I've already looked at the post UITableView.reloadData() is not working. I'm not sure that it applies to my situation, but let me know if I'm wrong.
My app has a tableView. From the main viewController I am opening another viewController, creating a new object, and then passing that object back to the original viewController, where it is added to an array called timers. All of that is working fine. However, when I call tableView.reloadData() in didUnwindFromNewTimerVC() to display the updated contents of the timers array, nothing happens.
NOTE: I have verified that the timers array is updated with the new object. Its count increments, and I can access its members. Everything else in didUnwindFromNewTimerVC() executes normally. The tableView just isn't updating to reflect it.
Here is my code:
import UIKit
class TimerListScreen: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tabelView: UITableView!
var timers = [Timer]()
let tableView = UITableView()
override func viewDidLoad() {
super.viewDidLoad()
tabelView.delegate = self
tabelView.dataSource = self
let tempTimer = Timer(timerLabel: "temp timer")
timers.append(tempTimer)
}
#IBAction func didUnwindFromNewTimerVC(_sender:UIStoryboardSegue){
guard let newTimerVC = _sender.source as? newTimerVC else{return}
newTimerVC.timer.setTimerLabel(timerLabel: newTimerVC.timerLabel.text!)
timers.append(newTimerVC.timer)
tableView.reloadData()
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tabelView.dequeueReusableCell(withIdentifier: "TimerCell", for: indexPath) as? TimerCell{
let timer = timers[indexPath.row]
cell.updateUI(Timer: timer)
return cell
}else{
return UITableViewCell()
}
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return timers.count
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 78
}
}
Thank you
Please note the spelling. There are two table view instances: the outlet tabelView and a (pointless) instance tableView.
Reload the data of the outlet
tabelView.reloadData()
and delete the declaration line of the second instance let tableView ....
However I'd recommend to rename the outlet to correctly spelled tableView (you might need to reconnect the outlet in Interface Builder).
And force unwrap the cell
let cell = tabelView.dequeueReusableCell(withIdentifier: "TimerCell", for: indexPath) as! TimerCell
and remove the if - else part. The code must not crash if everything is hooked up correctly in IB.
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.
Hello the image above is the UI of my todo list app, now I just want to show the detail of item (First Item, second Item etc) when I click the detail button in the tableviewcell. So in order to get the property of the item, I need to know the indexPath of the row that I just clicked on the detail button.
I have tried some properties of the tableview like didSelectRowAt, or indexPathForSelectedRow, but both not work. For didSelectRowAt user need to click on the row first then click the detail button, and that's not what I want, and the indexPathForSelectedRow is not working for me.
A common, generalized solution for this type of problem is to connect the #IBAction of the button to a handler in the cell (not in the view controller), and then use a delegate-protocol pattern so the cell can tell the table when the button was tapped. The key is that when the cell does this, it will supply a reference to itself, which the view controller can then use to determine the appropriate indexPath (and thus the row).
For example:
Give your UITableViewCell subclass a protocol:
protocol CustomCellDelegate: class {
func cell(_ cell: CustomCell, didTap button: UIButton)
}
Hook up the #IBAction to the cell (not the view controller) and have that call the delegate method:
class CustomCell: UITableViewCell {
weak var delegate: CustomCellDelegate?
#IBOutlet weak var customLabel: UILabel!
func configure(text: String, delegate: CustomCellDelegate) {
customLabel.text = text
self.delegate = delegate
}
#IBAction func didTapButton(_ button: UIButton) {
delegate?.cell(self, didTap: button)
}
}
Obviously, when the cell is created, call the configure method, passing, amongst other things, a reference to itself as the delegate:
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { ... }
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
let text = ...
cell.configure(text: text, delegate: self)
return cell
}
}
Finally, have the delegate method call indexPath(for:) to determine the index path for the cell in question:
extension ViewController: CustomCellDelegate {
func cell(_ cell: CustomCell, didTap button: UIButton) {
guard let indexPath = tableView.indexPath(for: cell) else { return }
// use `indexPath.row` here
}
}
The other approach is to use closures, but again using the same general pattern of hooking the button #IBAction to the cell, but have it call a closure instead of the delegate method:
Define custom cell with closure that will be called when the button is tapped:
class CustomCell: UITableViewCell {
typealias ButtonHandler = (CustomCell) -> Void
var buttonHandler: ButtonHandler?
#IBOutlet weak var customLabel: UILabel!
func configure(text: String, buttonHandler: #escaping ButtonHandler) {
customLabel.text = text
self.buttonHandler = buttonHandler
}
#IBAction func didTapButton(_ button: UIButton) {
buttonHandler?(self)
}
}
When the table view data source creates the cell, supply a handler closure:
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { ... }
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
let text = ...
cell.configure(text: text, buttonHandler: { [weak self] cell in // the `[weak self]` is only needed if this closure references `self` somewhere
guard let indexPath = tableView.indexPath(for: cell) else { return }
// use `indexPath` here
})
return cell
}
}
I personally prefer the delegate-protocol pattern, as it tends to scale more nicely, but both approaches work.
Note, in both examples, I studiously avoided saving the indexPath in the cell, itself (or worse, “tag” values). By doing this, it protects you from getting misaligned if rows are later inserted and deleted from the table.
By the way, I used fairly generic method/closure names. In a real app, you might give them more meaningful names, e.g., didTapInfoButton, didTapSaveButton, etc.) that clarifies the functional intent.
Implement the delegate method tableView(_:accessoryButtonTappedForRowWith:)
func tableView(_ tableView: UITableView, accessoryButtonTappedForRowWith indexPath: IndexPath)
However if you want to navigate to a different controller connect a segue to the accessory view button
If the button is a custom button see my answer in Issue Detecting Button cellForRowAt
I am creating a UITableView that enables the user to add a variable amount of data. Table looks like this initially:
When the user clicks on the "+" button, i would like to add a new cell with a UITextField for entering data. This new cell is a Custom UITableViewCell called "RecordValueCell". Here's what is looks like:
//Custom UITableViewCell
class RecordValueCell : UITableViewCell {
#IBOutlet weak var textField: UITextField!
#IBOutlet weak var deleteButton: UIButton!
var onButtonTapped : ((_ sender : UIButton)->Void)?
#IBAction func deleteButtonTouched(_ sender: Any) {
guard let senderButton = sender as? UIButton else {
return
}
onButtonTapped?(senderButton)
}
}
However when i try to add another cell, using the tableView.dequeueReusableCell(withIdentifier: ) function, it seems to return the same cell. And here is what my UI looks like:
Empty space at the top of the section where my new cell should be. Here is the code to add the cell:
func addNewValueCell() {
guard let reusableValueCell = self.tableView.dequeueReusableCell(withIdentifier: "valueCell") as? RecordValueCell else {
fatalError("failed to get reusable cell valueCell")
}
var cell = Cell() //some custom cell Object
//add the gray horizontal line you see in the pictures
reusableValueCell.textField.addBorder(toSide: .Bottom, withColor: UIColor.gray.cgColor, andThickness: 0.5)
reusableValueCell.onButtonTapped = { (sender) in
self.removeValue(sender: sender)
}
cell.cell = reusableValueCell
self.sections[self.sections.count - 1].cells.insert(cell, at: 0)
//When i put a break point at this spot, i find that reusableValueCell is the same object as the cell that is already being used.
tableView.reloadData()
reusableValueCell.prepareForReuse()
}
When i debug it, i find that dequeueReusableCell(withIdentifier: ) returns the exact same RecordValueCell multiple times.
Here is my cellForRowAt:
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
guard let cell = self.sections[indexPath.section].cells[indexPath.row].cell else {
fatalError("error getting cell")
}
return cell
}
numberOfRowsInSection
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.sections[section].cells.count
}
First of all, you will need to set the View Controller Class that this table is contained in as the table's UITableViewDataSource
tableView.dataSource = self // view controller that contains the tableView
Create an array of strings as member of your View Controller class which contains the data for each cell:
var strings = [String]()
Then you will need to implement the following method for the UITableViewDataSource protocol:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return strings.count
}
You should also be dequeueing the cells in your cellForRowAt method like so:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: yourIdentifier) as! YourCellClass
cell.textLabel = strings[indexPath.row]
return cell
}
Then whenever the user enters into the textField, their input will be appended to this array:
let input = textField.text
strings.append(input)
tableView.reloadData()
Once the data is reloaded, the cell will be added to the table automatically since the number of rows are defined by the String array's length and the label is set in the cellForRowAt method.
This feature is very easy to implement if you will do in a good way.
First, you have to create two TableCell. First to give the option to add a record with plus button and second for entering a value with textfield. Now always return first cell (AddRecordTableCell) in the last row in tableView, and return the number of rows according to entered values like
return totalValues.count + 1
I have spent days on resolving this issue and after trying much I am asking a question here. I am using a custom UITableViewCell and that cell contains UITextFields. On adding new cells to the table view, the table view behaves abnormal like it duplicates the cell and when I try to edit the textfield of new cell, the textfield of previous cel gets edited too.
The behavior of duplication is as follows: 1st cell is duplicated for 3rd cell. I don't know this is due to reusability of cells but could anyone tell me about the efficient solution?
I am attaching the screenshot of UITableViewCell.
The code for cellForRow is as follows:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell : Product_PriceTableViewCell = tableView.dequeueReusableCell(withIdentifier: "product_priceCell") as! Product_PriceTableViewCell
cell.dropDownViewProducts.index = indexPath.row
cell.txtDescription.index = indexPath.row
cell.tfPrice.index = indexPath.row
cell.dropDownQty.index = indexPath.row
cell.tfTotalPrice_Euro.index = indexPath.row
cell.tfTotalPrice_IDR.index = indexPath.row
cell.dropDownViewTotalDiscount.index = indexPath.row
cell.dropDownViewDeposit.index = indexPath.row
cell.tfTotalDeposit_Euro.index = indexPath.row
cell.tfRemaingAfterDeposit_IDR.index = indexPath.row
return cell
}
The issue is the cell is being reused by the UITableView, which is what you want to happen for good scrolling performance.
You should update the data source that supports each row in the table to hold the text the user inputs in the field.
Then have the text field's text property assigned from your data source in cellForRowAt.
In other words, the UITableViewCell is the same instance each time you see it on the screen, and so is the UITextField and therefore so is it's text property. Which means it needs to be assigned it's correct text value each time cellForRowAt is called.
I'm unsure of your code so I have provided an example of how I would do something like what you want:
class MyCell: UITableViewCell {
#IBOutlet weak var inputField: UITextField!
}
class ViewController: UIViewController {
#IBOutlet weak var table: UITableView!
var items = [String]()
fileprivate func setupItems() {
items = ["Duck",
"Cow",
"Deer",
"Potato"
]
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
setupItems()
}
}
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// the # of rows will equal the # of items
return items.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// we use the cell's indexPath.row to
// to get the item in the array's text
// and use it as the cell's input field text
guard let cell = tableView.dequeueReusableCell(withIdentifier: "myCell") as? MyCell else {
return UITableViewCell()
}
// now even if the cell is the same instance
// it's field's text is assigned each time
cell.inputField.text = items[indexPath.row]
// Use the tag on UITextField
// to track the indexPath.row that
// it's current being presented for
cell.inputField.tag = indexPath.row
// become the field's delegate
cell.inputField.delegate = self
return cell
}
}
extension ViewController: UITextFieldDelegate {
// or whatever method(s) matches the app's
// input style for this view
func textFieldDidEndEditing(_ textField: UITextField) {
guard let text = textField.text else {
return // nothing to update
}
// use the field's tag
// to update the correct element
items[textField.tag] = text
}
}
I suggest to do the following
class Product_PriceTableViewCell: UITableViewCell {
var indexRow: Int = -1
func configureCell(index: Int) {
cell.dropDownViewProducts.clean()
...
cell.tfRemaingAfterDeposit_IDR.clean()
}
}
where clean is the function to empty de view (depend on the type)
Then in the delegate:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell : Product_PriceTableViewCell = tableView.dequeueReusableCell(withIdentifier: "product_priceCell") as! Product_PriceTableViewCell
cell.configureCell(row: indexPath.row)
return cell
}
As #thefredelement pointed out when the cell is not in the view frame, it is not created. Only when the view is going to appear, it tries to reuse an instance of the cell and as the first is available, the table view uses it but does not reinitialize it. So you have to make sure to clean the data
The rest of the answer is for better coding.
I'm trying to combine a CollectionViewwith a TableView, so fare everything works except one problem, which I cant fix myself.
I have to load some data in the CollectionViews which are sorted with the header of the TableViewCell where the CollectionView is inside. For some reason, every time I start the app, the first three TableViewCells are identical. If I scroll a little bit vertically, they change to the right Data.
But it can also happen that while using it sometimes displays the same Data as in on TableViewCell another TableViewCell, here again the problem is solved if I scroll a little.
I think the problem are the reusableCells but I cant find the mistake myself. I tried to insert a colletionView.reloadData() and to set the cells to nil before reusing, sadly this didn`t work.
My TableViewController
import UIKit
import RealmSwift
import Alamofire
import SwiftyJSON
let myGroupLive = DispatchGroup()
let myGroupCommunity = DispatchGroup()
var channelTitle=""
class HomeVTwoTableViewController: UITableViewController {
var headers = ["LIVE","Channel1", "Channel2", "Channel3", "Channel4", "Channel5", "Channel6"]
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear(_ animated: Bool) {
self.navigationController?.navigationBar.isTranslucent = false
DataController().fetchDataLive(mode: "get")
DataController().fetchDataCommunity(mode: "get")
}
//MARK: Custom Tableview Headers
override func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return headers[section]
}
//MARK: DataSource Methods
override func numberOfSections(in tableView: UITableView) -> Int {
return headers.count
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
//Choosing the responsible PrototypCell for the Sections
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0 {
let cell = tableView.dequeueReusableCell(withIdentifier: "cellBig", for: indexPath) as! HomeVTwoTableViewCell
print("TableViewreloadMain")
cell.collectionView.reloadData()
return cell
}
else if indexPath.section >= 1 {
// getting header Titel for reuse in cell
channelTitle = self.tableView(tableView, titleForHeaderInSection: indexPath.section)!
let cell = tableView.dequeueReusableCell(withIdentifier: "cellSmall", for: indexPath) as! HomeVTwoTableViewCellSmall
// anti Duplicate protection
cell.collectionView.reloadData()
return cell
}
else {
channelTitle = self.tableView(tableView, titleForHeaderInSection: indexPath.section)!
let cell = tableView.dequeueReusableCell(withIdentifier: "cellSmall", for: indexPath) as! HomeVTwoTableViewCellSmall
// anti Duplicate protection
cell.collectionView.reloadData()
return cell
}
}
}
}
My TableViewCell with `CollectionView
import UIKit
import RealmSwift
var communities: Results<Community>?
class HomeVTwoTableViewCellSmall: UITableViewCell{
//serves as a translator from ChannelName to the ChannelId
var channelOverview: [String:String] = ["Channel1": "399", "Channel2": "401", "Channel3": "360", "Channel4": "322", "Channel5": "385", "Channel6": "4"]
//Initiaize the CellChannel Container
var cellChannel: Results<Community>!
//Initialize the translated ChannelId
var channelId: String = ""
#IBOutlet weak var collectionView: UICollectionView!
}
extension HomeVTwoTableViewCellSmall: UICollectionViewDataSource,UICollectionViewDelegate {
//MARK: Datasource Methods
func numberOfSections(in collectionView: UICollectionView) -> Int
{
return 1
}
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int
{
return (cellChannel.count)
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
{
guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "collectionCellSmall", for: indexPath) as? HomeVTwoCollectionViewCellSmall else
{
fatalError("Cell has wrong type")
}
//removes the old image and Titel
cell.imageView.image = nil
cell.titleLbl.text = nil
//inserting the channel specific data
let url : String = (cellChannel[indexPath.row].pictureId)
let name :String = (cellChannel[indexPath.row].communityName)
cell.titleLbl.text = name
cell.imageView.downloadedFrom(link :"link")
return cell
}
//MARK: Delegate Methods
override func layoutSubviews() {
myGroupCommunity.notify(queue: DispatchQueue.main, execute: {
let realm = try! Realm()
//Getting the ChannelId from Dictionary
self.channelId = self.channelOverview[channelTitle]!
//load data from Realm into variables
self.cellChannel = realm.objects(Community.self).filter("channelId = \(String(describing: self.channelId)) ")
self.collectionView.dataSource = self
self.collectionView.delegate = self
print("collectionView layout Subviews")
self.collectionView.reloadData()
})
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
selectedCommunity = (cellChannel[indexPath.row].communityId)
let home = HomeViewController()
home.showCommunityDetail()
}
}
Thanks in advance.
tl;dr make channelTitle a variable on your cell and not a global variable. Also, clear it, and your other cell variables, on prepareForReuse
I may be mistaken here, but are you setting the channelTitle on the cells once you create them? As I see it, in your viewController you create cells based on your headers, and for each cell you set TableViewController's channelTitle to be the title at the given section.
If this is the case, then the TableViewCell actually isn't receiving any information about what it should be loading before you call reloadData().
In general, I would also recommend implementing prepareForReuse in your HomeVTwoTableViewCellSmall, since it will give you a chance to clean up any stale data. Likely you would want to do something like set cellChannel and channelId to empty strings or nil in that method, so when the cell is reused that old data is sticking around.
ALSO, I just reread the cell code you have, and it looks like you're doing some critical initial cell setup in layoutSubviews. That method is going to be potentially called a lot, but you really only need it to be called once (for the majority of what it does). Try this out:
override the init with reuse identifier on the cell
in that init, add self.collectionView.dataSource = self and self.collectionView.delegate = self
add a didSet on channelTitle
set channelTitle in the viewController
So the code would look like:
var channelTitle: String = "" {
didSet {
self.channelId = self.channelOverview[channelTitle]!
self.cellChannel = realm.objects(Community.self).filter("channelId = \(String(describing: self.channelId)) ")
self.collectionView.reloadData()
}
}
This way you're only reloading your data when the cell is updated with a new channel, rather than every layout of the cell's views.
Sorry... one more addition. I wasn't aware of how your channelTitle was actually being passed. As I see it, you're using channelTitle as a global variable rather than a local one. Don't do that! remove channelTitle from where it is currently before implementing the code above. You'll see some errors, because you're setting it in the ViewController and accessing it in the cell. What you want is to set the channelTitle on the cell from the ViewController (as I outlined above). That also explains why you were seeing the same data across all three cells. Basically you had set only ONE channelTitle and all three cells were looking to that global value to fetch their data.
Hope that helps a little!
(also, you should be able to remove your else if block in the cellForRowAtIndexPath method, since the else block that follows it covers the same code. You can also delete your viewDidLoad, since it isn't doing anything, and you should, as a rule, see if you can get rid of any !'s because they're unsafe. Use ? or guard or if let instead)