第5周作业-贷款计算器程序

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;

public class LoanCalculator  extends JFrame {
private JTextField jtfAnnualInterestRate = new JTextField();
private JTextField jtfNumberofYears = new JTextField();
private JTextField jtfLoanAmount = new JTextField();
private JTextField jtfMonthlyPayment = new JTextField();
private JTextField jtfTotalPayment = new JTextField();

private JButton jbtComputeLoan = new JButton("Compute Payment");

public LoanCalculator() {

JPanel p1 = new JPanel(new GridLayout(5,2));
p1.add(new JLabel("Annual Interest Rate"));
p1.add(jtfAnnualInterestRate);
p1.add(new JLabel("Number of Years"));
p1.add(jtfNumberofYears);
p1.add(new JLabel("Loan Amount"));
p1.add(jtfLoanAmount);
p1.add(new JLabel("Monthly Payment"));
p1.add(jtfMonthlyPayment);
p1.add(new JLabel("Total Payment"));
p1.add(jtfTotalPayment);
p1.setBorder(new TitledBorder("Enter loan amout,interest rate,and year"));

JPanel p2 = new JPanel(new FlowLayout(FlowLayout.RIGHT));
p2.add(jbtComputeLoan);
add(p1,BorderLayout.CENTER);
add(p2,BorderLayout.SOUTH);

jbtComputeLoan.addActionListener(new ButtonListener());
}
private class ButtonListener implements ActionListener {
public void actionPerformed(ActionEvent e ) {

double interest = Double.parseDouble(jtfAnnualInterestRate.getText());
int year =
Integer.parseInt(jtfNumberofYears.getText());
Double .parseDouble(jtfLoanAmount.getText());
Loan loan = new Loan (interest,year,loanAmount);
//Loan loan = new Loan(interest,year,loanAmount);

jtfMonthlyPayment.setText(String.format("%.2f",loan.getMonthlyPayment()));
jtfTotalPayment.setText(String.format("%.2f",loan.getTotalPayment()));

}
}
public static void main(String[] args){
LoanCalculator frame = new LoanCalculator();
frame.pack();
frame.setTitle("LoanCaculator");
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}

}