"Fundamentals of Java language Programming"--event-driven programming--loan calculator

Enter the total amount of the year interest rate to calculate the monthly repayment number of the total repayment

Package Chapter16;import Java.awt.borderlayout;import Java.awt.flowlayout;import java.awt.gridlayout;import Java.awt.event.actionevent;import Java.awt.event.actionlistener;import Javax.swing.jbutton;import Javax.swing.jframe;import Javax.swing.jlabel;import Javax.swing.jpanel;import Javax.swing.JTextField;//import Javax.swing.border.TitledBorder, @SuppressWarnings ("Serial") public class Loancalculator extends Jframe{private JTextField annualinterestrate = new JTextField ();p rivate JTextField numberofyears = new JTextField ();p rivate JTextField L Oanamount = new JTextField ();p rivate JTextField monthlypayment = new JTextField ();p rivate JTextField TotalPayment = new JT Extfield ();p ublic loancalculator () {JPanel P1 = new JPanel ();p 1.setLayout (New GridLayout (5,2));p 1.add (New JLabel (" Annual interest rate "));p 1.add (annualinterestrate);p 1.add (New JLabel (" Number of years ");p 1.add (numberofyears); P1.add (New JLabel ("loan Amount"));p 1.add (loanamount);p 1.add (New JLabel ("Monthly Payment"));p 1.add (Monthlypayment);p 1.add (New JLabel ("Totalpayment"));p 1.add (totalpayment);p 1.setBorder (New Titledborder ("Enter loan amount, Interest Rate,and Year ")); JPanel P2 = new JPanel ();p 2.setLayout (New FlowLayout (flowlayout.right)); JButton button = new JButton ("Computer payment");p 2.add (Button,borderlayout.south); add (p1,borderlayout.center);// Need to add an orientation add (P2,borderlayout.south); Button.addactionlistener (new Buttonlistener ());} public static void Main (string[] args) {JFrame frame = new Loancalculator (); Frame.settitle ("Loancalculator"); Frame.setdefaultcloseoperation (Jframe.exit_on_close); Frame.setlocationrelativeto (null); Frame.setVisible (true); Frame.pack (); Frame.setsize (300, 300);} Class Buttonlistener implements actionlistener{@Overridepublic void actionperformed (ActionEvent e) {Double interest = Double.parsedouble (Annualinterestrate.gettext ());d ouble loanamount = double.parsedouble (LoanAmount.getText ()); int Year = Integer.parseint (Numberofyears.gettext ()); Loan Loan = new Loan (interest,year,loanamount); MonthlyPayment.settext (String.Format ("%.2f", Loan.getmonthlypayment ()));//why is no useful on line 61?? Totalpayment.settext (String.Format ("%.2f", Loan.gettotalpayment ());}}}  Class Loan {private Double annualinterestrate;  private int numberofyears;  Private double loanamount;  Private Java.util.Date loandate;  /** Default Constructor */Public Loan () {This (2.5, 1, 1000); }/** Construct a loan with specified annual interest rate, number of years and loan amount */public loan (Doub    Le annualinterestrate, int numberofyears, double loanamount) {this.annualinterestrate = annualinterestrate;    This.numberofyears = Numberofyears;    This.loanamount = Loanamount;  Loandate = new Java.util.Date ();  }/** return annualinterestrate */public double getannualinterestrate () {return annualinterestrate; }/** Set a new annualinterestrate */public void setannualinterestrate (double annualinterestrate) {This.annualinter  Estrate = annualinterestrate; }/** Return NuMberofyears */public int getnumberofyears () {return numberofyears; }/** Set a new numberofyears */public void setnumberofyears (int numberofyears) {this.numberofyears = Numberofyears  ;  }/** return Loanamount */public double Getloanamount () {return loanamount;  }/** Set a newloanamount */public void Setloanamount (double loanamount) {this.loanamount = Loanamount; }/** Find Monthly payment */public double getmonthlypayment () {Double monthlyinterestrate = ANNUALINTERESTRATE/1    200; Double monthlypayment = Loanamount * Monthlyinterestrate/(1-(Math.pow (1/(1 + monthlyinterestrate), numberofyear    S * 12)));      return monthlypayment; }/** Find Total payment */public double gettotalpayment () {Double totalpayment = getmonthlypayment () * Numberofyea    RS * 12;      return totalpayment;  }/** return Loan date */public java.util.Date getloandate () {return loandate; }}

Click Computer payment to generate the data

"Fundamentals of Java language Programming"--event-driven programming--loan calculator