Multiple Selection of UITableView Cells with Scrolling [duplicate] - ios

Question

I have to make checkmarks on a tableView, but if I'm scrolling and one check marked cell is not visible and I scroll back the checkmark disappeared.
While running this code
var boolArray = [Bool]()
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
var cell:UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
if cell.accessoryType == UITableViewCellAccessoryType.Checkmark {
cell.accessoryType = UITableViewCellAccessoryType.None
boolArray[indexPath.row] = false
}
else
{
cell.accessoryType = UITableViewCellAccessoryType.Checkmark
boolArray[indexPath.row] = true
}
println(boolArray)
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
boolArray.append(false)
var view = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "CellTable")
return view
}
After a little bit scrolling and checkmarking, the printed array is this big...
[true, false, true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false]

Answer 1

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
var cell : UITableViewCell = .........
if(boolArray[indexPath.row){
cell.accessoryType = UITableViewCellAccessoryType.Checkmark
} else {
cell.accessoryType = UITableViewCellAccessoryType.None
}
}
Try this code.

Answer 2

Create an Array of tuples to store row and section values:
var selectedCells:[(row: Int, section: Int)] = []
In your cellForRowAtIndexPath, check if you have any selectedCellValues. If so, add an accessoryType for that cell and break out of the loop,
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{
let cell = tableView.dequeueReusableCellWithIdentifier("SettingsCell", forIndexPath: indexPath) as SettingsCustomCell
var rowNums:NSNumber = indexPath.row
var sectionNums:NSNumber = indexPath.section
var selectedRow:Int
var selectedSection:Int
if(selectedCells.count > 0){
for tuple in selectedCells{
selectedRow = tuple.row
selectedSection = tuple.section
if(selectedRow == rowNums && selectedSection == sectionNums){
cell.accessoryType = UITableViewCellAccessoryType.Checkmark
break
}else{
cell.accessoryType = UITableViewCellAccessoryType.None
}
}
}else{
cell.accessoryType = UITableViewCellAccessoryType.None
}
var keyValue = listOfSectionTitles[indexPath.section]
var items: [NSString] = dictionaryOfCellTitles.objectForKey(keyValue) as [NSString]
cell.textLabel?.text = items[indexPath.row]
return cell
}
Handle selectedcellvalues in didSelecteRowAtIndexPath:
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
let cell = tableView.cellForRowAtIndexPath(indexPath)
if(cell?.accessoryType == UITableViewCellAccessoryType.None){
cell?.accessoryType = UITableViewCellAccessoryType.Checkmark
selectedCells.append(row:indexPath.row, section:indexPath.section)
}else{
var rowToDelete = indexPath.row
var sectionToDelete = indexPath.section
for var i=0; i < selectedCells.count; i++
{
if(rowToDelete == selectedCells[i].row && sectionToDelete == selectedCells[i].section){
selectedCells.removeAtIndex(i)
cell?.accessoryType = UITableViewCellAccessoryType.None
}
}
}
tableView.deselectRowAtIndexPath(indexPath, animated: true)
}

Answer 3

An NSMutableIndexSet is a better object to use to track selection status.
You also need to check the selection status when you return the cell for an indexPath
var selectedCells = NSMutableIndexSet()
func tableView(_ tableView: UITableView, didSelectRowAtIndexPath indexPath: IndexPath) {
var accessory=UITableViewCellAccessoryType.none
if (selectedCells.containsIndex(indexPath.row) {
selectedCells.removeIndex(indexPath.row)
}
else {
selectedCells.addIndex(indexPath.row)
accessory=.checkmark
}
if let cell = tableView.cellForRowAtIndexPath(indexPath) {
cell.accessoryType = accessory
}
}
func tableView(_ tableView: UITableView, cellForRowAtIndexPath indexPath: IndexPath) -> UITableViewCell
{
var cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier:"CellTable")
var accessory=UITableViewCellAccessoryType.none
if (selectedCells.containsIndex(indexPath.row) {
accessory = .checkmark
}
view.accessoryType=accessory
return view
}

Answer 4

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
reuses cells as you can see from the code. You need to keep the state of your selected cells, and assign the accessory views state after var view = UITableViewCell ...

Answer 5

Your error is in cellForRowAtIndexPath when you do boolArray.append(false). cellForrRowAtIndexPath: is called every time a cell will be drawn even if it has been drawn before. A possible fix is only appending false if indexPath.row is greater than the length of boolArray, otherwise it is your 'model' and you just check it.