I have an app that allows users to save different quotes. The data gets saved in a user account using Firebase. If a user wants to see what quotes they saved, they can do so in the app as well. They simply click a button, which goes to a separate view controller and displays all saved quotes in a table view. The issue I'm having is that the same quote can be saved multiple times. So, I would like to be able to have the app check the content of the tableview and, if a quote is already saved in the table, change the save button to a saved button. Any thoughts on how to go about this?
This is what I use to save to Firebase:
import UIKit
import FirebaseDatabase
import FirebaseAuth
class QuotesViewController: UIViewController {
var ref: DatabaseReference?
override func viewDidLoad() {
super.viewDidLoad()
configureItems()
ref = Database.database().reference()
#IBAction func saveButton(_ sender: UIButton) {
guard let user = Auth.auth().currentUser?.uid else { return }
ref!.child("users").child(Auth.auth().currentUser!.uid).child("Quotes").childByAutoId().setValue(quotesLabel.text!)
}
}
To retrieve data:
import UIKit
import FirebaseDatabase
import FirebaseAuth
class SavedQuotesViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var ref: DatabaseReference?
var databaseHandle: DatabaseHandle?
var postData = [String]()
#IBOutlet weak var tableView: UITableView!
#IBOutlet weak var textLabel: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
ref = Database.database().reference()
databaseHandle = ref?.child("users").child(Auth.auth().currentUser!.uid).child("Quotes").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 = tableView.dequeueReusableCell(withIdentifier: "PostCell")
cell?.textLabel?.text = postData[indexPath.row]
cell?.textLabel?.numberOfLines = 0
return cell!
}
}
As jnpdx said in their comment, you are thinking about this wrong. The table view is a View object. It doesn't store data, it presents it to the user and provides an interface for the user to interact with that data.
You want a model of some kind to store your data. Your Firebase database might be that model, or you might load your records into a model object in memory. I assume you've already made those decisions. (I haven't used Firebase, so I don't know if it's fast enough to serve up data for a table view or not. I suspect not. In order to support smooth scrolling, you want to be able to serve up cells as fast as possible.)
You need a way to tell if your quote is unique. As Claude suggested in his comment, you might want to set up your quote string in Firebase to be hashed/indexed. If you do that testing for uniqueness will be really fast. When the user enters a new quote, you could query the database with the quote string (or it's hash) and see if a record already exists with that hash. If it does, you could update the UI to tell the user that the quote already exists.
Related
I have a UIView which displays some information such as a user's Name and more, including a list of objects that all get pulled from my database. This works fine.
However, I now have a ViewController that gets presented on top of the current ViewController. In this presented ViewController, I am adding Data to my Database. When dismissing that view, I want the original ViewController to update all of its content to be up to date.
Right now, all my views are getting layedout in ViewDidLoad, meaning that they only really get loaded once and don't reload later on. I have managed to update Layout by calling self.view.layoutIfNeeded(), but if I understand correctly, this only updates constraint. Of course, I could call a new init of my original view controller. This would make it reload, but I would like to avoid that.
Another Idea I had was to set up all my content in the ViewWillAppear, which should maybe then update anytime my view controller is about to be visible. However, I don't know how to go about doing this. Can I just move all my setup code to viewWillAppear? Does this have any disadvantages?
TLDR: Is there a way to update a stackview with new elements without having to reload the full ViewController over ViewWillAppear?
The UITableView element works very smoothly with database data. If you fetch the data from your database inside viewDidLoad in your first view controller, and store it in an array, the UITableView (if you set up its dataSource correctly) will automatically populate the table with the new values from the second view controller. With this method, there is no need to use ViewWillAppear at all.
It sounds like as of now, you're using Views (inside a VStack)? to display individual objects from the database. If you want to keep whatever custom style/layout you're using with your views, this can be done by defining a custom subclass of UITableViewCell and selecting the "Also create XIB file" option. The XIB file lets you customize how the cells in your UITableView look.
Here is a simple example to show the database values in the first view controller automatically updating. I didn't include the custom XIB file (these are all default UITableViewCells), to keep it streamlined.
FIRST VIEW CONTROLLER
import UIKit
import CoreData
class ViewController: UIViewController {
#IBOutlet weak var dataTable: UITableView!
var tableRows: [DataItem] = []
func loadData() {
let request: NSFetchRequest<DataItem> = DataItem.fetchRequest()
do {
tableRows = try Global_Context.fetch(request)
} catch {
print("Error loading data: \(error)")
}
}
override func viewDidLoad() {
super.viewDidLoad()
dataTable.dataSource = self
loadData()
}
#IBAction func goForward(_ sender: UIButton) {
self.performSegue(withIdentifier: "toSecond", sender: self)
}
}
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return tableRows.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "dataTableCell", for: indexPath)
cell.textLabel?.text = tableRows[indexPath.row].name
return cell
}
}
let Global_Context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
func saveContext () {
if Global_Context.hasChanges {
do {
try Global_Context.save()
} catch {
let nserror = error as NSError
print("Error saving database context: \(nserror), \(nserror.userInfo)")
}
}
}
SECOND VIEW CONTROLLER:
import UIKit
import CoreData
class AddViewController: UIViewController {
#IBOutlet weak var itemEntry: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
itemEntry.delegate = self
}
#IBAction func addNewItem(_ sender: UIButton) {
let newDataItem = DataItem(context: Global_Context)
newDataItem.name = itemEntry.text
saveContext()
}
#IBAction func goBack(_ sender: UIButton) {
self.performSegue(withIdentifier: "toFirst", sender: self)
}
}
extension AddViewController: UITextFieldDelegate {
func textFieldShouldReturn(_ textField: UITextField) -> Bool {
textField.endEditing(true)
return true
}
}
Main.storyboard:
Once you set up your view controller as a UITableViewDataSource (as in the example code), the table view should make things simpler by eliminating any need to manually manage individual Views.
Is this the functionality you were looking for? (Note about the example: it was set up in Xcode with "Use Core Data" enabled.)
Here is a link to the official documentation:
https://developer.apple.com/documentation/uikit/uitableview
i am using a view based NSTableView with a column that shows dates, and the table cell views use a shared DateFormatter.
let view: NSTableCellView? = tableView.makeView(withIdentifier: column.identifier, owner: self) as! NSTableCellView?
let entry = (logController.arrangedObjects as! [LogEntry])[row]
switch column.identifier {
case columnDateKey:
view?.textField?.formatter = sharedDateFormatter
view?.textField?.objectValue = entry.date
The application has a user preference to choose the date format and previously the code
tableView.setNeedsDisplay(tableView.rect(ofColumn: tableView.column(withIdentifier: columnDateKey)))
would refresh the column with the new date format.
With macOS Mojave this does not happen. Investigation shows that although the drawRect: is called for the underlying TableView there are no calls made to tableView(:viewFor:row:) to obtain the new values for table cell views. Calling tableView.reloadData(forRowIndexes:columnIndexes:) does result in calls to tableView(:viewFor:row:) but the display does not refresh (although it does for tableView.reloadData()).
Any external cause to redraw e.g. selecting a row correctly updates that area alone. The other thing I've seen is that with a long table slowly scrolling up will eventually result in the new format appearing although existing cells do not change when scrolled back to until scrolled a long way past before returning. This would seem to infer that there are cached views that are not considered to have changed when only the configuration of the attached formatter changes (although are when the value of the contents changes)
This behaviour changed with the introduction of Mojave and I am finding it difficult to believe that no-one else has reported it and so am beginning to question my original code. Am I missing something?
The following test code demonstrates the problem, the "View requested" message is not printed for variants of setNeedsDisplay and display is only redrawn for reloadData()
styleButton is tick box to toggle number format and refreshButton is action button to request a redraw
Setting the value to a random value will result in expected redraw behaviour
import Cocoa
#NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {
#IBOutlet weak var window: NSWindow!
#IBOutlet weak var table: NSTableView!
#IBOutlet weak var styleButton: NSButton!
#IBOutlet weak var refreshButton: NSButton!
#IBOutlet weak var testView: NSView!
let numberFormatter = NumberFormatter()
func applicationWillFinishLaunching(_ notification: Notification) {
numberFormatter.numberStyle = symbolButton.state == NSControl.StateValue.on ? NumberFormatter.Style.decimal : NumberFormatter.Style.none
}
#IBAction func refresh(sender: Any?) {
numberFormatter.numberStyle = styleButton.state == NSControl.StateValue.on ? NumberFormatter.Style.decimal : NumberFormatter.Style.none
table.setNeedsDisplay(table.rect(ofColumn: 0))
// table.needsDisplay = true
// table.reloadData(forRowIndexes: IndexSet(integersIn: 0..<table.numberOfRows), columnIndexes:[0])
// table.reloadData()
}
}
extension AppDelegate: NSTableViewDataSource {
func numberOfRows(in tableView: NSTableView) -> Int {
if tableView == table {
return 40
}
return 0
}
}
extension AppDelegate: NSTableViewDelegate {
func tableView(_ tableView: NSTableView, viewFor tableColumn: NSTableColumn?, row: Int) -> NSView? {
print("View requested")
guard tableColumn != nil else {
return nil
}
let column = tableColumn!
if tableView == table {
let view: NSTableCellView? = tableView.makeView(withIdentifier: column.identifier, owner: self) as! NSTableCellView?
view?.textField?.formatter = numberFormatter
view?.textField?.objectValue = 123.456
return view
}
return nil
}
}
Incorrectly relying on view.setNeedsDisplay to automatically update subviews. This is not the case (although had appeared to work that way, previously) - refer comment from Willeke above
I'm trying to read data from CoreData into a custom cell. This is just a test app before I try moving to the real app that I've been working on. The data is there - I can print it to the console and see it. For some reason, even with constraints, all of the data is laid on top of each other in the cell. Can anyone see what's going on with this?
I've created constraints to keep the cells where they should be, but when the data is loaded from my 'show data' button, the data is laid on top of each other.
Here is my custom cell class:
import UIKit
class CustomCellClass: UITableViewCell {
#IBOutlet weak var txtNameLabel: UILabel!
#IBOutlet weak var txtAgeLabel: UILabel!
}
Here is the ShowData class: (partial)
class ShowData: UIViewController, NSFetchedResultsControllerDelegate {
#IBOutlet weak var personTableView: UITableView!
let appDelegate = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
var personData = [Person]()
// Read the data
override func viewDidLoad() {
super.viewDidLoad()
personTableView.delegate = self
personTableView.dataSource = self
loadItems()
}
func loadItems() {
let request : NSFetchRequest<Person> = Person.fetchRequest()
do {
personData = try appDelegate.fetch(request)
} catch {
print("couldn't load")
}
}
}
extension ShowData : UITableViewDataSource, UITableViewDelegate {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return personData.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let person = personData[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "personNameAge", for: indexPath) as! CustomCellClass
cell.txtNameLabel?.text = person.name
cell.txtAgeLabel?.text = String(person.age)
return cell
}
Here is a screenshot of the tableview while running:
Edit:
I just deleted the app from the simulator and tried to rerun - now there isn't any data in the cells.
Just to clarify for other readers, as can be seen in your screenshot, the rows in your table are separated as expected but the different fields in each cell, what one might call the columns, are on top of one another.
You say that you have created constraints to keep the cells where they should be, I'm not sure what you mean by that. What you need is constraints for the fields within each cell – what I call intra-cell constraints. Either you have not added these constraints, or there is a mistake in them which causes all fields to be drawn at the left.
To show you what I mean, let's use the example of a little workout app of mine which has, in each table cell, from left to right, a Perform button, an Edit button, a Name field and a Duration field. The screenshot below shows, in the big yellow box, the intra-cell constraints. If you are using a storyboard, the problem with your app must be in that area. If you are not using a storyboard, the problem must be in the equivalent code (or lack of it).
Just to let everyone know. The issue is resolved. I removed the table view cell from the project, readded, and readded the constraints. Everything is working now. I'm not sure where the problem was, but I noticed I had weird wrapping happening. I moved one of the labels to the other side of the cell and constrained it to the right side, and the other to the left side. When I ran the app, the text appeared to word wrap. I decided to delete the cell and readd and relink my outlets. It worked the first time...
I am trying to figure out how to get textfield data from cells in a tableview in an ordered fashion. So far I am able to type into each textfield a retrieve the type data. To do so in the correct order though the user must edit the first cell...last cell, any other way and the data isn't in the correct order.
For Example:
I have the program create 5 cells with a textfield,
textfield1: I typed here second
textfield2: I typed here fourth
textfield3: I typed here first
textfield4: I typed here fifth
textfield5: I typed here third
the way I currently have it my dataArray would look identical to this one, because it is being stored based on when it is typed in and not the order of the cells.
I would like to type the above example, but my data come out like this:
textfield1: I typed here first
textfield2: I typed here second
textfield3: I typed here third
textfield4: I typed here fourth
textfield5: I typed here fifth
Here is my textfield editing code:
#IBAction func TitleEditBegin(_ sender: UITextField) {
}
#IBAction func TitleEditEnd(_ sender: UITextField) {
print(sender.tag) // Debug
titleArray.append(sender.text!)
}
I know for the time being that any other changes will be appended to the titleArray, but I want to solve the ordering issue first.
Thanks!
EDIT: I forgot to add in how I am creating the cells, the code is below:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = TitleSessionTableView.dequeueReusableCell(withIdentifier: textCellIdentifier, for: indexPath) as! TitleSessionCell
cell.SessionTitleLabel.text = "Title"
// cell.SessionTitleField.text = "Default"
cell.SessionTitleField.tag = indexPath.row
cell.SessionTitleField.delegate = self
print(indexPath.row) // Debug
return cell
}
EDIT 2: Adding where I define the text fields.
import Foundation
import UIKit
class TitleSessionCell: UITableViewCell{
#IBOutlet weak var SessionTitleField: UITextField!
#IBOutlet weak var SessionTitleLabel: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
}
}
The easiest way would be to use a dictionary I believe. I would assign all of the textFields a different tag. So for textField1 you would say textField1.tag = 1. I don't see the creation of your text fields, so it is hard to show the best way of adding that in, but then after handling that, I would create the dictionary as a class variable.
var textFieldDictionary: [Int: String] = [:]
and then add in the text to it like so:
if sender.text != nil && sender.text != "" {
textFieldDictionary[sender.tag] = sender.text
}
then when you want to retrieve the information, do something like this:
for i in 0..<biggestTextFieldNumber {
if let text = textFieldDictionary[i] {
//do something with text
print(text)
}
}
or you could just grab the specific number values out whenever you needed them by using:
textFieldDictionary[numberYouWant]
I hope this helps!
I have looked up many examples and tried to incorporate but have been unsuccessful. In my CollectionView (That has been placed in a ViewController), I'd like to select a cell and push the cell image to another ViewController. The references to images have been placed in an Array of Dictionaries within a plist file. I'm not sure, how i should edit both my prepareForSegue or my func collectionView...didSelectItemAtIndexPath. Also, any detailed explanation to go along with your code will be helpful as I'm still learning swift and its syntax.
Below is what i think all the information you need but please let me know if you need more:
func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {}
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if (segue.identifier == "ShowToStory") {
var story = sender as! UICollectionViewCell, indexPath = collectionView.indexPathForCell(story)
}
}
private func initStoryImages() {
var storyArchives = [StoryImages]()
let inputFile = NSBundle.mainBundle().pathForResource("StoryArchive", ofType: "plist")
let inputDataArray = NSArray(contentsOfFile: inputFile!)
for inputItem in inputDataArray as! [Dictionary<String, String>] {
let storyImage = StoryImages(dataDictionary: inputItem)
storyArchives.append(storyImage)
}
storyImages = storyArchives
}
ADDITIONAL CLASS: CollectionViewCell class
class CollectionViewCell: UICollectionViewCell {
#IBOutlet weak var cellImage: UIImageView!
func setStoryImage(item:StoryImages){
cellImage.image = UIImage(named:item.itemImage)
}
}
ADDITIONAL CLASS: UIViewController (Edit_1)
class StoryView: UIViewController{
#IBOutlet weak var ImageToStory: UIImageView!
var story: Story?
override func viewWillAppear(animated: Bool) {
if let story = story {
ImageToStory.image = UIImage(named: story.imageName)
}
}
}
Your story view should have public setter for story image. Then You can use prepareForSegue method to pass data. If You still have problems consider watching some videos from Stanford University iOS programming lecture on iTunes U, it is free and this topic is widely covered there.