Index out of range Outside Function of Alamofire Swift - arrays

Question

I don't get when I call the let item = stationData[0] it says that its index is out of range... But inside my Alamofire request it returns that it has data...
Below is my code.
my alamofire is inside the viewdid load.
Alamofire.request(url, method: .post, parameters: parameters, encoding: JSONEncoding.default).responseJSON {
responseData in
if responseData.result.value != nil {
let swiftyJson = JSON(responseData.result.value as Any)
if let data = swiftyJson["data"].arrayObject as? [[String: Any]] {
if data.isEmpty{
print("NO DATA FOUND")
}
else {
self.stationData = data.map(StationData.init)
}
}
}
}
Here is my code where I use stationData
extension ParameterViewController: UICollectionViewDataSource {
func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
switch itemType {
case .items:
return parameterName1.count
case .items1:
return parameterName2.count
case .items2:
return parameterName3.count
default:
print("No count to get")
}
}
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ValuesViewCell", for: indexPath) as! ValuesViewCell
let item = stationData[0]
switch itemType {
case .items:
cell.setData(parameterName: self.parameterName1[indexPath.row], parameterValue: item.vakue1)
case .items1:
cell.setData(parameterName: self.parameterName2[indexPath.row], parameterValue: item.value2)
case .items2:
cell.setData(parameterName: self.parameterName3[indexPath.row], parameterValue: item.value3)
default:
print("No cell to insert")
}
return cell
}
}

Answer 1

You should not access array directly by index if your array is not ready at the time of loading.
Instead of using
let item = stationData[0]
Try something like this
guard let item = stationData.first else {
return emptyCell
}
With this, you will always check if your array has the element.
Also you need to refresh the tableView when your data is ready from Alamofire.
Try this when you set stationData
else {
self.stationData = data.map(StationData.init)
self.tableView.reloadData()
}
Now, when your data is ready, tableView will reload and it will return proper cell with stationData's first element.