How to set custom UITableViewRowAction depending on IndexPath.row? - ios

I have a
tableView(UITableView)
customCell: UITableViewCell!
itemsArray: [Item]
I tried to set custom action for cell in UITableView depending on IndexPath.row.
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath)
-> [UITableViewRowAction]? {
if !(itemsArray[indexPath.row].isReadOnly) {
let editAction = UITableViewRowAction(style: .normal, title: "Edit") {
(tableViewRowAction, indexPath) in
print("Edit Item \(self.itemsArray[indexPath.row].caption)\n")
} 
return [editAction]
} else {
return []
}
}
I tried to set custom action for cell in UITableView depending on IndexPath.row:
The problem occurs with cells, which I want to be without actions (which corresponding items has .isReadOnly = true)
I tried to return nil and [] in else case and both variants has irrelevant result for swiping:
- nil – Delete action shows for items
- [] – Cell swipes a little bit, “unswipes” back an than swipes stops working in any cell

I found a solution: just use canEditRowAt method of UITableView
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return !(items[indexPath.row].isReadOnly)
}

Related

Selection of UITableViewCell Changes when Scroll down in Swift

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)
}

UITableView: how stop selection while swipe the table view cell

I have swipe to delete code here and it my custom TableViewCell I have implemented setSelected method like below ..
func tableView(_ tableView: UITableView, editingStyleForRowAt indexPath: IndexPath) -> UITableViewCell.EditingStyle {
// tableView.allowsSelectionDuringEditing = false
if tableView.indexPathForSelectedRow != nil, tableView.indexPathForSelectedRow == indexPath {
return UITableViewCell.EditingStyle.none
}
return UITableViewCell.EditingStyle.delete
}
override func setSelected(_ selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
//some code here
}
The logic will do tableview expand collapse based on selection ..but the problem here is if I swipe to delete setSelected also triggers.. not sure how to prevent that any help would be appreciated..
Try this in cellForRow
let cell = tableView.dequeueReusableCell(withIdentifier: "cell_identifier", for: indexPath)
cell.selectionStyle = UITableViewCell.SelectionStyle.none
//or this based on swift version
cell.selectionStyle = .none
return cell
I'm not sure what the appearance you are going for but this will produce the same effect.
If swipe is across the whole screen it will trigger the delete without button press.
If half swipe you can present buttons for user to choose options.
Half swipe (Shows options):
Full swipe (Triggers delete button):
Try adding these two tableView delegate methods for a swipe to delete
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
// Determine which rows should be editable
return true
}
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath:
IndexPath) -> [UITableViewRowAction]? {
let button1 = UITableViewRowAction(style: .default, title: "Delete") {
action, indexPath in
print("delete pressed")
// Consider alert to confirm that it was intentionally deleted
}
button1.backgroundColor = UIColor.red
// Create any buttons you want
return [button1]
}
I tried it with and without your tableView method and it seemed to work fine both ways but I don't think your method is necessary if you choose this route
Hope this helps

how to perform specific action at certain table view row in swift?

I have a table view cell. I make an app for a tenant in the apartment to report the defect of the room facility. if the defect has been repaired (status: Complete), data from server will give defect.status == 2 (if defect.status == 1, still on process to be repaired), and it will show YES and NO Button like the picture above.
I want if it still on the repairment process, the view that contains "Are You satisfied" label and Yes No Button will not appear. The expected result should be like the picture below
here is the code I use to remove that satisfied or not view
extension RequestDefectVC : UITableViewDataSource {
//MARK: Table View Delegate & Datasource
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return listDefects.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.removeFromSuperview()
}
}
return cell
}
}
but unfortunately, if that wantToRemoveView.removeFromSuperview() is triggered, it will remove all the view in all cell, even though the status is completed like picture below
I want that satisfied or not view appears if the status is complete, otherwise, it will be removed. how to do that ?
For your costumed cells are reused, removing views will cause uncertain effects. You don't actually need the specific view to be removed, only if it stays invisible.
if dataDefect.status == 2 {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.isHidden = true
}
} else {
if let wantToRemoveView = cell.commentResponseView {
wantToRemoveView.isHidden = false
}
}
Create a height constraint for that view and hook it as IBOutlet and control it's constant according to that in cellForRowAt
self.askViewH.constant = show ? 50 : 0
cell.layoutIfNeeded()
return cell
I expect you using automatic tableView cells
#Alexa289 One suggestion is that you can take heightConstraints of UIView. then create IBOutlet of your height constraints and make its constant 0 when you want to hide otherwise assign value to your static height.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
cell.viewSatisficationHeightConstraints.constant = 50
} else {
cell.viewSatisficationHeightConstraints.constant = 0
}
return cell
}
Second suggestion is that you can take label and button in view and embed stackview to your view(view contain label and button)
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "defectCell", for: indexPath) as! RequestDefectCell
let dataDefect = listDefects[indexPath.row]
cell.defectData = dataDefect
if dataDefect.status == 2 {
cell.viewSatisfication.isHidden = false
} else {
cell.viewSatisfication.isHidden = true
}
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return UITableViewAutomaticDimension
}
override func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {
return 40
}
you can read about UIStackView which makes hiding things easier. If you are not using stackview and hiding things the UI will not good as the space used by the hidden view will be still there. So better to use stackView when need to hide or show some view.
UIStackView : https://developer.apple.com/documentation/uikit/uistackview

Why in heightForRowAt method my cell is nil?

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if let cell = tableView.cellForRow(at: indexPath) as? ExpandablePlaneTableViewCell {
return 400.0
}
return 75.0
}
I want to change size of my cell but inside of heightForRowAt it cannot see my cell and crashed. When I put there if let check it does not enter inside of the block and just takes 75.
Can anyone tell me what the problem is? It's too strange for me!
I already set delegate to self. So it call the function but cannot detect my cell there.
UPDATE
In my ExpandablePlaneTableViewCell I have a variable:
var exapanded = false
Later in my ViewController: On click on the button in the cell I run my delegate method:
func expandViewButtonTapped(_ sender: ExpandablePlaneTableViewCell, for indexPath: IndexPath) {
sender.exapanded = true
tableView.reloadRows(at: [indexPath], with: .automatic)
}
and after I want to expand it and reload the cell
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "expandableCell", for: indexPath) as! ExpandablePlaneTableViewCell
cell.delegate = self
cell.indexPath = indexPath
return cell
}
Do not attempt to get a cell in heightForRowAt. And there certainly is no reason to do so in your case.
You seem to want the height to be one value for certain types of cells and another height for other types.
Simply use the same basic logic you have in cellForRowAt, based on the indexPath, to determine which height to return. In other words, base the decision on your data model, not on the cell.

Disable selection of a cell without UserInteractionEnabled in Swift

I have a cell with a button and setting UserInteractionEnabled to false disables the button too. Now if I use cell.selectionStyle = UITableViewCellSelectionStyle.None. Although the cell doesn't get highlighted but I loose the previous selected cell. Any way to overcome this?
Implement the UITableView delegate method
tableView(_ tableView: UITableView, willSelectRowAtIndexPath indexPath: NSIndexPath) -> NSIndexPath?
Return nil for the row you don't want to be able to be selected.
... and for Swift 3, the delegate method is:
public func tableView(_ tableView: UITableView, willSelectRowAt indexPath: IndexPath) -> IndexPath? {
if indexPath.row == 0 {
return nil
} else {
return indexPath
}
}

Resources