I am trying to delete row from UITableView by using trailingSwipeActionsConfigurationForRowAt function.
The row gets deleted and disappears. This part is ok.
But next rows that are coming to the screen or when I swipe down the same amount as the rows been deleted are not even loaded on the tableView.
![img1]https://poirot.deus4.com/photo_2019-06-12_16-44-01.jpg
![img2]https://poirot.deus4.com/photo_2019-06-12_16-43-56.jpg
![img3]https://poirot.deus4.com/photo_2019-06-12_16-43-49.jpg
![img4]https://poirot.deus4.com/photo_2019-06-12_16-43-38.jpg
[video]https://poirot.deus4.com/RPReplay_Final1560345600.mp4
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return filteredProducts.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: .cellID, for: indexPath) as! ProductTableCell
cell.backgroundColor = .red
return cell
}
override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
let hide = UIContextualAction(style: .destructive, title: "Hide") { action, view, completion in
self.filteredProducts.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .automatic)
completion(true)
}
hide.image = #imageLiteral(resourceName: "hdie_product")
hide.backgroundColor = .midGrey
let conf = UISwipeActionsConfiguration(actions: [hide])
return conf
}
The code you showed obviously works, thus the problem is elsewhere.
Without other code I suspect that the problem is because table view cells are re-used: When you scroll your table view, some cells are scrolled out of view and can be reused. Cells that are scrolled in are either re-used cells or new cells.
In any case, the table view datasource function tableView(_:cellForRowAt:) must be used to configure the displayed cells.
It seems too me that you do not configure the cells in tableView(_:cellForRowAt:).
If so, re-used cells look as the were when they have been scrolled out, but new cells are simply blank.
So I suggest to check if you really configure all the cells in tableView(_:cellForRowAt:) correctly.
The issue was that I did not call super.prepareForReuse() inside TablewViewCell
override func prepareForReuse() {
super.prepareForReuse() // this was missing
}
Related
I am using a UITableView and what I am doing is I am changing the color of the cell when I tap on the cell using didSelectRow function of UITableView at cellForRowAt. The thing which is bothering me is when I scroll down or scroll up, those cells whom I changed the color before were changed to other cells. Here is my code:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = myTableView.dequeueReusableCell(withIdentifier: "TasksTableViewCell") as! TasksTableViewCell
cell.backView.backgroundColor = .white
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let cell = myTableView.cellForRow(at: indexPath) as! TasksTableViewCell
cell.backView.backgroundColor = UIColor(named: "primaryViewColor")
}
Does anyone knows why this happens? Does anyone has a solution that when only those cells changes color whom I tap on, and when I scroll down or move up only those cells have the other color?
cellForRowAt will be called every time that cell is displayed.
you need selected list to save selected index.
var listSelected: [Int] = []
and
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "TasksTableViewCell") as! TasksTableViewCell
cell.backView.backgroundColor = listSelected.contains(indexPath.row) ? UIColor(named: "primaryViewColor") : .white
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
if listSelected.contains(indexPath.row) {
listSelected = listSelected.filter{$0 != indexPath.row}
} else {
listSelected.append(indexPath.row)
}
tableView.reloadRows(at: [indexPath], with: .automatic)
}
I encountered do you see the problem many times. Even if using and iVar can solve the problem, You are mixing "Controller" logic and "Model" logic.
I usually prefer to move "selection" state inside the model.
Suppose You have a class "Contact" you use to fill cell data (usual MVC pattern)
I add:
class contact{
..
var selected = false
}
AND in TV delegation method I use to apply selection, OR better I use a custom selection method in a custom cell (for example to see a √ element in cell)
As a bonus multiple selection come for free, and you can also save current selections for next run :)
So as I understand you select a cell and after that other cells look like they are selected?
If so I think this is happening because you change the background color of the cell and tableViews and collectionViews are reusing the cells, basically keeping the background you changed behind.
TableViewCells are reused as soon as they leave the visible area.
This means that a cell whose background you have colored will be deleted from the view hierarchy as soon as it is scrolled up or down. If the corresponding row is scrolled in again, the function cellForRowAt is called again for this IndexPath and the cell gets a white background.
The easiest is to save the IndexPaths of the selected cells and check in the cellForRowAt function if the current cell has to be selected.
Add the following var to the viewController class:
var selectedIndexPaths = Set<IndexPath>()
and modify the tableView delegate methods:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = myTableView.dequeueReusableCell(withIdentifier: "TasksTableViewCell") as! TasksTableViewCell
cell.backView.backgroundColor = (selectedIndexPaths.contains(indexPath) ? UIColor(named: "primaryViewColor") : .white)
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
{
if selectedIndexPaths.contains(indexPath)
{
selectedIndexPaths.remove(indexPath)
}
else
{
selectedIndexPaths.insert(indexPath)
}
tableView.reloadRows(at: [indexPath], with: .none)
}
You can use
step 1: create model
class DemoModel {
var isSelected: Bool = false
var color: UIColor = .While
}
step 2: and in tableview
var listDemo: [DemoModel] = [DemoModel(),...]
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = myTableView.dequeueReusableCell(withIdentifier:
"TasksTableViewCell") as! TasksTableViewCell
var obj = listDemo[indexPath.row]
cell.backView.backgroundColor = obj.color
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
var obj = listDemo[indexPath.row]
obj.color = UIColor(named: "primaryViewColor")
tableView.reloadRows(at: [indexPath], with: .automatic)
}
I want to delete all the UITableviewCells in my Tableview by tapping a button
UITableView DataSource Methods
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return UserList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "FriendAddCell" , for: indexPath) as! AddFriendLTableViewCell
cell.lb_Email.text = UserList[indexPath.row].userEmail
let imageUrl = URL(string: UserList[indexPath.row].imageUrl)
cell.img_Avatar.loadImageUrl(url: imageUrl!)
return cell
}
My Button Function
#IBAction func btn_NewAddUser(_ sender: Any) {
UserList.removeAll()
table_SearchFirends.reloadData()
}
the cells I tried to delete still exist when I add a new cell
How can I delete all the cells by pressing the button?
How can I make the tableView as if there were no rows created?
How I can understand your problem that you see empty lines with separator lines on bottom.
Make this for remove extra lines:
tableView.tableFooterView = UIView()
And some advise - use camelCase style in Swift.
I am showing a UITableView which is driven by RxRealmDataSources.
I need to perform some actions when a row in the table gets deleted.
Is there a way such that whenever a row gets deleted from the table, a function gets called with the indexpath of the deleted row?
Edit -
The UI of a cell of the UITableView in my app depends on 2 things -
A data object that is fetched from the realm db ( info )
The index position of the row
Whenever, a cell gets deleted, I need to update the UI of its next cell.
If the only way the db ever got updated was by the direct action of the user, then I could have used func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) method to get the indexPath of the cell that should be deleted and update the UI of the next cell.
However, the db is synced to cloud and the db is binded to the table view so that I do not have control on when cells gets added or deleted. It is for this reason, I wanted to know if there is a way to know when a cell is removed from UITableView
Due to the reusability of cells in UITableView, cells are not actually deleted until the table itself is deallocated.
I might assume that by 'deleting' cell you mean cell disappearing from the screen. In this case the following function of UITableViewDelegate might help you (called when the cell is not visible any more):
func tableView(_ tableView: UITableView, didEndDisplaying cell: UITableViewCell, forRowAt indexPath: IndexPath)
In a comment you said:
By 'deleting', I mean when the cell is removed from the tableview like when we swipe the cell to the left to remove it.
Since you tagged RxSwift, the solution is to use itemDeleted as in:
tableView.rx.itemDeleted
.subscribe(onNext: { print("delete item at index path \($0) from your model.")})
.disposed(by: bag)
If you aren't looking for an Rx solution, then your question is a dup of:
Add swipe to delete UITableViewCell
I was able to solve this by subclassing the UITableView class and overriding the func deleteRows(at indexPaths: [IndexPath], with animation: UITableView.RowAnimation) method.
You have to implement 1 delegate method of UITableView.
trailingSwipeActionsConfigurationForRowAt
It's easy to implement. This delegate method will be called twice, one when you swipe and again when you press to delete a row.
`enter code here`
func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
let config = UISwipeActionsConfiguration(actions: [makeDeleteContextualAction(forRowAt: indexPath)])
config.performsFirstActionWithFullSwipe = true
return config
}
private func makeDeleteContextualAction(forRowAt indexpath:IndexPath) -> UIContextualAction {
let deleteAction = UIContextualAction(style: .destructive, title: LocalizableConstants.constLS_global_delete()) { (action, swipeButtonView, completion) in
let product = self.products[indexpath.row]
if let quantity = product.vo_quantity(), let amount = product.vo_priceFide() {
self.totalProducts -= Int(truncating: quantity)
self.totalAmount -= amount.doubleValue * quantity.doubleValue
}
DispatchQueue.main.async {
self.lbBasketNumber.text = String(self.totalProducts)
self.lbTotalAmount.text = String(self.totalAmount)
}
self.products.remove(at: indexpath.row)
self.tableView.deleteRows(at: [indexpath], with: .fade)
if #available(iOS 13.0, *) {
action.image = ImagesConstants.constIMG_XCA_mini_icon_red_trash()
action.image?.withTintColor(ConstantsColor.const_COLOR_RED())
action.backgroundColor = ConstantsColor.const_COLOR_WHITE()
} else {
action.title = LocalizableConstants.constLS_global_delete()
}
completion(true)
}
return deleteAction
}
So every time I scroll my tableView it reloads data which I find ridiculous since it makes no sense to reload data as it hasn't been changed.
So I setup my tableView as follows:
func numberOfSections(in tableView: UITableView) -> Int {
return self.numberOfElements
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 6
}
My cells are really custom and they require spacing between them. I couldn't add an extra View to my cell to fake that spacing because I have corner radius and it just ruins it. So I had to make each row = a section and set the spacing as a section height.
My cell has a dynamic height and can change it's height when I click "more" button, so the cell extends a little.
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if self.segmentedControl.selectedSegmentIndex == 0 {
if self.isCellSelectedAt[indexPath.section] {
return self.fullCellHeight
} else {
return self.shortCellHeight
}
} else {
return 148
}
}
And here's how I setup my cell:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell = UITableViewCell()
if self.segmentedControl.selectedSegmentIndex == 0 {
cell = tableView.dequeueReusableCell(withIdentifier: String.className(CurrentDocCell.self)) as! CurrentDocCell
(cell as! CurrentDocCell).delegate = self
(cell as! CurrentDocCell).ID = indexPath.section
} else {
cell = tableView.dequeueReusableCell(withIdentifier: String.className(PromissoryDocCell.self)) as! PromissoryDocCell
}
return cell
}
So I have a segmentedControl by switching which I can present either one cell of a certain height or the other one which is expandable.
In my viewDidLoad I have only these settings for tableView:
self.tableView.registerCellNib(CurrentDocCell.self)
self.tableView.registerCellNib(PromissoryDocCell.self)
And to expand the cell I have this delegate method:
func showDetails(at ID: Int) {
self.tableView.beginUpdates()
self.isCellSelectedAt[ID] = !self.isCellSelectedAt[ID]
self.tableView.endUpdates()
}
I set a breakpoint at cellForRowAt tableView method and it indeed gets called every time I scroll my tableView.
Any ideas? I feel like doing another approach to make cell spacing might fix this issue.
A UITableView only loads that part of its datasource which gets currently displayed. This dramatically increases the performance of the tableview, especially if the datasource contains thousands of records.
So it is the normal behaviour to reload the needed parts of the datasource when you scroll.
Requirement :
I have a list of UITableviewCell loaded from a nib that I'm presenting on UITableview. The first time I open the UIViewController all cells are shown correctly and work as expected.
Issue :
If I navigate back to the parent and then open the UIViewController again the UITableviewCell are 'invisible'. I say invisible because with a breakpoint in cellForRowAt I can see that the table view does load all cells and the cells are valid.
Code :
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 13
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 40
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = (project?.sliderData.sliders[indexPath.row].view)! as UITableViewCell
print(cell.contentView.subviews.count)
if let left = cell.viewWithTag(2) as? UILabel {
left.text = "left"
}
if let middle = cell.viewWithTag(3) as? UILabel {
middle.text = "middle"
}
if let right = cell.viewWithTag(4) as? UILabel {
right.text = "right"
}
return cell
}
Screen Shot Image
Expected observation :
I was thinking that maybe the subviews of the cells get released because I don't have any bindings to them in IB. To test this I'm printing the count of subviews and writing some text to the subview labels. And everything seems to go fine, the cells are loaded and the labels are there but the cells just don't show up.
But then, if I scroll the TableView up and down a little to get some cells updated those cells do appear at the top and bottom of the view as shown in the pic.
You need to call dequeueReusableCell(withIdentifier: "cell") inside your code then will show your table cell. It will reuse cell for your all numbers of row data content.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! UITableViewCell
return cell
}
More Details : How to create uitableview with multiple sections in iOS Swift.
Did not find reason why the tableView behaves the way it does so I solved the issue by dequeueing default cells. The views provided by the slider objects are added as subviews to the dequeued cells. Now the subviews can of course be any UIViews.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCell(withIdentifier: "sliderCell")
if cell == nil {
cell = UITableViewCell.init(style: .default, reuseIdentifier: "sliderCell")
}
cell?.addSubview((project?.sliderData.sliders[indexPath.row].view)!)
return cell!
}