如何让我的Java GUI正确地计算字段？

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

public class CalculatorGUI extends JFrame {
    private JTextField textField1;
    private JTextField textField2;
    private JButton calculateButton;
    private JLabel resultLabel;

    public CalculatorGUI() {
        setTitle("Calculator");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(300, 200);
        setLayout(new FlowLayout());

        textField1 = new JTextField(10);
        textField2 = new JTextField(10);
        calculateButton = new JButton("Calculate");
        resultLabel = new JLabel();

        calculateButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                // 获取用户输入的数据
                String input1 = textField1.getText();
                String input2 = textField2.getText();

                try {
                    // 数据转换与计算
                    double num1 = Double.parseDouble(input1);
                    double num2 = Double.parseDouble(input2);
                    double result = num1 + num2;

                    // 显示计算结果
                    resultLabel.setText("Result: " + result);
                } catch (NumberFormatException ex) {
                    // 处理非法输入的异常情况
                    resultLabel.setText("Invalid input");
                }
            }
        });

        add(textField1);
        add(textField2);
        add(calculateButton);
        add(resultLabel);

        setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new CalculatorGUI();
            }
        });
    }
}