将数据从gui类获取到另一个类

Question

我有这个项目应该从GUI获取信息并执行计算，但似乎数据只返回null值，我很难理解如何定制setter和getter使用GUI。这是我的GUI类：

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

class InfoGUI extends JFrame {
    private JButton btnOK = new JButton("OK");
    private JButton btnCancel = new JButton("Cancel");

    private JTextField txtCustomerName = new JTextField();
    private JTextField txtCustomerNumber = new JTextField();
    private JTextField txtCreditLimit = new JTextField();
    private JTextField txtPrevBalance = new JTextField();
    private JTextField txtCurrentPurchases = new JTextField();
    private JTextField txtPayments = new JTextField();
    private JTextField txtCreditsReturns = new JTextField();
    private JTextField txtLatefeeds = new JTextField();

    private JLabel lblCustomerName = new JLabel("Name :");
    private JLabel lblCustomerNumber = new JLabel("Number :");
    private JLabel lblCreditLimit = new JLabel("Credit Limit :");
    private JLabel lblPrevbalance = new JLabel("Previous Balance :");
    private JLabel lblCurrentPurchases = new JLabel("Current Purchases :");
    private JLabel lblPayments = new JLabel("Payments :");
    private JLabel lblCreditsReturns = new JLabel("Credits/Returns :");
    private JLabel lblLateFees = new JLabel("Late Fees :");

    public InfoGUI() {
        this.name = null;
        setTitle("Credit Wizard");
        setSize(300, 375);
        setLayout(null);
        setResizable(false);

        initComponent();
        initEvent();
    }
    private void initComponent() {
        btnOK.setBounds(20, 300, 80, 25);
        btnCancel.setBounds(110, 300, 80, 25);

        txtCustomerName.setBounds(100, 10, 100, 20);
        txtCustomerNumber.setBounds(100, 35, 100, 20);
        txtCreditLimit.setBounds(100, 65, 100, 20);
        txtPrevBalance.setBounds(130, 95, 100, 20);
        txtCurrentPurchases.setBounds(135, 125, 100, 20);
        txtPayments.setBounds(100, 155, 100, 20);
        txtCreditsReturns.setBounds(120, 185, 100, 20);
        txtLatefeeds.setBounds(100, 215, 100, 20);

        lblCustomerName.setBounds(20, 10, 100, 20);
        lblCustomerNumber.setBounds(20, 35, 100, 20);
        lblCreditLimit.setBounds(20, 65, 100, 20);
        lblPrevbalance.setBounds(20, 95, 120, 20);
        lblCurrentPurchases.setBounds(20, 125, 125, 20);
        lblPayments.setBounds(20, 155, 100, 20);
        lblCreditsReturns.setBounds(20, 185, 120, 20);
        lblLateFees.setBounds(20, 215, 100, 20);

        add(btnOK);
        add(btnCancel);

        add(lblCustomerName);
        add(lblCustomerNumber);
        add(lblCreditLimit);
        add(lblPrevbalance);
        add(lblCurrentPurchases);
        add(lblPayments);
        add(lblCreditsReturns);
        add(lblLateFees);

        add(txtCustomerName);
        add(txtCustomerNumber);
        add(txtCreditLimit);
        add(txtPrevBalance);
        add(txtCurrentPurchases);
        add(txtPayments);
        add(txtCreditsReturns);
        add(txtLatefeeds);
    }
    private void initEvent() {

        this.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                System.exit(1);
            }
        });

        btnCancel.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                btnCancelClick(e);
            }
        });

        btnOK.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                btnOKClick(e);
            }
        });
    }
    private void btnCancelClick(ActionEvent evt) {
        System.exit(0);
    }
    private String name;
    private double custNum;
    private double creditLimit;
    private double prevBalance;
    private double currentPurchases;
    private double payments;
    private double creditsReturns;
    private double lateFees;
    private void btnOKClick(ActionEvent evt) {
        try {
            String name = (txtCustomerName.getText());
            custNum = Double.parseDouble(txtCustomerNumber.getText());
            creditLimit = Double.parseDouble(txtCreditLimit.getText());
            prevBalance = Double.parseDouble(txtPrevBalance.getText());
            currentPurchases = Double.parseDouble(txtPrevBalance.getText());
            payments = Double.parseDouble(txtPayments.getText());
            creditsReturns = Double.parseDouble(txtCreditsReturns.getText());
            lateFees = Double.parseDouble(txtLatefeeds.getText());
            creditInfoSystem calc = new creditInfoSystem();
            calc.buttonClick();
            System.exit(0);
        } catch (Exception e) {
            System.out.println(e);
            JOptionPane.showMessageDialog(null,
                e.toString(),
                "Error",
                JOptionPane.ERROR_MESSAGE);
        }
    }
    public void creditFields(String newName, double newCustNum, double newCreditLimit,
        double newPrevBalance, double newCurrentPurchases, double newPayments,
        double newCreditsReturns, double newLateFees) {
        setName(newName);
        setCustNum(newCustNum);
        setCreditLimit(newCreditLimit);
        setPrevBalance(newPrevBalance);
        setCurrentPurchases(newCurrentPurchases);
        setPayments(newPayments);
        setCreditsReturns(newCreditsReturns);
        setLateFees(newLateFees);
    }
    public void setName(String newName) {
        name = newName;
    }
    public String getName() {
        return name;
    }
    public void setCustNum(double newCustNum) {
        custNum = newCustNum;
    }
    public double getCustNum() {
        return custNum;
    }
    public void setCreditLimit(double newCreditLimit) {
        creditLimit = newCreditLimit;
    }
    public double getCreditLimit() {
        return creditLimit;
    }
    public void setPrevBalance(double newPrevBalance) {
        prevBalance = newPrevBalance;
    }
    public double getPrevBalance() {
        return prevBalance;
    }
    public void setCurrentPurchases(double newCurrentPurchases) {
        currentPurchases = newCurrentPurchases;
    }
    public double getCurrentPurchases() {
        return currentPurchases;
    }
    public void setPayments(double newPayments) {
        payments = newPayments;
    }
    public double getPayments() {
        return payments;
    }
    public void setCreditsReturns(double newCreditsReturns) {
        creditsReturns = newCreditsReturns;
    }
    public double getCreditsReturns() {
        return creditsReturns;
    }
    public void setLateFees(double newLateFees) {
        lateFees = newLateFees;
    }
    public double getLateFees() {
        return lateFees;
    }
}

而我的主要课程：

public class CreditInfoSystem {
    public static void main(String[] args) {
        InfoGUI f = new InfoGUI();
        f.setVisible(true);
    }
    public static void buttonClick() {
        InfoGUI get = new InfoGUI();
        String custName = get.getName();
        double custNum = get.getCustNum();
        double creditLimit = get.getCreditLimit();
        double prevBalance = get.getPrevBalance();
        double currentPurchases = get.getCurrentPurchases();
        double payments = get.getPayments();
        double creditsReturns = get.getCreditsReturns();
        double lateFees = get.getLateFees();
        System.out.println(custName);
    }
}

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