Display different tableview data depending on which collectionview cell is selected - swift

Question

Here's a screenshot of the UI
I have a collectionview above my tableview. I'm trying to get the tableview's data to change based on which collectionview cell is selected.
This view handles menu item selection, and menu items are displayed in the tableview. The categories for these menu items are displayed in a horizontally-scrolling collectionview right above the tableview.
The restaurant class has an instance variable .categories which returns an array of strings. This is what populates the collectionview. The menu item class has an instance variable .category which returns a single string. I intend to match these two.
My intended result: For each selected cell in the collectionview, take its category name and communicate it to the tableview. The tableview should take this name and filter through its menu items to check for matching category names. Display those specific tableview cells.
For my collectionview:
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
if let count = restaurant?.categories.count {
return count
} else {
return 0
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath) as! CategoryCell
// Sets label text and images for each category
cell.categoryLabel.text = restaurant?.categories[indexPath.row]
if UIImage(named: (restaurant?.categories[indexPath.row])!) != nil {
cell.buttonView.image = UIImage(named: (restaurant?.categories[indexPath.row])!)
}
return cell
}
For my tableview:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let count = restaurant?.menuItems.count {
return count
} else {
return 0
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = masterTableView.dequeueReusableCell(withIdentifier: "menuCell", for: indexPath) as! MenuItemCell
cell.selectionStyle = UITableViewCell.SelectionStyle.none
let currentItem = restaurant?.menuItems[indexPath.row]
cell.item = currentItem
return cell
}
Right now, my result (obviously) is that simply all of my menu items are being displayed in the tableview, regardless of which collectionview cell is selected.

Answer 1

Two things needed in following format for your question.
1. restaurant?.categories values:
[popular, milk tea, snacks, tea, ...]
2. restaurant?.menuItems values:
{
popular : [
{
"name" : "thai-tea",
"price": "$6",
"thumbnailURL" : "https://.../thai.png"
},
{
"name" : "milk-tea",
"price": "$3",
"thumbnailURL" : "https://.../ml.png"
}
],
snacks : [
{
"name" : "brownie",
"price": "$7",
"thumbnailURL" : "https://.../brw.png"
},
{
"name" : "pasta",
"price": "$3",
"thumbnailURL" : "https://.../pas.png"
}
]
}
Global Variable
var whichCellSelect : Int = 0
CollectionView
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
whichCellSelect = indexPath.item
yourTableView.reloadData()
}
Tableview
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
if let count = restaurant?.menuItems.count {
return count
} else {
return 0
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = masterTableView.dequeueReusableCell(withIdentifier: "menuCell", for: indexPath) as! MenuItemCell
cell.selectionStyle = UITableViewCell.SelectionStyle.none
let currentCategory = restaurant?.categories[whichCellSelect] // You will get String here
let currentMenuItem = restaurant?.menuItems[currentCategory] // You will get Array here
cell.item = currentItem
return cell
}
Notes
Make sure, restaurant?.categories data type as [String] and restaurant?.menuItems data type as [String : Any] . This is one of the simplest way to understand data transfer within UIViewController

Answer 2

How are the different categories stored? Are you using an array for each category and sending that specific array to the TableView after an option in the CollectionView is selected? Then you would need to refresh the TableView so the changes are reflected in the interface.
I alsso can't see where you're getting what the user pressed in the CollectionView. ... can you not use something like this ...
func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
}
to get what they've selected, use that choice to update the table by writing a different array or only adding certain array elements depending on the category then use reloadData() to refresh the table.