需要帮忙。(Need help. Im trying to create a combobox and some textfields for a class project on taxable income)

 我正在为CS类创建一个税务项目。 我正在使用netbeans。 我的项目完全正常工作，除了我总是得到的税收返回值是0.0。 我是Java新手。 我认为问题出在我的“收入”变量的某个地方。 用户输入他们的应税收入，我取用户输入的字符串并将其解析为整数并称之为“收入”。 然后程序检查“收入”以查看它是否大于或小于某些值，以查看用户所在的税率范围。税率范围受用户组合框选择“填充状态”的影响。 到目前为止，我的程序只有最小的税率和单一的填充状态用于调试目的...一旦我得到这个代码工作，我应该能够相当容易地填写其余部分。 我想知道是否有人可以查看代码，看看它是什么我错过了。 我很难将组合框与用户jtextfield条目连接起来进行计算。 我不确定我的问题是在我的数组中，在我的“收入”变量中，还是在其他地方。 我花了很多时间浏览书籍和java教程。 如果您可以一瞥并提供帮助，那将不胜感激:) 
 
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class IncomeTax2 extends JFrame implements ItemListener
{

    private JTextField jtfIncome;
    private JTextField jtfTax;
    private JButton jbCalculate;
    private JComboBox jcb;
    private JLabel info;
    private String[] fsChoice =
    {
        "", "Single", "Married filing jointly", "Married filing separately",
        "Head of Household"
    };
    int income;
    double tax;
    private String fillingStatus;

    public static void main(String[] args)
    {
        JFrame frame = new IncomeTax2();
        frame.pack();
        frame.setTitle("Income Tax Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public IncomeTax2()
    {
        JPanel p = new JPanel();
        p.setLayout(new GridLayout(3, 2, 5, 5));
        p.setBorder(new EmptyBorder(5, 5, 5, 5));
        p.add(jcb = new JComboBox(fsChoice));
        p.add(jtfIncome = new JTextField(8));
        p.add(info = new JLabel("Pick filling status and "
                + "enter taxable income"));
        p.add(jbCalculate = new JButton("Calculate"));
        p.add(jtfTax = new JTextField(16));
        jtfTax.setEditable(false);
        setLayout(new BorderLayout());
        jtfTax.setHorizontalAlignment(JTextField.RIGHT);
        add(p, BorderLayout.CENTER);

        jtfIncome.addKeyListener(new KeyAdapter()
        {
            public void keyTyped(KeyEvent e)
            {
                char c = e.getKeyChar();
                if (!(Character.isDigit(c) || (c == KeyEvent.VK_BACK_SPACE) || 
                        c == KeyEvent.VK_DELETE || c == KeyEvent.VK_ENTER))
                {
                    Toolkit.getDefaultToolkit().beep();
                    System.out.println("User must enter a digit.");
                    e.consume();
                }
            }
        });

        jcb.addItemListener(this);

        jbCalculate.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                calculate();
            }
        });

         jtfIncome.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String inputStr = jtfIncome.getText();
                income = Integer.parseInt(inputStr);
            }
        });
    }

    public void itemStateChanged(ItemEvent e)
    {
        if (e.getStateChange() == ItemEvent.SELECTED)
        {
            fillingStatus = (String) jcb.getSelectedItem();
            switch (fillingStatus)
            {
                case "Single":
                    if (income <= 8350)
                    {
                        tax = income * 0.10;
                        System.out.println("case[1]");
                        System.out.println("Tax = " + tax);
                    }
                    ;
                    break;
            }
        }
    }

    public void calculate()
    {
        jtfTax.setText(((int)(tax * 100) / 100.0 + ""));
    }

}

I'm creating a tax project for a CS class. Im working with netbeans. My project is working entirely except for the fact that the return value I always get for the tax is 0.0 . I am new to Java. I think that the problem lies somewhere with my "income" variable. The user inputs their taxable income, I take that string the user entered and parse it into an integer and call it "income". The program then checks the "income" to see if it is greater or less than certain values to see what tax bracket the user is in. The tax bracket is affected by the user's combobox choice for "filling status". So far my program only has the smallest tax bracket and the filling status of single for debugging purposes... once i get this code working I should be able to fill in the rest fairly easily. I'm wondering if anyone can look over the code and see what it is I'm missing. Im having a hard time connecting the combobox with the user jtextfield entry to make a calculation. Im not sure if my problem lies in my array, in my "income" variable, or somewhere else. I've spent a ton of time looking through books and java tutorials. If you can take a glance and help, that would be appreciated :)
 
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.border.EmptyBorder;

public class IncomeTax2 extends JFrame implements ItemListener
{

    private JTextField jtfIncome;
    private JTextField jtfTax;
    private JButton jbCalculate;
    private JComboBox jcb;
    private JLabel info;
    private String[] fsChoice =
    {
        "", "Single", "Married filing jointly", "Married filing separately",
        "Head of Household"
    };
    int income;
    double tax;
    private String fillingStatus;

    public static void main(String[] args)
    {
        JFrame frame = new IncomeTax2();
        frame.pack();
        frame.setTitle("Income Tax Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    public IncomeTax2()
    {
        JPanel p = new JPanel();
        p.setLayout(new GridLayout(3, 2, 5, 5));
        p.setBorder(new EmptyBorder(5, 5, 5, 5));
        p.add(jcb = new JComboBox(fsChoice));
        p.add(jtfIncome = new JTextField(8));
        p.add(info = new JLabel("Pick filling status and "
                + "enter taxable income"));
        p.add(jbCalculate = new JButton("Calculate"));
        p.add(jtfTax = new JTextField(16));
        jtfTax.setEditable(false);
        setLayout(new BorderLayout());
        jtfTax.setHorizontalAlignment(JTextField.RIGHT);
        add(p, BorderLayout.CENTER);

        jtfIncome.addKeyListener(new KeyAdapter()
        {
            public void keyTyped(KeyEvent e)
            {
                char c = e.getKeyChar();
                if (!(Character.isDigit(c) || (c == KeyEvent.VK_BACK_SPACE) || 
                        c == KeyEvent.VK_DELETE || c == KeyEvent.VK_ENTER))
                {
                    Toolkit.getDefaultToolkit().beep();
                    System.out.println("User must enter a digit.");
                    e.consume();
                }
            }
        });

        jcb.addItemListener(this);

        jbCalculate.addActionListener(new ActionListener()
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                calculate();
            }
        });

         jtfIncome.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e)
            {
                String inputStr = jtfIncome.getText();
                income = Integer.parseInt(inputStr);
            }
        });
    }

    public void itemStateChanged(ItemEvent e)
    {
        if (e.getStateChange() == ItemEvent.SELECTED)
        {
            fillingStatus = (String) jcb.getSelectedItem();
            switch (fillingStatus)
            {
                case "Single":
                    if (income <= 8350)
                    {
                        tax = income * 0.10;
                        System.out.println("case[1]");
                        System.out.println("Tax = " + tax);
                    }
                    ;
                    break;
            }
        }
    }

    public void calculate()
    {
        jtfTax.setText(((int)(tax * 100) / 100.0 + ""));
    }

}

原文：https://stackoverflow.com/questions/22493102