After any row is deleted by deleteRows(at:with:) from my Table View, I cannot get textfield in a reusable custom cell to get focus by becomeFirstResponder() (which is called after insertRows(at:with:) is called). becomeFirstResponder() is always called within cellForRow(at:).
This problem always starts occuring after a row is deleted from the table view by deleteRows(at:with:). Before any row is deleted there is no problem, becomeFirstResponder() can give focus to the textfield as intended.
I made some tests to understand why this problem occurs after a row is deleted... My tests showed an interesting difference:
Case 1: After any row is deleted (i.e. while becomeFirstResponder() returns false), textFieldShouldBeginEditing(_:) is called BEFORE cellForRow(at:) returns. textFieldDidBeginEditing(_:) is never called.
Case 2: On the other hand, before any row is deleted (i.e. while becomeFirstResponder() returns true), textFieldShouldBeginEditing(_:) is called AFTER cellForRow(at:) returns. textFieldDidBeginEditing(_:) is called immediately after textFieldShouldBeginEditing(_:), as expected.
The problem might be related to this difference, but I couldn't solve this mystery after trying & researching for many hours.
In a related Q&A, it is suggested not to reload tableView from within textFieldDidEndEditing(). In my case, deleteRows(at:with:) method are sometimes called from within textFieldDidEndEditing() and sometimes called from tableView(_:commit:forRowAt:) (i.e. by swiping to left). So this does not explain my problem. Another related Q&A might be this one.
getFocus() in CustomCell's class, called from cellForRow(at:) in TableViewController:
func getFocus() {
if let itemTextField = itemTextField {
itemTextField.delegate = self
itemTextField.isUserInteractionEnabled = true
itemTextField.becomeFirstResponder()
}
}
cellForRow(at:):
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let item = items[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomCell
cell.setCell(item: item)
cell.delegate = self
if insertingRow == true {
if isTempItem(item: item, indexPath: indexPath) {
cell.getFocus()
} else {
print("isTempItem returned false, no need to give focus.")
}
}
return cell
}
Don't call getFocus in cellForRowAt, Insteed of when you insert new row, You can scroll to new row and call getFocus in willDisplayCell.
Hope to help you.
Related
I am changing the numberOfLines attribute on a label that lives in a custom UITableViewCell when the cell is tapped. However, this is not reflected in the UI until the second tap. The cell is configured as a prototype cell in the table view to initially have 2 lines.
Interestingly enough, when I print out the numberOfLines value before and after my tapped() function runs, the values start off different, and then synchronize - after the first tap, I see 2 lines before the function runs, then 0 lines after the function runs. However, after subsequent taps, I see the same value before and after my function, which makes it seem like it's not doing anything, even though the UI does stretch and shrink the cell, and the numberOfLines value is changed for the next time the didSelectRowAtIndexPath function runs.
I'm only seeing this behavior with tableView.reloadRows(). If I do a full update with tableView.reloadData(), the cell appropriately grows and collapses the first time it is tapped. However, this feels a bit ham-fisted and doesn't animate nicely like reloadRows() does.
TableView Implementation
func tableView(_ tableView: UITableView,
didSelectRowAt indexPath: IndexPath) {
guard let cell = tableView.cellForRow(at: indexPath) as? ReviewTableViewCell
else { return }
let data = tableData[indexPath.row]
print("old number of lines: \(cell.detailLabel.numberOfLines)")
//data.isOpen is set to false initially
cell.tapped(data.isOpen)
tableData[indexPath.row].isOpen = !data.isOpen
tableView.reloadRows(at: [indexPath], with: .fade)
print("old number of lines: \(cell.detailLabel.numberOfLines)")
// tableView.reloadData()
}
Custom Table View Cell method
func tapped(_ isOpen: Bool) {
if !isOpen {
detailLabel.numberOfLines = 0 }
else {
detailLabel.numberOfLines = 2 }
}
I am expecting this code to expand the cell once it is reloaded with tableView.reloadRows() if the numberOfLines is set to 0 and collapse the cell when it is set to 2. This does work, but only after tapping the cell two+ times. This should work with the first tap as well.
Here is a link of a gif that shows the issue: https://imgur.com/a/qe2uAXj
Here is a sample project that is similar to what's going on in my app: https://github.com/imattice/CellLabelExample
Just to be clear, to get this trick work UILabel generally must be constrained on each side to it's superview, in this way when it changes its intrinsicContentSize is able to push each side to accomodate the text.
Saying that, try to wrap the tapped method with those two methods:
tableView.beginUpdates()
if !isOpen {
detailLabel.numberOfLines = 0
}
else {
detailLabel.numberOfLines = 2
}
tableView.endUpdates()
Of course tableview must be set to automatic size:
tableView.estimatedRowHeight = <#What you want#>
tableView.rowHeight = UITableView.automaticDimension
I was able to work out what was going on. The problem is in two parts.
The first part is calling reloadRows(). This method is swapping out the cells with a new cell rather than updating the cell that already exists. Therefore, I'm changing the number of lines on that hidden swap cell rather than the cell that is in view. This behavior is mentioned in the docs:
Reloading a row causes the table view to ask its data source for a new cell for that row. The table animates that new cell in as it animates the old row out.
Additionally, I'm using structs as the data model for tracking the open status of the cell. In Swift, structs are copy-on-write, which means that if a value is changed on that struct, a new struct is created rather than changing the value of that struct I'm pointing to. This means the line tableData[indexPath.row].isOpen = !data.isOpen doesn't do anything useful - we look at the tableData struct at the index path, get it's isOpen value, copy a new struct and change that new struct's isOpen value, and then throw it out because the new struct is not assigned anywhere.
The solution is to not use the reloadRows() method and to either use
A) a class for the data object
B) replace the data at indexPath.row to the copied struct
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
guard let cell = tableView.cellForRow(at: indexPath) as? CustomCell else { return }
var data = tableData[indexPath.row]
tableView.beginUpdates()
cell.tapped(isOpen: data.isOpen)
data.isOpen = !data.isOpen
tableData[indexPath.row] = data
tableView.endUpdates()
}
I have a table view with custom cells. They are quite tall, so only one cell is completely visible on the screen and maybe, depending on the position of that cell, the top 25% of the second one. These cells represent dummy items, which have names. Inside of each cell there is a button. When tapped for the first time, it shows a small UIView inside the cell and adds the item to an array, and being tapped for the second time, hides it and removes the item. The part of adding and removing items works fine, however, there is a problem related to showing and hiding views because of the fact that cells are reused in a UITableView
When I add the view, for example, on the first cell, on the third or fourth cell (after the cell is reused) I can still see that view.
To prevent this I've tried to loop the array of items and check their names against each cell's name label's text. I know that this method is not very efficient (what if there are thousands of them?), but I've tried it anyway.
Here is the simple code for it (checkedItems is the array of items, for which the view should be visible):
if let cell = cell as? ItemTableViewCell {
if cell.itemNameLabel.text != nil {
for item in checkedItems {
if cell.itemNameLabel.text == item.name {
cell.checkedView.isHidden = false
} else {
cell.checkedView.isHidden = true
}
}
}
This code works fine at a first glance, but after digging a bit deeper some issues show up. When I tap on the first cell to show the view, and then I tap on the second one to show the view on it, too, it works fine. However, when I tap, for example, on the first one and the third one, the view on the first cell disappears, but the item is still in the array. I suspect, that the reason is still the fact of cells being reused because, again, cells are quite big in their height so the first cell is not visible when the third one is. I've tried to use the code above inside tableView(_:,cellForRow:) and tableView(_:,willDisplay:,forRowAt:) methods but the result is the same.
So, here is the problem: I need to find an EFFICIENT way to check cells and show the view ONLY inside of those which items are in the checkedItems array.
EDITED
Here is how the cell looks with and without the view (the purple circle is the button, and the view is the orange one)
And here is the code for the button:
protocol ItemTableViewCellDelegate: class {
func cellCheckButtonDidTapped(cell: ExampleTableViewCell)
}
Inside the cell:
#IBAction func checkButtonTapped(_ sender: UIButton) {
delegate?.cellCheckButtonDidTapped(cell: self)
}
Inside the view controller (NOTE: the code here just shows and hides the view. The purpose of the code is to show how the button interacts with the table view):
extension ItemCellsTableViewController: ItemTableViewCellDelegate {
func cellCheckButtonDidTapped(cell: ItemTableViewCell) {
UIView.transition(with: cell.checkedView, duration: 0.1, options: .transitionCrossDissolve, animations: {
cell.checkedView.isHidden = !cell.checkedView.isHidden
}, completion: nil)
}
EDITED 2
Here is the full code of tableView(_ cellForRowAt:) method (I've deleted the looping part from the question to make it clear what was the method initially doing). The item property on the cell just sets the name of the item (itemNameLabel's text).
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCell(withIdentifier:
ItemTableViewCell.identifier, for: indexPath) as? ItemTableViewCell{
cell.item = items[indexPath.row]
cell.delegate = self
cell.selectionStyle = .none
return cell
}
return UITableViewCell()
}
I've tried the solution, suggested here, but this doesn't work for me.
If you have faced with such a problem and know how to solve it, I would appreciate your help and suggestions very much.
Try this.
Define Globally : var arrIndexPaths = NSMutableArray()
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 30
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell:TableViewCell = self.tblVW.dequeueReusableCell(withIdentifier: "TableViewCell", for: indexPath) as! TableViewCell
cell.textLabel?.text = String.init(format: "Row %d", indexPath.row)
cell.btn.tag = indexPath.row
cell.btn.addTarget(self, action: #selector(btnTapped), for: .touchUpInside)
if arrIndexPaths.contains(indexPath) {
cell.backgroundColor = UIColor.red.withAlphaComponent(0.2)
}
else {
cell.backgroundColor = UIColor.white
}
return cell;
}
#IBAction func btnTapped(_ sender: UIButton) {
let selectedIndexPath = NSIndexPath.init(row: sender.tag, section: 0)
// IF YOU WANT TO SHOW SINGLE SELECTED VIEW AT A TIME THAN TRY THIS
arrIndexPaths.removeAllObjects()
arrIndexPaths.add(selectedIndexPath)
self.tblVW.reloadData()
}
I would keep the state of your individual cells as part of the modeldata that lies behind every cell.
I assume that you have an array of model objects that you use when populating you tableview in tableView(_:,cellForRow:). That model is populated from some backend service that gives you some JSON, which you then map to model objects once the view is loaded the first time.
If you add a property to your model objects indicating whether the cell has been pressed or not, you can use that when you populate your cell.
You should probably create a "wrapper object" containing your original JSON data and then a variable containing the state, lets call it isHidden. You can either use a Bool value or you can use an enum if you're up for it. Here is an example using just a Bool
struct MyWrappedModel {
var yourJSONDataHere: YourModelType
var isHidden = true
init(yourJSONModel: YourModelType) {
self.yourJSONDataHere = yourJSONModel
}
}
In any case, when your cell is tapped (in didSelectRow) you would:
find the right MyWrappedModel object in your array of wrapped modeldata objects based on the indexpath
toggle the isHidden value on that
reload your affected row in the table view with reloadRows(at:with:)
In tableView(_:,cellForRow:) you can now check if isHidden and do some rendering based on that:
...//fetch the modelObject for the current IndexPath
cell.checkedView.isHidden = modelObject.isHidden
Futhermore, know that the method prepareForReuse exists on a UITableViewCell. This method is called when ever a cell is just about to be recycled. That means that you can use that as a last resort to "initialize" your table view cells before they are rendered. So in your case you could hide the checkedView as a default.
If you do this, you no longer have to use an array to keep track of which cells have been tapped. The modeldata it self knows what state it holds and is completely independent of cell positions and recycling.
Hope this helps.
I have a tableView where I want to display different Cells depending on what a variable seguedDisplayMonth is set to. Is this possible and if so can I get any hint on how to do this? I've tried the following but it doesn't seem to work.
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Income Cell", forIndexPath: indexPath)
let income = myIncomeArray[indexPath.row]
if seguedDisplayMonth == "All" {
var text = "\(income.money) kr"
cell.textLabel?.text = text
cell.detailTextLabel?.text = income.name
}
return cell
}
I also thought that maybe I need to reload the data after changing the seguedDisplayMonth which gets changed from a different tableView and through a segue.
Call mcTableSwag.reloadData() once seguedDisplayMonth is changed. (Likely call it in the function that actually changes seguedDisplayMonth.
Alternatively you could reload certian cells with some method like reloadVisibleCellsAtIndexPath(...) (Im not sure what it is called exactly, but it should be on the Apple UITableView documentation.
I managed to fix it finally. I will explain how I did it incase anyone runs into the same problem.
I implemented another array myVisibleIncomeArray.
In viewDidLoad() I called a function which does the following:
for inc in myIncomeArray {
if self.monthLabel.text == "All" {
self.myVisibleIncomeArray.append(inc)
totalSum += inc.money
print("Added to myVisible")
}
}
Then I reloadData() and use myVisibleIncomeArray for the other functions.
Not sure if it was the smartest fix, but it's a fix nonetheless.
I am using xCode 7 beta and Swift to implement a tableview with MGSwipeTableCells. I am doing this because I need to have a swipe button on both the left and right of each cell. Both of these buttons needs to remove the cell from the tableview.
I tried doing this by using the convenience callback method when adding the buttons to the cells:
// Layout table view cell
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCellWithIdentifier("newsFeedCell", forIndexPath: indexPath) as! NewsFeedCell
cell.layoutIfNeeded()
// Add a remove button to the cell
let removeButton = MGSwipeButton(title: "Remove", backgroundColor: color.removeButtonColor, callback: {
(sender: MGSwipeTableCell!) -> Bool in
// FIXME: UPDATE model
self.numberOfEvents--
self.tableView.deleteSections(NSIndexSet(index: indexPath.section), withRowAnimation: UITableViewRowAnimation.Fade)
return true
})
cell.leftButtons = [removeButton]
However, once I delete the first cell, all the indices are thrown off and the callback now deletes an incorrect cell. That is, if I delete cell_0, cell_1 now becomes the first 0th in the table. However, the callback for the buttons associated with cell_1 delete the cell with index 1 even though it is actually now the 0th cell in the table.
I tried to implement the MGSwipeTableCell delegate methods, but to no avail. None of these methods were ever called in the execution of my code. How should I fix this problem? Will implementing the delegate solve this issue? If, so would it be possible to provide an example? If not, can you please suggest an alternate way to have tableview cells with swipe buttons on both sides that can delete said cells?
You can also do something like this to get the correct indexPath:
let removeButton = MGSwipeButton(title: "Remove", backgroundColor: color.removeButtonColor, callback: {
(sender: MGSwipeTableCell!) -> Bool in
let indexPath = self.tableView.indexPathForCell(sender)
self.tableView.deleteSections(NSIndexSet(index: indexPath.section), withRowAnimation: UITableViewRowAnimation.Fade)
return true
})
Using the delegate methods will allow for cleaner button creation and table cell removal, because the buttons will only be created for the cell when it is swiped (saves memory) and you can capture a weak reference to the 'sender' (an MGTableViewCell, or custom type) in the handler, from which you can then get the index path. Follow their example on Github:
MGSwipeTableCell/demo/MailAppDemo/MailAppDemo/MailViewController.m
Then in your cellForRowAtIndexPath, be sure to set the cell's delegate to 'self.' It looks like you're missing this, and it should fix your problem with delegate methods.
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let reuseIdentifier = "cell"
let cell = self.table.dequeueReusableCellWithIdentifier(reuseIdentifier) as! MGSwipeTableCell!
cell.delegate = self
// Configure the cell
return cell
}
Happy coding!
I'm trying to create an autocompleter using iOS 8, Swift and Xcode 6.3
I have a problem that I'm trying to solve, but I gave up... I hope someone can help here. The problem is that (custom) UITableViewCell's are not displaying when the initial dataSource is empty. When adding data to datasource and reloading the tableView, the cells SHOULD display, but they don't... At least, the first time they don't... A second time, they DO... When I initialize the table with non-empty data, the problem doesn't occur. I guess something goes wrong with dequeueReusableCellWithIdentifier. In beginning, no reusable cells are found, or something. But I don't know why...
Relevant code, in ViewController.swift:
// filteredWords is a [String] with zero or more items
#IBAction func editingChanged(sender: UITextField) {
autocompleteTableView.hidden = sender.text.isEmpty
filteredWords = dataManager.getFilteredWords(sender.text)
refreshUI()
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! AutocompleteTableViewCell
cell.title.text = filteredWords[indexPath.row]
return cell
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return filteredWords.count
}
func refreshUI() {
self.autocompleteTableView.reloadData()
}
I created a sample project on github:
https://github.com/dirkpostma/swift-autocomplete
And a movie on YoutTube to show what goes wrong:
https://www.youtube.com/watch?v=ByMsy4AaHYI
Can anyone look at it and spot the bug...?
Thanks in advance!
You've accidentally hidden your cell.
Open Main.storyboard
Select Cell
Uncheck Hidden
Side note: As for why it's displaying the second time around with the cell hidden? It appears to be a bug. It should still be hidden (print cell.hidden, notice it's always true despite showing the text on the screen).
I think you need to change your code. Check out below code. It is because if you remember in Objective C you needed to check if the Cell was nil and then initialise it. The reuse identifier is usually reusing an already created cell, but on the first launch this does not work because there is no Cell to use. Your current code assumes always that the cell is created (re-used) because you are using ! in the declaration, so if you use the optional (?) it can be null and you then can create the cell
var cell = tableView.dequeueReusableCellWithIdentifier("Cell") as? AutocompleteTableViewCell
if cell == nil
{
//You should replace this with your initialisation of custom cell
cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "CELL")
}
cell.title.text = filteredWords[indexPath.row]
return cell