how to use indexpath.row outside the table function - ios

Question

my tableview is
struct country : Decodable {
let name : String
let capital : String
let region : String
}
class ViewController: UIViewController {
var countries = [country]()
let color = UIColor()
#IBOutlet weak var tableview: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableview.delegate = self
tableview.dataSource = self
let jsonurl = "https://restcountries.eu/rest/v2/all"
let url = URL(string: jsonurl)
URLSession.shared.dataTask(with: url!) { (data, response, error) in
do {
self.countries = try JSONDecoder().decode([country].self, from: data!)
} catch {
print("Error")
}
DispatchQueue.main.async {
self.tableview.reloadData()
}
}.resume()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func redButtonAction(_ sender: UIButton) {
let index = IndexPath.init(row: 0, section: 0)
let cell = tableview.cellForRow(at: index)
}
}
extension ViewController:UITableViewDelegate,UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection
section: Int) -> Int {
return countries.count
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath:
IndexPath) -> CGFloat {
return 40
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableview.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = countries[indexPath.row].name.capitalized
let cellnumber = indexPath.row
return cell
}
now I want to use cellnumber or indexpath.row in my button action. I do this but i can not get indexpath.row
I want to do when I pressed the button at that time the odd number cell of the tableview 's background color change in red and even number cell 's background color change blue. But problem is out side tableview function I get only one value not whole number of array. In above program if I print cellnumber we get whole number of cell.

Answer 1

table view cell is reusable and you can get only visible cell's indexPath so you should reload table view on clicked of button and need to put condition if you want to change color or not in cellForRowAt
Code for change row color on button clicked
struct country : Decodable {
let name : String
let capital : String
let region : String
}
class ViewController : UIViewController {
var countries = [country]()
let color = UIColor()
var needToChangeColor : Bool = false
#IBOutlet weak var tableview: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableview.delegate = self
tableview.dataSource = self
let jsonurl = "https://restcountries.eu/rest/v2/all"
let url = URL(string: jsonurl)
URLSession.shared.dataTask(with: url!) { (data, response, error) in
do {
self.countries = try JSONDecoder().decode([country].self, from: data!)
} catch {
print("Error")
}
DispatchQueue.main.async {
self.tableview.reloadData()
}
}.resume()
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
#IBAction func redButtonAction(_ sender: UIButton) {
self.needToChangeColor = true
self.tableview.reloadData()
}
}
extension ViewController :UITableViewDelegate,UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection
section: Int) -> Int {
return countries.count
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath:
IndexPath) -> CGFloat {
return 40
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableview.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = countries[indexPath.row].name.capitalized
if needToChangeColor == true {
if indexPath.row % 2 == 0 {
cell.backgroundColor = UIColor.blue
} else {
cell.backgroundColor = UIColor.red
}
} else {
cell.backgroundColor = UIColor.white
}
return cell
}
}

Answer 2

The very basic solution would be adding a tag for your button in cellForRowAt. It will work in case you have only one section.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableview.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
cell.textLabel?.text = countries[indexPath.row].name.capitalized
cell.button.tag = indexPath.row
return cell
}
Now in your method
#IBAction func redButtonAction(_ sender: UIButton) {
let index = IndexPath.init(row: sender.tag, section: 0)
let cell = tableview.cellForRow(at: index)
}
Unfortunately this approach will not be so efficient if you add any complexity to your tableView layout.