Populating Cells in a tableView from API Call - ios

Question

I am forced to use an asynchronous call (I guess closure in swift) to get Data I need using an SDK (APIWrapper). I'm finding that the view is being initalized before I am able to get the data that I need.
So my 1st question to y'all is, how can I get my cells to bring in the data that I need to the table view before the view loads? Then, why would I want to use an asyncronous call at this point
import APIWrapper
import UIKit
class MyViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
let provider = APIWrapper
var categories = [String]()
//define number of cells
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
categories = []
self.getCells()
print("count " , self.categories.count)
return(self.categories.count)
}
//get number of cells
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "categories")
cell.textLabel?.text = categories[indexPath.row]
return(cell)
}
private func getCells(){
provider?.getCategoriesWithCallback { (response, error) -> () in
if error == nil {
print("response ", response)
self.updateTableViewWithCategories(categories: response as! [APIWrapperCategory])
}
else {
print("FUCKK")
}
}
}
private func updateTableViewWithCategories(categories: [APIWrapperCategory]){
for category in categories{
print("category obj " , category)
print("category name " , category.name)
}
}
}
The output from my console looks like
count 0
count 0
count 0
count 0
response Optional([<APIWrapperCategory: 0x6000002a0300>])
category obj <ZDKHelpCenterCategory: 0x6000002a0300>
category name General
response Optional([<ZDKHelpCenterCategory: 0x6180002a30c0>])
category obj <ZDKHelpCenterCategory: 0x6180002a30c0>
category name General
response Optional([<ZDKHelpCenterCategory: 0x6180002a30c0>])
category obj <ZDKHelpCenterCategory: 0x6180002a30c0>
category name General
response Optional([<ZDKHelpCenterCategory: 0x6180002a3300>])
category obj <ZDKHelpCenterCategory: 0x6180002a3300>
category name General

Answer 1

You are getting data for your table view from the data source method of the tableview.
To get data from an API call, call self.getCells() method in viewDidLoad() method of your view controller like this:
override func viewDidLoad() {
//your code here
//get cells data
self.getCells()
}
And add your api response data to table view data source as:
private func updateTableViewWithCategories(categories: [APIWrapperCategory]){
self. categories = []
for category in categories{
print("category obj " , category)
print("category name " , category.name)
self. categories.append(category.name)
}
//reload table view here
DispatchQueue.main.async {
self.yourTableView.reloadData()
}
}
and change the delegate method as:
//define number of cells
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("count " , self.categories.count)
return(self.categories.count)
}

Answer 2

So I ended up using viewWillAppear and changed a few things on the way data is returned to make the cells populate so here's the code, I hope this can help someone else out
#IBOutlet weak var tableView: UITableView!
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
self.getCategoriesFromZendesk()
}
//define number of cells
public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("count " , self.categories.count)
return self.categories.count
}
//get number of cells
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//Add Label to the Prototype Cell
let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "categories")
cell.textLabel?.text = categories[indexPath.row]
return(cell)
}
private func getCategories(){
self.categories = []
provider?.getCategoriesWithCallback { (response, error) -> () in
if error == nil {
print("response ", response?.map{($0 as AnyObject as? APIWrapperCategory)?.name ?? ""} ?? "empty")
self.updateTableViewWithCategories(categories: response as? [APIWrapperCategory])
}
else {
print("FUCKK")
}
}
}
private func updateTableViewWithCategories(categories: [APIWrapperCategory]?){
self.categories = categories?.flatMap{$0.name} ?? []
tableView.reloadData()
}