Simple java fxml app fix

I have simple java fxml app that have multiple : First the progress bar isn’t working until thread loop completed while I want it to work while the loop work . Second the export button export button don’t ask user where he want to export the data it hangs and that only in Mac not in windows SO U MUST HAVE A MAC TO UNDERSTAND. Third the check and recheck buttons should be separated because now it’s working from same handler And fourth I want user when enter a number and press enter ,he should have pop up with 3 buttons every button send the number entered to specific url with the button name as extra value and then the 3 buttons windows disappear. And user can enter new number