iOS multiple JSON file data transfer through segue in Swift - ios

Question

I am trying to make a country weather forecast app, I have vc1 and vc2.
The JSON file to be parsed in vc2 exists for each country, and when the table view cell of vc1 is clicked, we try to implement parsing the JSON file of the country in vc2.
However, I do not know how to pass the JSON file name from vc1 to vc2 through segue.
When passing from vc1 to vc2 using segue, the variable is nil. Is there any solution?
Thanks for reading.
vc1
class MainViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var tableView: UITableView!
var countries = [Countries]()
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
let jsonDecoder = JSONDecoder()
guard let dataAsset = NSDataAsset(name: "countries")
else {
return
}
do {
countries = try jsonDecoder.decode([Countries].self, from: dataAsset.data)
} catch {
print(error.localizedDescription)
}
tableView.reloadData()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return countries.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MainCell", for: indexPath)
let country: Countries = countries[indexPath.row]
cell.imageView?.image = UIImage(named: "flag_" + country.asset_name)
cell.textLabel?.text = country.korean_name
return cell
}
// Data Transfer
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let nextViewController: SecondViewController = segue.destination as? SecondViewController else {
return
}
guard let cell: UITableViewCell = sender as? UITableViewCell else {
return
}
func name(indexPath: IndexPath) {
let country: Countries = countries[indexPath.row]
nextViewController.title = cell.textLabel?.text
nextViewController.secondAssetName = country.asset_name
}
}
}
vc2
class SecondViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
var weathers = [Weather]()
var secondAssetName: String?
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.delegate = self
self.tableView.dataSource = self
let jsonDecoder = JSONDecoder()
guard let dataAsset = NSDataAsset(name: secondAssetName ?? " ") else {
return
}
do {
weathers = try jsonDecoder.decode([Weather].self, from: dataAsset.data)
} catch {
print(error.localizedDescription)
}
tableView.reloadData()
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return weathers.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell: CustomTableViewCell = tableView.dequeueReusableCell(withIdentifier: "CustomCell", for: indexPath) as! CustomTableViewCell
let weather: Weather = weathers[indexPath.row]
switch weather.state {
case 10:
cell.cellImageView?.image = UIImage(named: "sunny.png")
case 11:
cell.cellImageView?.image = UIImage(named: "cloudy.png")
case 12:
cell.cellImageView?.image = UIImage(named: "rainy.png")
case 13:
cell.cellImageView?.image = UIImage(named: "snowy.png")
default:
return cell
}
cell.cityNameLabel.text = weather.city_name
cell.temperatureLabel.text = String(weather.celsius)
cell.rainfallProbabilityLabel.text = String(weather.rainfall_probability)
return cell
}
}

Answer 1

In VC1, when do you navigate to VC2?
If you have connected the VC1 and VC2 in the storyboard please remove that.
You need to call the "performSegueWithIdentifier" method when the user selects a cell.
For this, you need to implement tableview's didSelectRowAtIndexPath. In this method, you need to call the performSegueWithIdentier method to navigate to vc2.
Also,
In the prepare for segue method, you have this code.
func name(indexPath: IndexPath) {
let country: Countries = countries[indexPath.row]
nextViewController.title = cell.textLabel?.text
nextViewController.secondAssetName = country.asset_name
}
Why do you have it as function? and you are not calling the name function here?
You can move the following code outside the name(index path:) function.
Like so :
// Data Transfer
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard let nextViewController: SecondViewController = segue.destination as? SecondViewController else {
return
}
guard let cell: UITableViewCell = sender as? UITableViewCell else {
return
}
let country: Countries = countries[indexPath.row]
nextViewController.title = cell.textLabel?.text
nextViewController.secondAssetName = country.asset_name
}