Stored selected indexPath of UICollectionView inside UITableView - ios

Question

I'm currently making a screen that has an UITableView with many sections that have the content of cells is UICollectionView. Now I'm saving the selected indexPath of the collection into an array then save to UserDefaults (because the requirement is showing all cells has selected before when reopening view controller).
But I have the issues is when I reopen view controller all items in all sections with the same selected indexPath show the same state.
I know it occurs because I just save the only indexPath of the selected item without the section of UITableview which is holding the collection view. But I don't know how to check the sections. Can someone please help me to solve this problem? Thank in advance.
I'm following this solution How do I got Multiple Selections in UICollection View using Swift 4
And here is what I do in my code:
var usrDefault = UserDefaults.standard
var encodedData: Data?
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
if let act = usrDefault.data(forKey: "selected") {
let outData = NSKeyedUnarchiver.unarchiveObject(with: act)
arrSelectedIndex = outData as! [IndexPath]
}else {
arrSelectedData = []
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let optionItemCell = collectionView.dequeueReusableCell(withReuseIdentifier: "optionCell", for: indexPath) as! SDFilterCollectionCell
let title = itemFilter[indexPath.section].value[indexPath.item].option_name
if arrSelectedIndex.contains(indexPath) {
optionItemCell.filterSelectionComponent?.bind(title: title!, style: .select)
optionItemCell.backgroundColor = UIColor(hexaString: SDDSColor.color_red_50.rawValue)
optionItemCell.layer.borderColor = UIColor(hexaString: SDDSColor.color_red_300.rawValue).cgColor
}else {
optionItemCell.backgroundColor = UIColor(hexaString: SDDSColor.color_white.rawValue)
optionItemCell.layer.borderColor = UIColor(hexaString: SDDSColor.color_grey_100.rawValue).cgColor
optionItemCell.filterSelectionComponent?.bind(title: title!, style: .unselect)
}
optionItemCell.layoutSubviews()
return optionItemCell
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let strData = itemFilter[indexPath.section].value[indexPath.item]
let cell = collectionView.cellForItem(at: indexPath) as? SDFilterCollectionCell
cell?.filterSelectionComponent?.bind(title: strData.option_name!, style: .select)
cell?.backgroundColor = UIColor(hexaString: SDDSColor.color_red_50.rawValue)
cell?.layer.borderColor = UIColor(hexaString: SDDSColor.color_red_300.rawValue).cgColor
if arrSelectedIndex.contains(indexPath) {
arrSelectedIndex = arrSelectedIndex.filter{($0 != indexPath)}
arrSelectedData = arrSelectedData.filter{($0 != strData)}
}else {
arrSelectedIndex.append(indexPath)
arrSelectedData.append(strData)
encodedData = NSKeyedArchiver.archivedData(withRootObject: arrSelectedIndex)
usrDefault.set(encodedData, forKey: "selected")
}
if let delegate = delegate {
if itemFilter[indexPath.section].search_key.count > 0 {
if (strData.option_id != "") {
input.add(strData.option_id!)
let output = input.componentsJoined(by: ",")
data["search_key"] = itemFilter[indexPath.section].search_key.count > 0 ? itemFilter[indexPath.section].search_key : strData.search_key;
data["option_id"] = output
}
}else {
data["search_key"] = itemFilter[indexPath.section].search_key.count > 0 ? itemFilter[indexPath.section].search_key : strData.search_key;
data["option_id"] = strData.option_id
}
delegate.filterTableCellDidSelectItem(item: data, indexPath: indexPath)
}
}

Answer 1

This will only work based on the assumption that both your parent table view and child collection views both are not using multiple sections with multiple rows and you only need to store one value for each to represent where an item is located in each respective view.
If I am understanding correctly, you have a collection view for each table view cell. You are storing the selection of each collection view, but you need to also know the position of the collection view in the parent table? A way to do this would be to add a property to your UICollectionView class or use the tag property and set it corresponding section it is positioned in the parent table. Then when you save the selected IndexPath, you can set the section to be that collection view's property you created(or tag in the example) so that each selected indexPath.section represents the table view section, and the indexPath.row represents the collection view's row.
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//...
let collectionView = UICollectionView()
collectionView.tag = indexPath.section
//...
}
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
indexPath.section = collectionView.tag
let strData = itemFilter[indexPath.section].value[indexPath.item]
//...
}
Basically each selected index path you save will correspond to the following:
indexPath.section = table view section
indexPath.row = collection view row
IndexPath(row: 5, section: 9) would correlate to:
--table view cell at IndexPath(row: 0, section: 9) .
----collection view cell at IndexPath(row: 5, section: 0)
Edit: This is how you can use the saved index paths in your current code
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
//...
let tempIndexPath = IndexPath(row: indexPath.row, section: collectionView.tag)
if arrSelectedIndex.contains(tempIndexPath) {
//...
} else {
//...
}
//...
}

Answer 2

Your statement arrSelectedIndex.contains(indexPath) in the cellForItemAt method is not correct.
Each time a UICollectionView in a UITableView's section is loaded, this will called the cellForItemAt for ALL cells.
Here is the error :
In your GIF example the first cell is selected in the first collectionView, you will store (0, 0) in the array.
But when the second collectionView will loads its cells, it will check if the indexPath (0, 0) is contained into your array. It is the case, so the backgroundColor will be selected.
This error will be reproduced on every collectionView stored in your tableView sections.
You should probably also store the sectionIndex of your UITableView into your array of IndexPath.