collectionView didSelectItemAt superview not selecting the correct Object - ios

Question

I have a list of sensors in a collectionView inside a UIView class called MyCropView where I show some data about that crop.
Im trying to change the value of some sensors like the icon and the background color on each click.
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
let myCropCard = collectionView.superview as! MyCropCard
let sensor = myCropCard.sensors[indexPath.row]
let cell = myCropCard.superview
//Change the color and icon of the sensors
if let cell = collectionView.cellForItem(at: indexPath) as? MyCollectionViewCell {
//Previous cell in grey
if !self.lastSelectedIndexPath.isEmpty {
let lastCell = collectionView.cellForItem(at: self.lastSelectedIndexPath) as? MyCollectionViewCell
lastCell?.imageView.backgroundColor = UIColor(red: 0.95, green: 0.95, blue: 0.95, alpha: 1.0)
lastCell?.imageView.image = UIImage(named: self.lastSelectedImageName )
}
//Makes sensor green onSelect
cell.imageView.backgroundColor = UIColor(red: 0.882, green: 0.95, blue: 0.882, alpha: 1.0)
cell.imageView.image = UIImage(named: sensor.getType() )
self.lastSelectedIndexPath = indexPath
self.lastSelectedImageName = String(format: "%#_deactivated", sensor.getType())
}
//Show all the alerts of each sensor
for alert:Alert in sensor.getAlerts() {
let viewSensor = cell?.viewWithTag(300) as! SensorView
viewSensor.lblSensor.text = sensor.getTipo()
viewSensor.lblBotLog.text = alerta.getNombreDispositivo()
viewSensor.lblMin.text = String(format: "MIN %.0f", alert.getMin())
viewSensor.lblMax.text = String(format: "MAX %.0f", alert.getMax())
viewSensor.btnDel.tag = Int(alert.getId() + 1000)
viewSensor.btnDel.addTarget(
self,
action: #selector( viewSensor.deleteAlert(_:) ),
for: .touchUpInside
)
viewSensor.isHidden = false
}
}
That collectionView is the list of sensors we have. It works fine with 1st MyCropCard, But doesn't for multiple MyCropCards. Superview takes the first cropCard of them all, not the collectionView's parent.
I would like to know how can I correctly have the parent of the selected collectionView?

Answer 1

Your code is cluttered with unneccessary logic-related codes, which are probably unrelated to the issue.
Also, extensive use of tags are making the code unscalable and hard to maintain, so it probably needs a heavy refactoring.
The following code is basically a MWE for what you want to achieve (If I misunderstood your issue, let me know).
To explain the code, this is a custom tableViewCell:
class TableViewCell: UITableViewCell {
var collectionView: UICollectionView? {
didSet {
guard let collectionView = collectionView else { return }
contentView.addSubview(collectionView)
collectionView.translatesAutoresizingMaskIntoConstraints = false
collectionView.backgroundColor = .white
setupCollectionViewLayout(collectionView)
}
}
private func setupCollectionViewLayout(_ collectionView: UICollectionView) {
NSLayoutConstraint.activate([
collectionView.leadingAnchor
.constraint(equalTo: contentView.leadingAnchor),
collectionView.trailingAnchor
.constraint(equalTo: contentView.trailingAnchor),
collectionView.topAnchor
.constraint(equalTo: contentView.topAnchor),
collectionView.bottomAnchor
.constraint(equalTo: contentView.bottomAnchor),
])
}
}
setupCollectionViewLayout simply enables AutoLayout. collectionView will be later added when a tableViewCell instance is dequeued.
class CollectionViewCell: UICollectionViewCell {}
class ViewController: UIViewController {
private var lastSelectedCollectionViewCell: CollectionViewCell?
private lazy var tableView: UITableView = {
let tableView = UITableView()
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.delegate = self
tableView.dataSource = self
tableView.register(TableViewCell.self, forCellReuseIdentifier: "cell")
return tableView
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(tableView)
setupTableViewLayout(tableView)
}
private func setupTableViewLayout(_ tableView: UITableView) {
NSLayoutConstraint.activate([
tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
tableView.topAnchor.constraint(equalTo: view.topAnchor),
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
])
}
}
tableView is added as the view is loaded, and AutoLayout constraints are added by setupTableViewLayout.
Note that you keep a copy of the last index path, but I think it is better and simpler to keep a reference to the cell itself.
In UITableViewDataSource extension:
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(
withIdentifier: "cell",
for: indexPath) as! TableViewCell
guard cell.collectionView == nil else { return cell }
let collectionView = UICollectionView(
frame: .zero,
collectionViewLayout: UICollectionViewFlowLayout())
collectionView.dataSource = self
collectionView.delegate = self
collectionView.register(CollectionViewCell.self, forCellWithReuseIdentifier: "cell")
cell.collectionView = collectionView
return cell
}
}
extension ViewController: UITableViewDelegate {}
I add a collectionView only if it doesn't already exist in a tableViewCell.
collectionView assigns dataSource and delegate as self, though it would be better if there is an extra modelController object.
UITableViewDelegate is empty.
Now extensions for the collectionViews:
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
cell.backgroundColor = .gray
return cell
}
}
extension ViewController: UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
lastSelectedCollectionViewCell?.backgroundColor = .gray
if let cell = collectionView.cellForItem(at: indexPath) as? CollectionViewCell {
cell.backgroundColor = .yellow
lastSelectedCollectionViewCell = cell
}
}
}
extension ViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 20, height: 20)
}
}
The important part is collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath), and the others are just boilerplate code.
When a collectionViewCell is selected, the self.lastSelectedCollectionViewCell's color turns back to gray, and the newly selected cell is assigned to lastSelectedCollectionViewCell, after its backgroundColor changed.
The following is the entire code you can run in Playground:
import UIKit
import PlaygroundSupport
class TableViewCell: UITableViewCell {
var collectionView: UICollectionView? {
didSet {
guard let collectionView = collectionView else { return }
contentView.addSubview(collectionView)
collectionView.translatesAutoresizingMaskIntoConstraints = false
collectionView.backgroundColor = .white
setupCollectionViewLayout(collectionView)
}
}
private func setupCollectionViewLayout(_ collectionView: UICollectionView) {
NSLayoutConstraint.activate([
collectionView.leadingAnchor
.constraint(equalTo: contentView.leadingAnchor),
collectionView.trailingAnchor
.constraint(equalTo: contentView.trailingAnchor),
collectionView.topAnchor
.constraint(equalTo: contentView.topAnchor),
collectionView.bottomAnchor
.constraint(equalTo: contentView.bottomAnchor),
])
}
}
class CollectionViewCell: UICollectionViewCell {}
class ViewController: UIViewController {
private var lastSelectedCollectionViewCell: CollectionViewCell?
private lazy var tableView: UITableView = {
let tableView = UITableView()
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.delegate = self
tableView.dataSource = self
tableView.register(TableViewCell.self, forCellReuseIdentifier: "cell")
return tableView
}()
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
view.addSubview(tableView)
setupTableViewLayout(tableView)
}
private func setupTableViewLayout(_ tableView: UITableView) {
NSLayoutConstraint.activate([
tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
tableView.topAnchor.constraint(equalTo: view.topAnchor),
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
])
}
}
extension ViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(
withIdentifier: "cell",
for: indexPath) as! TableViewCell
guard cell.collectionView == nil else { return cell }
let collectionView = UICollectionView(
frame: .zero,
collectionViewLayout: UICollectionViewFlowLayout())
collectionView.dataSource = self
collectionView.delegate = self
collectionView.register(CollectionViewCell.self, forCellWithReuseIdentifier: "cell")
cell.collectionView = collectionView
return cell
}
}
extension ViewController: UITableViewDelegate {}
extension ViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 10
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
cell.backgroundColor = .gray
return cell
}
}
extension ViewController: UICollectionViewDelegate {
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
lastSelectedCollectionViewCell?.backgroundColor = .gray
if let cell = collectionView.cellForItem(at: indexPath) as? CollectionViewCell {
cell.backgroundColor = .yellow
lastSelectedCollectionViewCell = cell
}
}
}
extension ViewController: UICollectionViewDelegateFlowLayout {
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
return CGSize(width: 20, height: 20)
}
}
PlaygroundPage.current.liveView = ViewController()