Alert view controller not presented once API call successfully completed SWIFT - ios

Question

I have the following API call:
func updateSheetVals() {
let args = ["id": viewModel.id]
let measurements = UpdateRequest.Measurements(
departure: Double(sheet.postRefuelQuantity.field.currentValue),
discrepancy: Double(sheet.discrepancy.field.currentValue),
discrepancyPercentage: Double(sheet.discrepancyPercent.field.currentValue),
preTotal: Double(dheet.preTotal.field.currentValue),
targetTotal: Double(fuelSheet.requiredTotal.field.currentValue)
)
let body = UpdateRequest(measurement: measurements)
API.client.post(.updateFuelSheetVals, with: args, using: .put, posting: body, expecting: MessageResponse.self) { (success, response) in
switch success {
case .failure:
print("Check network connection")
case .success:
DispatchQueue.asyncMain {
self.present(WarningViewController.finished(), animated: true)
}
}
}
}
}
And yet, even though I receive a 200 response and the API is called correctly, my view controller is never displayed. Happy to provide more contextual code if needed, but wondered firstly if I'm just missing something obvious with this block...
EDIT:
The API call is triggered in the following code:
func acceptButtonPressed(_ button: Button) {
var confirmation: UIViewController & ConfirmationAction
guard let level = viewModel.getSelectedSheet().order.levelDouble else { return }
if self.viewModel.requiresSignature {
if level < 3 {
confirmation = SignatureViewController(hasDiscrepancy: viewModel.hasDiscrepancy, discrepancyPrompt: viewModel.discrepancyPrompt, sl: level)
} else {
confirmation = SignatureViewController(hasDiscrepancy: viewModel.hasDiscrepancy,
discrepancyPrompt: viewModel.discrepancyPrompt, sl: level)
}
} else {
if let userInputAllowed = sheet.userInputAllowed, level < 3, !userInputAllowed {
confirmation = OrderAcceptAlertViewController.alert()
} else if level < 3 {
confirmation = DiscrepancyAlertViewController.alertWithDiscrepancy(hasDiscrepancy: viewModel.hasDiscrepancy,
discrepancyPrompt: viewModel.discrepancyFromManualInput(discrepancyValue: fuelSheet.percentageDiscrepancy.field.currentValue))
} else {
confirmation = DiscrepancyAlertViewController.alertWithDiscrepancy(hasDiscrepancy: viewModel.hasDiscrepancy,
discrepancyPrompt: viewModel.discrepancyPrompt)
}
}
confirmation.confirmationAction = { [weak confirmation, weak self] response in
guard let self = self else {
return
}
var completedSignature: SignatureParameter?
switch response {
case let .signature(signature):
completedSignature = signature
case .discrepancy:
break
}
let args = ["id": self.viewModel.id]
let params = AcceptParameter(
employee: self.viewModel.employee,
signature: completedSignature,
base64FuelSheet: self.sheet.ticket?.base64
)
if let confirm = confirmation {
confirm.setLoading(true)
API.client.post(.accept, with: args, using: .put, posting: params, expecting: Nothing.self, completion: { [weak self] (success, _) in
DispatchQueue.asyncMain {
guard let self = self else {
return
}
confirm.setLoading(false)
self.navigationController?.popViewController(animated: true)
}
}
})
self.updateSheetVals()
}
}
present(confirmation, animated: true, completion: nil)
}

Answer 1

For this
self.navigationController?.popViewController(animated: true)
to work the vc must be inside a navigation controller and if not this self.navigationController? will be nil and nothing will show , you either need a segue/push.present like
self.present(viewController, animated: true, completion: nil)

Answer 2

This will work for sure:
case .success:
DispatchQueue.asyncMain {
let viewController = self.storyboard?.instantiateViewController(withIdentifier: WarningViewController) as! WarningViewController
self.present(viewController, animated: true, completion: nil)
}
}