Swift - Handling custom checkmark button state on multiple sections of tableview - ios

Question

I have a tableview with multiple sections each section is having 3 cells , each cell contains the custom check mark button. Where user can change check and uncheck images of check button on click.
The problem is, i am changing the cell button image from uncheck to check when user click on button which is working fine. If i scroll the tableview that check mark image is adding to wrong cell.
I googled it and found the solution like saving clicked cell indexPath.row in array and removing from array if user click again on same cell.
It is not working as i have multiple sections.
Please provide me any suggestion to find out the solution for my problem.
// Button action.
func buttonTappedOnCell(cell: customeCell) {
let indexPath : IndexPath = self.tableView.indexPath(for: cell)!
if self.selectedIndexPath.count > 0 {
for selectedIndex in self.selectedIndexPath {
if selectedIndex as! IndexPath == indexPath {
self.selectedIndexPath.remove(indexPath)
} else {
self.selectedIndexPath.add(indexPath)
}
}
} else {
self.selectedIndexPath.add(indexPath)
}
Code in cellForRowAtIndexPath
for anIndex in self.selectedIndexPath {
if anIndex as! IndexPath == indexPath {
cell.checkMarkButton.setBackgroundImage(UIImage(named: "checkMark"), for: .normal)
} else {
cell.checkMarkButton.setBackgroundImage(UIImage(named: "UnCheckMark"), for: .normal)
}
}

Answer 1

You can simplify your code greatly by using a Set<IndexPath>. There is no need to loop through an array.
var selectedPaths=Set<IndexPath>()
func buttonTappedOnCell(cell: customeCell) {
if let indexPath = self.tableView.indexPath(for: cell) {
var image = UIImage(named: "CheckMark")
if self.selectedPaths.contains(indexPath) {
image = UIImage(named: "UnCheckMark")
self.selectedPaths.remove(indexPath)
} else {
self.selectedPaths.insert(indexPath)
}
cell.checkMarkButton.setBackgroundImage(image, for: .normal)
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "identifier", for: indexPath) as! YourCellType
...
var image = UIImage(named: "UnCheckMark")
if self.selectedPaths.contains(indexPath) {
image = UIImage(named: "checkMark")
}
cell.checkMarkButton.setBackgroundImage(image, for: .normal)
return cell
}

Answer 2

This happens because the cells of a tableView are reused to minimise memory usage.
If you are using a custom implementation of check button then you have to store the values for the cell which is selected in a data Structure like an array for example if you have 2 sections with 3 elements in each section with 2nd item in 1st section selected, then the data structure like an array can be like [[false, true, false], [false, false. false]].
Here I am setting true in case the cell is selected. Update the values of this data structure and check from it when applying the image in the cellForRowAt and apply the checkedImage only when the indexPath.section and indexPath.row for Array return a true Bool.
Hope this helps. Feel free to reach out in case of any doubts. Happy coding.

Answer 3

inside of your TableView DidSelect method just put
let cell = tableView.cellForRowAtIndex(indexPath).accessoryType = UITableViewCell.accessoryType = Checkmark
vice versa for DidDeselect method but change the Checkmark into None.
let cell = tableView.cellForRowAtIndex(indexPath).accessoryType = UITableViewCell.accessoryType = None
If you create more complex code for a simple method, It'll give you disaster.