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Simple Java GUI Calculator that performs simple interest calculation.
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import java.awt.*; import java.awt.event.*; import java.awt.event.ActionListener; import javax.swing.*; import javax.swing.border.TitledBorder; public class ModifiedGUISimpleInterestCalculator extends JFrame { //create TextFields for principal, rate and time private JTextField principal = new JTextField(); private JTextField rate = new JTextField(); private JTextField time = new JTextField(); private JTextField simpleInterest = new JTextField(); // calculate JButton private JButton clear = new JButton("Clear"); private JButton calculate = new JButton("Calculate"); //private JButton clear = new JButton("Clear"); //create JTextArea JTextArea area = new JTextArea(1, 1); public ModifiedGUISimpleInterestCalculator() { // panel panel to hold labels and text fields JPanel panel1 = new JPanel(new GridLayout(5, 2)); panel1.add(new JLabel("Enter Principal")); panel1.add(principal); panel1.add(new JLabel("Enter Rate")); panel1.add(rate); panel1.add(new JLabel("Enter Time")); panel1.add(time); panel1.add(new JLabel("Simple Interest")); panel1.add(simpleInterest); panel1.setBorder(new TitledBorder("Enter Principal, Rate (as decimal e.g 0.1 for 10%) and Time.")); principal.setBorder(BorderFactory.createEtchedBorder()); rate.setBorder(BorderFactory.createEtchedBorder()); time.setBorder(BorderFactory.createEtchedBorder()); simpleInterest.setBorder(BorderFactory.createEtchedBorder()); simpleInterest.setEditable(false); simpleInterest.setForeground(Color.RED); // Panel p2 to hold the button JPanel panel2 = new JPanel(new FlowLayout(FlowLayout.RIGHT)); //panel2.add(clear); panel2.add(clear); panel2.add(calculate); // Add the panels to the frame add(panel1, BorderLayout.CENTER); add(panel2, BorderLayout.SOUTH); area.setForeground(Color.BLACK); area.setBackground(Color.WHITE); area.setLineWrap(true); area.setWrapStyleWord(true); area.setEditable(false); calculate.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { // Get values from text fields try { double amount = Double.parseDouble(principal.getText()); double rateOfInterest = Double.parseDouble(rate.getText()); double year = Double.parseDouble(time.getText()); String interest = "" + (amount * rateOfInterest * year); // Display simple interest simpleInterest.setText((interest)); } catch (Exception f) { JOptionPane.showMessageDialog(rootPane, "ERROR: " + (f.getMessage())); } String amountField = principal.getText(); String rateOfInterestField = rate.getText(); String yearField = time.getText(); if (e.getSource() == calculate) { if ("".equals(amountField) || "".equals(rateOfInterestField) || "".equals(yearField)) { String emptyFieldWarning; emptyFieldWarning = "One or more fields is/are empty!"; JOptionPane.showMessageDialog(rootPane, emptyFieldWarning); } } } }); clear.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { // Get values from text fields try { principal.setText(""); rate.setText(""); time.setText(""); simpleInterest.setText(""); } catch (Exception f) { } } }); } //create main method to run application public static void main(String[] args) { ModifiedGUISimpleInterestCalculator calculator = new ModifiedGUISimpleInterestCalculator(); calculator.setSize(360, 200); calculator.setTitle(" Simple Interest Calculator "); calculator.setResizable(false); calculator.setVisible(true); calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); } } |
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