Converting 3 seperate arrays of dictionaries into 1 struct array? - ios

Question

I am currently using 3 separate arrays to populate a sectioned UITableView and I'd like to use just a single array for filtering purposes but still maintain the sections within my table.
The data is fed by a single JSON string which I then iterate through to create a dictionary of a single 'Event' and then based on the value of 'Event Status', it is added to one of three arrays (open, closed and deferred). These arrays are then uses to populate each section of a UITableView.
let myDictionary: [String: String] = [
"EventID" : item["EventID"] as! String,
"EventTitle" : item["EventTitle"] as! String,
"EventSummary" : item["EventSummary"] as! String,
"EventStatus" : item["Status"] as! String
]
if (item["Status"] as! String == "Open") {
self.openEvents.append(myDictionary as AnyObject)
}
if (item["Status"] as! String == "Closed") {
self.closedEvents.append(myDictionary as AnyObject)
}
if (item["Status"] as! String == "") {
self.deferredEvents.append(myDictionary as AnyObject)
}
Then in cellForRowAt:
var tmpDict: [String: String] = ["":""]
if sectionHeaders[indexPath.section] == "Open" {
tmpDict = openEvents[indexPath.row] as! [String : String]
}
if sectionHeaders[indexPath.section] == "Closed" {
tmpDict = closedEvents[indexPath.row] as! [String : String]
}
if sectionHeaders[indexPath.section] == "Deferred" {
tmpDict = deferredEvents[indexPath.row] as! [String : String]
}
Problem is that in order to allow filtering of this data, I'd have to run the filter against three different arrays which means three different 'filtered data' arrays. Which is far from ideal.
What I'd like to achieve is to have a single array of structured data (as opposed to dictionaries) that the user can filter through and the result returned to a single 'filtered data' array. I am doing this elsewhere with good effect, however, that is for a single list, not sectioned.
I have a struct setup and adding items to it as follows:
let data = EventItem(EventID: item["EventID"] as! String, EventTitle: item["EventTitle"] as! String, EventSummary: item["EventSummary"] as! String, EventStatus: item["Status"] as! String)
self.eventList.append(data)
and filtering using:
filteredData = eventList.filter() {
($0.EventTitle.lowercased() as NSString).contains(searchText.lowercased()) || ($0.EventSummary.lowercased() as NSString).contains(searchText.lowercased())
}
eventsTable.reloadData()
Is it possible to split this single array over different sections in a TableView? if so, how?

Answer 1

I would suggest giving a little more responsibility to your EventItem struct to help with the data source response. The you can then use a two dimensional array to manage both the section and row contents.
For example:
struct EventItem
{
var EventID = ""
var EventTitle = ""
var EventSummary = ""
var EventStatus = ""
func matches(_ searchText:String) -> Bool
{
return EventTitle.lowercased().contains(searchText.lowercased())
|| EventSummary.lowercased().contains(searchText.lowercased())
}
var section:Int
{
return EventStatus == "Opened" ? 0
: EventStatus == "Closed" ? 1
: 2
}
}
// you can maintain an "master" array of events (or build them from the dictionary as needed)
// I' using an array to keep the example simple
var eventList:[EventItem] = []
// This 2D array in your controller will serve as the store for your table view data source
var sectionData:[[EventItem]] = []
// applying filter is one line once you've added utility functions to your struct
sectionData = Array(0..<3).map{ section in return eventList.filter{$0.section == section && $0.matches(searchText)} }
// responding to tableview data source protocol only requires one line
// (which will not change even if you break down your data into more sections)
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{ return sectionData[section].count }
// getting to the data to populate the table view cell will be quite straightforward
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let rowData = sectionData[indexPath.section][indexPath.row]
// setup cell ...
}

Answer 2

You can just use an extension of the approach you already have for filteredData
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
switch section {
case 0:
let sortedList = newItems.sorted { $0.eventStatus == "Open"}
return sortedList.count
case 1:
let sortedList = newItems.sorted { $0.eventStatus == "Closed"}
return sortedList.count
case 2:
let sortedList = newItems.sorted { $0.eventStatus == ""}
return sortedList.count
default:
return 0 // shouldn't happen
}
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
var tmpDict: [String: String] = ["":""]
switch section {
case 0:
tmpDict = newItems.sorted { $0.eventStatus == "Open"}
case 1:
tmpDict = newItems.sorted { $0.eventStatus == "Closed"}
case 2:
tmpDict = newItems.sorted { $0.eventStatus == ""}
default:
return 0 // shouldn't happen
// setup cell
}