I have a IBAction button which makes a calculation. In this IBAction, I want to implement an UIAlertController button where the user can press "OK" or "Cancel" to confirm a recalculation.
The Problem is that asap IBAction button is pressed, the calculation is done.

How can I make the function wait for UIAlertController response.

@IBAction func buttonCalculate(_ sender: UIButton) {
        
        let startDate = datePickerStart.date
        let endDate = datePikcerEnd.date
        // Calculate DAYS between start and end date
        var diff = Calendar.current.dateComponents([.day], from: startDate, to: endDate).day!
        //calculate ALL between start and end date
        var daily = 6
        diff  = 1
        daily = daily*diff
             
        // If "Calculate" button is pressed for recalculationhen 

       
            let emptyDiffCalcDaysLabel = diffCalcDaysLabel.text
            let emptyAmountLabel = allAmount.text
            
            if emptyDiffCalcDaysLabel != "-"  || emptyAmountLabel != "-"
            {
                let alertController = UIAlertController(title: "Attention", message: "Everything will be recalculated", preferredStyle: .alert)
                let defaultAction = UIAlertAction(title: "Ok", style: .default) {(ACTION) in print("OK")}
                let cancelAction = UIAlertAction(title: "Cancel", style: .cancel) {(ACTION) in print("Cancel")}
                
                alertController.addAction(defaultAction)
                alertController.addAction(cancelAction)
                self.present(alertController, animated: true)
            }
        
                     
          
        //Alert when negative value is calculated
        if diff < 1
        {
            let negativeDaysUIAlert = UIAlertController(title: "Attention", message: "Entered Date is invalid!", preferredStyle: .alert)
            negativeDaysUIAlert.addAction(UIAlertAction(title: "OK", style: .default))
            self.present(negativeDaysUIAlert, animated: true, completion: nil)
            // Show "-" instead of negative value
            diffCalcDaysLabel.text = "-"
            allAmount.text = "-"
        }
    }

CodePudding user response：

You need to put in the IBAction 'ok' callback, the code to recalculate (or a call the the function that recalculate).

Like that the recalculation is only done when the user click ok.