic)
self.crdPlaylistVC.tableView?.endUpdates()
self.crdPlaylistVC.tableView?.reloadData()
func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let SEC: CreatedPlaylistVC = segue.destination as! CreatedPlaylistVC
SEC.emptyArray.append("Your playlist: \(playlistName)")
self.crdPlaylistVC.tableView.reloadData()
}
CreatedPlaylistVC
class CreatedPlaylistVC:UIViewController, UITableViewDataSource, UITableViewDelegate {
#IBOutlet weak var tableView: UITableView!
var emptyArray = [String]()
override func viewDidLoad() {
super.viewDidLoad()
tableView.dataSource = self
tableView.delegate = self
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "playlistCell", for: indexPath) as! UITableViewCell
cell.textLabel?.text = emptyArray[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return emptyArray.count
}
}
The code cannot work. createdPlaylistVC() is never the instance in the storyboard.
You have to call performSegue in the action and pass the string as sender. And prepare for must be on the top level of the class
var crdPlaylistVC = createdPlaylistVC()
alert.addAction(UIAlertAction(title:"OK", style:.default) { [weak self] action in
if let playlistName = alert.textFields?.first?.text {
self?.performSegue(withIdentifier: "MyIdentifier" sender: playlistName)
}
}
func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard segue.identifier == "MyIdentifier" else { return }
let playlistName = sender as! String
let sec = segue.destination as! createdPlaylistVC
sec.emptyArray.append("Your playlist: \(playlistName)")
}
You have to reload the table view in createdPlaylistVC because the table view might be not connected yet.
And please conform to the naming convention that class names start with an uppercase letter and variable names start with a lowercase letter.
Related
I'm coding a Note App in Swift 4. The root ViewController (NoteListViewController) gets populated when secondViewController (ComposeNoteViewController) Textfield and TextView are populated.
The problem is when I press a populated TableView cell, rather than fetch and display the content, it opens a fresh instance of theComposeNoteViewController.
import UIKit
import CoreData
class NoteListTableViewController: UITableViewController {
var noteListArray = [NoteListItem]()
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
override func viewDidLoad() {
super.viewDidLoad()
loadNoteListItem()
}
// MARK: - Table view data source
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return noteListArray.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "NoteListItemCell", for: indexPath)
cell.textLabel?.text = noteListArray[indexPath.row].title
return cell
}
//MARK: - TABLEVIEW DELEGATE METHODS
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "goToComposeNote", sender: self)
tableView.deselectRow(at: indexPath, animated: true)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let destinationVC = segue.destination as! ComposeNoteViewController
if let indexPath = tableView.indexPathForSelectedRow {
destinationVC.selectedNoteList = noteListArray[indexPath.row]
}
}
import UIKit
import CoreData
class ComposeNoteViewController: UIViewController {
var noteComposeItemsArray = [ComposeNote]()
var noteListArray = [NoteListItem]()
// let noteListController = NoteListTableViewController()
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
var selectedNoteList : NoteListItem? {
didSet {
loadComposeItem()
}
}
#IBOutlet weak var noteTextView: UITextView!
#IBOutlet weak var noteTextField: UITextField!
#IBAction func noteSavePressed(_ sender: UIBarButtonItem) {
let newNoteTitleItem = NoteListItem(context: context)
let newComposeNote = ComposeNote(context: context)
newNoteTitleItem.title = noteTextField.text!
newComposeNote.note = noteTextView.text!
newComposeNote.parentTitleNote = selectedNoteList
noteComposeItemsArray.append(newComposeNote)
noteListArray.append(newNoteTitleItem)
saveComposeItems()
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
}
func saveComposeItems() {
do {
try context.save()
}catch {
print("Error saving context \(error)")
}
reloadInputViews()
}
func loadComposeItem() {
let request : NSFetchRequest<ComposeNote> = ComposeNote.fetchRequest()
let predicate = NSPredicate(format: "parentTitleNote.title MATCHES %#", selectedNoteList!.title!)
request.predicate = predicate
do {
noteComposeItemsArray = try context.fetch(request)
}catch {
print("Can't load Items")
}
reloadInputViews()
}
}
I have a chat app and want to go from my ChatController to a newMessageVC by using a modal segue. In newMessageVC I got all my contacts shown in a table view. When clicking on a contact the newMessaenter code heregeVC should dismiss and the clicked contact should be sent to ChatController. In this moment the ChatController should perform a segue to go to the ChatVC to show the new chat with the clicked user. How can I do this?
I tried following code:
The newMessageVC is dismissing and the function showChatVC is called (It shows the print statement) but then there is the Error although the segue does exist. There is a segue from ChatController to ChatVC named showChatVC
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Receiver (<WeAreFriends.ChatController: 0x7fd760e22e80>) has no segue with identifier 'showChatVC''
class ChatController : UITableViewController {
//MARK: - Outlets
#IBOutlet weak var MessageTableView: UITableView!
//MARK: - Properties
var messages = [MessageModel]()
//Mark: - Init View Lifecycle
override func viewDidLoad() {
super.viewDidLoad()
configureNavigationBar()
}
//MARK: - Navigation Bar
func configureNavigationBar() {
navigationItem.title = "Messages"
navigationController?.navigationBar.barTintColor = Defaults.hexStringToUIColor(hex: "#006D79")
let textAttributes = [NSAttributedString.Key.foregroundColor: Defaults.hexStringToUIColor(hex: "#FFAA01")]
navigationController?.navigationBar.titleTextAttributes = textAttributes
navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(handleNewMessage))
}
#objc func handleNewMessage(){
performSegue(withIdentifier: "showNewMessage", sender: self)
}
//MARK: - Show ChatVC
func showChatVC(forUser user: UserModel){
print("Shooow, jihaaaaa")
let messageController = MessageController()
messageController.user = user
performSegue(withIdentifier: "showChatVC", sender: self)
}
//MARK: - Prepare for segue
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showNewMessage" {
let destinationVC = segue.destination as! NewMessageController
destinationVC.chatController = ChatController()
}
}
//MARK: - Table Config
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return messages.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MessagesTableViewCell", for: indexPath) as! MessagesTableViewCell
return cell
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("did select row")
}
}
newMessageVC:
class NewMessageController: UITableViewController {
//MARK: - Outlets
#IBOutlet var NewMessageTableView: UITableView!
//MARK: - Var/let
var users = [UserModel]()
var chatController : ChatController?
//Mark: - Init View Lifecycle
override func viewDidLoad() {
super.viewDidLoad()
configureNavigationBar()
fetchUser()
}
//MARK: - User laden
func fetchUser(){
UserApi.shared.observeUsersButCurrentUser { (user) in
self.users.append(user)
self.NewMessageTableView.reloadData()
}
}
//MARK: - Navigation Bar
func configureNavigationBar() {
navigationItem.title = "New Message"
navigationController?.navigationBar.barTintColor = Defaults.hexStringToUIColor(hex: "#006D79")
let textAttributes = [NSAttributedString.Key.foregroundColor: Defaults.hexStringToUIColor(hex: "#FFAA01")]
navigationController?.navigationBar.titleTextAttributes = textAttributes
}
//MARK: - Tableview Config
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return users.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "NewMessageTableViewCell", for: indexPath) as! NewMessageTableViewCell
cell.user = users[indexPath.row]
return cell
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
self.dismiss(animated: true) {
let user = self.users[indexPath.row]
self.chatController!.showChatController(forUser: user)
}
}
}
What am I doing wrong?
Replace
destinationVC.chatController = ChatController()
with
destinationVC.chatController = self
As ChatController() is a new different instance with no storyboard layout attached , so no segues hence the crash
func showChatVC(forUser user: UserModel){
performSegue(withIdentifier: "showChatVC", sender:user)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showNewMessage" {
let destinationVC = segue.destination as! NewMessageController
destinationVC.chatController = ChatController()
}
else if segue.identifier == "showChatVC" {
let destinationVC = segue.destination as! ChatVC
destinationVC.user = sender as! UserModel
}
}
Also make
weak var chatController : ChatController?
As not to cause retain cycles
I want to send text to firebase, and then retrieve it to tableView, but some data too long and don't fit in one line, so i want that data can be open in new controller, how to release it?
My code:
class UserVC: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
var ref: DatabaseReference?
var databaseHandle:DatabaseHandle?
var postData = [String]()
var postOneData = 0
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
ref = Database.database().reference()
databaseHandle = ref?.child("Child").observe(.childAdded, with: { (snapshot) in
let post = snapshot.value as? String
if let actualPost = post {
self.postData.append(actualPost)
self.tableView.reloadData()
}
})
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return postData.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell:UITableViewCell = self.tableView.dequeueReusableCell(withIdentifier: "MySell") as UITableViewCell!
cell.textLabel?.text = self.postData[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
performSegue(withIdentifier: "showText", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showText" {
if let destinationVC = segue.destination as? ShowText {
}
}
}
Assuming that you have a text label in you ShowText
private var textForShowText = String() // a private class variable
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
self.textForShowText = self.postData[indexPath.row]
performSegue(withIdentifier: "showText", sender: self)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showText" {
if let destinationVC = segue.destination as? ShowText {
destinationVC.textLabel.text = textForShowText
}
}
}
Here I am assuming that your ShowText has a UITextLabel named textLabel. Also make sure that the numberOfLines of the text label is set to 0. You can also use a UITextView if you want !!
I'm working on a journal app and now I want people to be able to click on a cell/entry and then go to a more detailed view where they can read/edit their entry. The thing is, the strings I'm trying to pass to the next view aren't coming through.
Edit:
This is the code on the TableViewController:
class TableViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
var items: [Entry] = []
var passedEntry:String = ""
func fetchData() {
do {
items = try context.fetch(Entry.fetchRequest())
print(items)
DispatchQueue.main.async {
self.tableView.reloadData()
}
} catch {
print("Couldn't fetch data")
}
}
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return items.count
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as UITableViewCell
let date = items.reversed()[indexPath.row].date
cell.textLabel?.text = items[indexPath.row].title
if let date = date {
let dateStamp = "Added on \(date)"
cell.detailTextLabel?.text = dateStamp
}
return cell
}
#objc(tableView:editActionsForRowAtIndexPath:) func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let delete = UITableViewRowAction(style: .default, title: "Delete") { (action, indexPath) in
// delete item at indexPath
let item = self.items[indexPath.row]
self.context.delete(item)
(UIApplication.shared.delegate as! AppDelegate).saveContext()
self.items.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
}
return [delete]
}
public func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?){
if (segue.identifier == "showEntry") {
// initialize new view controller and cast it as your view controller
let viewController = EntryViewController()
// your new view controller should have property that will store passed value
viewController.passedEntry = passedEntry
}
}
public func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
passedEntry = items[indexPath.row].title!
self.performSegue(withIdentifier: "showEntry", sender: self)
}
override func viewWillAppear(_ animated: Bool) {
fetchData()
}
This is the code on the EntryViewController which still prints nil:
class EntryViewController: UIViewController {
var passedEntry:String!
#IBOutlet weak var dreamTitle: UITextView!
#IBOutlet weak var dreamPost: UITextView!
#IBAction func saveChanges(_ sender: Any) {
}
override func viewWillAppear(_ animated: Bool) {
print(passedEntry)
}
I'm sorry for being a newbie, but I need some more detailed instructions...
Two issues:
The signature of prepareForSegue is wrong for Swift 3.
Never create view controllers with the default initializer when using storyboard
This main issue occurs in this line:
let viewController = EntryViewController()
You are creating a brand new instance of EntryViewController which is not the controller in the storyboard. You have to use the destination view controller of the segue:
func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "showEntry" {
// initialize new view controller and cast it as your view controller
let viewController = segue.destination as! EntryViewController
// your new view controller should have property that will store passed value
let title = items[indexPath.row].title
viewController.passedEntry = title
}
}
And I recommend to declare the string in the destination view controller as non-optional empty string rather than an implicit unwrapped optional. Non-optional types will never crash the app.
var passedEntry = ""
You are defining prepareForSegue() as a local function inside the tableView-function. It will not be used. Put a debugger breakpoint into it and see yourself if it will be reached.
I have created a NoteBook application within a larger app. I have all the functionality working including a segue to an Add Note page which triggers programatically from clicking a note (to edit it) or a + barButtonItem.
I need a second segue to send the user back to the home page of the app, but every way I seem to try it conflicts with the existing segue I have in place.
Can anyone suggest a way to get the second segue to work. They both have different identifiers which I am referencing in the methods. Its just the goHome segue that will not work...
class NoteBookViewController: UITableViewController, NoteViewDelegate {
func didUpdateNoteWithTitle(newTitle: String, andBody newBody: String) {
self.noteBookEntries[self.selectedIndex] ["title"] = newTitle
self.noteBookEntries[self.selectedIndex] ["body"] = newBody
self.tableView.reloadData()
saveNotesArray()
}
var noteBookEntries = [[String:String]] ()
#IBAction func newNote() {
var newNote = ["title" : "", "body" : ""]
noteBookEntries.insert(newNote, at: 0)
self.selectedIndex = 0
self.tableView.reloadData()
saveNotesArray()
performSegue(withIdentifier: "editNoteBookSegue", sender: nil)
}
var selectedIndex = -1
func saveNotesArray() {
UserDefaults.standard.set(noteBookEntries, forKey: "notes")
UserDefaults.standard.synchronize()
}
override func viewDidLoad() {
super.viewDidLoad()
if let newNote = UserDefaults.standard.array(forKey: "notes") as? [[String:String]] {
noteBookEntries = newNote
}
self.navigationItem.leftBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.reply, target: self, action: #selector(NoteBookViewController.navigateToNextViewController))
}
func navigateToNextViewController(){
self.performSegue(withIdentifier: "goHome", sender: self)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return noteBookEntries.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell (withIdentifier: "CELL")! as UITableViewCell
cell.textLabel?.text = noteBookEntries[indexPath.row]["title"]
return cell
}
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == UITableViewCellEditingStyle.delete {
noteBookEntries.remove(at: indexPath.row)
UserDefaults.standard.set(noteBookEntries, forKey: "notes")
self.tableView.reloadData()
}
}
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
self.selectedIndex = indexPath.row
performSegue(withIdentifier: "editNoteBookSegue", sender: nil)
}
override func prepare(for segue: UIStoryboardSegue, sender: AnyObject?) {
let notesEditorVC = segue.destination as! NewNoteBookEntryViewController
notesEditorVC.navigationItem.title = noteBookEntries[self.selectedIndex] ["title"]
notesEditorVC.noteBodyText = noteBookEntries[self.selectedIndex] ["body"]
notesEditorVC.delegate = self
}
}
error message relating to original segue - this segue works until the second is added
In your prepareForSegue method first line is:
let notesEditorVC = segue.destination as! NewNoteBookEntryViewController
This method is called for each of your segues. When it is called for your first segue it works totally fine because the destination view controller is, in fact, of type NewNoteBookEntryViewController.
However, when this method is called for your second segue, the destination controller is of different type. So, you get a crash when you force downcast it.
You should add some logic to your prepareForSegue method so that you distinguish between segues. For example:
if segue.identifier == "addNote" {
let notesEditorVC = segue.destination as! NewNoteBookEntryViewController
//some other code
}
Solved by adding the logic and then adding this to the destination controller:
override func viewWillAppear(animated: Bool) {
self.navigationController?.setNavigationBarHidden(true, animated: true)
}