I have to create a program that will calculate the the average miles per tank and the cost to fill tank of a car. The inputs are tank capacity, miles per gallon, and price per gallon, the outputs are average miles per tank and cost to fill tank. I have to use the methods: getTankCapacity, getMpgRating, getGallonPrice, calculateAverageMiles, calculateFillCost, and displayOutput, and the inputs must also use try-catch. When I test the program leaving one of the text fields blank, the error message pops up multiple times and does not leave the output fields blank. I am unsure of how to fix this. Any help would be much appreciated!
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.*;
public class AverageMilesPerTank extends JFrame
{
Color black = new Color(0, 0, 0);
Color white = new Color(255, 255, 255);
Color light_gray = new Color(192, 192, 192);
JLabel tankCapacityJLabel;
JTextField tankCapacityJTextField;
JLabel mpgRatingJLabel;
JTextField mpgRatingJTextField;
JLabel gallonPriceJLabel;
JTextField gallonPriceJTextField;
JLabel averageMilesJLabel;
JTextField averageMilesJTextField;
JLabel fillCostJLabel;
JTextField fillCostJTextField;
JButton enterJButton;
JButton clearJButton;
JButton closeJButton;
DecimalFormat currency;
int tankCapacity;
double mpgRating;
double gallonPrice;
double averageMiles;
double fillCost;
public AverageMilesPerTank()
{
createUserInterface();
}
public void createUserInterface()
{
Container contentPane = getContentPane();
contentPane.setBackground(Color.white);
contentPane.setLayout(null);
tankCapacityJLabel = new JLabel();
tankCapacityJLabel.setBounds(50, 50, 120, 20);
tankCapacityJLabel.setFont(new Font("Default", Font.PLAIN, 12));
tankCapacityJLabel.setText("Tank Capacity");
tankCapacityJLabel.setForeground(black);
tankCapacityJLabel.setHorizontalAlignment(JLabel.LEFT);
contentPane.add(tankCapacityJLabel);
tankCapacityJTextField = new JTextField();
tankCapacityJTextField.setBounds(225, 50, 75, 20);
tankCapacityJTextField.setFont(new Font("Default", Font.PLAIN, 12));
tankCapacityJTextField.setHorizontalAlignment(JTextField.CENTER);
tankCapacityJTextField.setForeground(black);
tankCapacityJTextField.setBackground(white);
tankCapacityJTextField.setEditable(true);
contentPane.add(tankCapacityJTextField);
mpgRatingJLabel = new JLabel();
mpgRatingJLabel.setBounds(50, 80, 150, 20);
mpgRatingJLabel.setFont(new Font("Default", Font.PLAIN, 12));
mpgRatingJLabel.setText("Miles Per Gallon Rating");
mpgRatingJLabel.setForeground(black);
mpgRatingJLabel.setHorizontalAlignment(JLabel.LEFT);
contentPane.add(mpgRatingJLabel);
mpgRatingJTextField = new JTextField();
mpgRatingJTextField.setBounds(225, 80, 75, 20);
mpgRatingJTextField.setFont(new Font("Default", Font.PLAIN, 12));
mpgRatingJTextField.setHorizontalAlignment(JTextField.CENTER);
mpgRatingJTextField.setForeground(black);
mpgRatingJTextField.setBackground(white);
mpgRatingJTextField.setEditable(true);
contentPane.add(mpgRatingJTextField);
gallonPriceJLabel = new JLabel();
gallonPriceJLabel.setBounds(50, 110, 150, 20);
gallonPriceJLabel.setFont(new Font("Default", Font.PLAIN, 12));
gallonPriceJLabel.setText("Current Price Per Gallon");
gallonPriceJLabel.setForeground(black);
gallonPriceJLabel.setHorizontalAlignment(JLabel.LEFT);
contentPane.add(gallonPriceJLabel);
gallonPriceJTextField = new JTextField();
gallonPriceJTextField.setBounds(225, 110, 75, 20);
gallonPriceJTextField.setFont(new Font("Default", Font.PLAIN, 12));
gallonPriceJTextField.setHorizontalAlignment(JTextField.CENTER);
gallonPriceJTextField.setForeground(black);
gallonPriceJTextField.setBackground(white);
gallonPriceJTextField.setEditable(true);
contentPane.add(gallonPriceJTextField);
averageMilesJLabel = new JLabel();
averageMilesJLabel.setBounds(50, 170, 150, 20);
averageMilesJLabel.setFont(new Font("Default", Font.PLAIN, 12));
averageMilesJLabel.setText("Average Miles Per Tank");
averageMilesJLabel.setForeground(black);
averageMilesJLabel.setHorizontalAlignment(JLabel.LEFT);
contentPane.add(averageMilesJLabel);
averageMilesJTextField = new JTextField();
averageMilesJTextField.setBounds(225, 170, 75, 20);
averageMilesJTextField.setFont(new Font("Default", Font.PLAIN, 12));
averageMilesJTextField.setHorizontalAlignment(JTextField.CENTER);
averageMilesJTextField.setForeground(black);
averageMilesJTextField.setBackground(white);
averageMilesJTextField.setEditable(false);
contentPane.add(averageMilesJTextField);
fillCostJLabel = new JLabel();
fillCostJLabel.setBounds(50, 200, 150, 20);
fillCostJLabel.setFont(new Font("Default", Font.PLAIN, 12));
fillCostJLabel.setText("Cost to Fill Tank");
fillCostJLabel.setForeground(black);
fillCostJLabel.setHorizontalAlignment(JLabel.LEFT);
contentPane.add(fillCostJLabel);
fillCostJTextField = new JTextField();
fillCostJTextField.setBounds(225, 200, 75, 20);
fillCostJTextField.setFont(new Font("Default", Font.PLAIN, 12));
fillCostJTextField.setHorizontalAlignment(JTextField.CENTER);
fillCostJTextField.setForeground(black);
fillCostJTextField.setBackground(white);
fillCostJTextField.setEditable(false);
contentPane.add(fillCostJTextField);
enterJButton = new JButton();
enterJButton.setBounds(25, 300, 100, 20);
enterJButton.setFont(new Font("Default", Font.PLAIN, 12));
enterJButton.setText("Enter");
enterJButton.setForeground(black);
enterJButton.setBackground(white);
contentPane.add(enterJButton);
enterJButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
enterJButtonActionPerformed(event);
}
}
);
clearJButton = new JButton();
clearJButton.setBounds(150, 300, 100, 20);
clearJButton.setFont(new Font("Default", Font.PLAIN, 12));
clearJButton.setText("Clear");
clearJButton.setForeground(black);
clearJButton.setBackground(white);
contentPane.add(clearJButton);
clearJButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
clearJButtonActionPerformed(event);
}
}
);
closeJButton = new JButton();
closeJButton.setBounds(275, 300, 100, 20);
closeJButton.setFont(new Font("Default", Font.PLAIN, 12));
closeJButton.setText("Close");
closeJButton.setForeground(black);
closeJButton.setBackground(white);
contentPane.add(closeJButton);
closeJButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent event)
{
closeJButtonActionPerformed(event);
}
}
);
setTitle("Fuel Cost");
setSize(400, 400);
setVisible(true);
}
public static void main(String[] args)
{
AverageMilesPerTank application = new AverageMilesPerTank();
application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void enterJButtonActionPerformed(ActionEvent event)
{
//must list all methods here
tankCapacity = getTankCapacityInput();
mpgRating = getMpgRatingInput();
gallonPrice = getGallonPriceInput();
averageMiles = calculateAverageMiles();
fillCost = calculateFillCost();
displayOutput();
}
public int getTankCapacityInput()
{
try
{
tankCapacity = Integer.parseInt(tankCapacityJTextField.getText());
getMpgRatingInput();
}
catch(NumberFormatException exception)
{
JOptionPane.showMessageDialog(this,
"Please enter Tank Capacity!",
"Number Format Error", JOptionPane.ERROR_MESSAGE );
tankCapacityJTextField.setText("");
tankCapacityJTextField.requestFocusInWindow();
}
return tankCapacity;
}
public double getMpgRatingInput()
{
try
{
mpgRating = Double.parseDouble(mpgRatingJTextField.getText());
getGallonPriceInput();
}
catch(NumberFormatException exception)
{
JOptionPane.showMessageDialog(this,
"Please enter Miles Per Gallon Rating!",
"Number Format Error", JOptionPane.ERROR_MESSAGE );
mpgRatingJTextField.setText("");
mpgRatingJTextField.requestFocusInWindow();
}
return mpgRating;
}
public double getGallonPriceInput()
{
try
{
gallonPrice = Double.parseDouble(gallonPriceJTextField.getText());
calculateFillCost();
}
catch(NumberFormatException exception)
{
JOptionPane.showMessageDialog(this,
"Please enter Current Price Per Gallon!",
"Number Format Error", JOptionPane.ERROR_MESSAGE );
gallonPriceJTextField.setText("");
gallonPriceJTextField.requestFocusInWindow();
}
return gallonPrice;
}
public double calculateAverageMiles()
{
averageMiles = mpgRating * tankCapacity;
return averageMiles;
}
public double calculateFillCost()
{
currency = new DecimalFormat("$0.00");
fillCost = tankCapacity * gallonPrice;
return fillCost;
}
public void displayOutput()
{
averageMilesJTextField.setText("" + averageMiles);
fillCostJTextField.setText("" + currency.format(fillCost));
}
public void clearJButtonActionPerformed(ActionEvent event)
{
tankCapacityJTextField.setText("");
tankCapacityJTextField.requestFocusInWindow();
mpgRatingJTextField.setText("");
gallonPriceJTextField.setText("");
averageMilesJTextField.setText("");
fillCostJTextField.setText("");
}
public void closeJButtonActionPerformed(ActionEvent event)
{
System.exit(0);
}
}
