java - 单选按钮组和额外选项

Question

所以我的 Java 程序有问题。我目前希望它有 3 种主菜选项，汉堡包、披萨和沙拉以及附加选项。现在，该程序从选择的汉堡包开始，并且他们还会计算可用的附加组件的价格。选择主项目后，附加选项应随新项目而更改，但事实并非如此。我已经盯着这个问题有一段时间了，所以可能是我错过了一些非常简单的东西，比如清理该区域，然后显示新的附加选项。无论如何，我们将不胜感激，这是当前的代码。

import java.awt.*;
import javax.swing.*;
import java.text.DecimalFormat;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonGroup;
import javax.swing.JRadioButton;


public class LunchOrder extends JFrame {

    private JRadioButton hamburgerJButton, pizzaJButton, saladJButton;
    private JCheckBox lettuceButton, mayonnaiseButton, mustardButton, pepperoniButton,
            sausageButton, mushroomsButton, croutonsButton, baconBitsButton, breadSticksButton;
    private JLabel subTotal, tax, totalDue;
    private JTextField subTotalText, taxText, totalDueText;
    private JButton placeOrder, clearOrder, exitButton;

   // no-argument constructor
   public LunchOrder()
   {
      createUserInterface();
   }

   // create and position GUI components; register event handlers
   private void createUserInterface()
   {
      // get content pane for attaching GUI components
      Container contentPane = getContentPane();

      // enable explicit positioning of GUI components
      contentPane.setLayout( null);

      hamburgerJButton = new JRadioButton("Hamburger - $6.95" );
      hamburgerJButton.setSelected(true);

      pizzaJButton = new JRadioButton("Pizza - $5.95");
      pizzaJButton.setSelected(false);
      saladJButton = new JRadioButton("Salad - $4.95");
      saladJButton.setSelected(false);
      ButtonGroup bgroup = new ButtonGroup();
      bgroup.add(hamburgerJButton);
      bgroup.add(pizzaJButton);
      bgroup.add(saladJButton);

      JPanel mainCourse = new JPanel();
      mainCourse.setLayout( new GridLayout( 3, 1 ));
      mainCourse.setBounds( 10, 10, 150,135 );
      mainCourse.add(hamburgerJButton);
      mainCourse.add(pizzaJButton);
      mainCourse.add(saladJButton);
      mainCourse.setBorder(BorderFactory.createTitledBorder(
              BorderFactory.createEtchedBorder(), "Main course" ) );
      //contentPane.add( mainCourseJPanel, BorderLayout.NORTH );
      contentPane.add( mainCourse );
       //Add action listener to created button

      //JCheckBox

      lettuceButton = new JCheckBox("Lettuce, tomato, and onions");
      lettuceButton.setSelected(true);

      mayonnaiseButton= new JCheckBox("Mayonnaise");
      mayonnaiseButton.setSelected(false);

      mustardButton = new JCheckBox("Mustard");
      mustardButton.setSelected(true);

      pepperoniButton = new JCheckBox("Pepperoni");
      sausageButton= new JCheckBox("Sausage");
      mushroomsButton = new JCheckBox("Mushrooms");
      croutonsButton = new JCheckBox("Croutons");
      baconBitsButton= new JCheckBox("Bacon bits");
      breadSticksButton = new JCheckBox("Bread sticks");

      //JPanel addons
      JPanel addOns = new JPanel();
      GridLayout addOnGlay = new GridLayout(3,3);
      addOns.setLayout(addOnGlay);
      addOns.setBounds( 250, 10, 250, 135 );
      addOns.add(lettuceButton);
      addOns.add(pepperoniButton);
      addOns.add(croutonsButton);
      addOns.add(mayonnaiseButton);
      addOns.add(sausageButton);
      addOns.add(baconBitsButton);
      addOns.add(mustardButton);
      addOns.add(mushroomsButton);
      addOns.add(breadSticksButton);

      pepperoniButton.setVisible(false);
      sausageButton.setVisible(false);
      mushroomsButton.setVisible(false);
      croutonsButton.setVisible(false);
      baconBitsButton.setVisible(false);
      breadSticksButton.setVisible(false);

      addOns.setBorder(BorderFactory.createTitledBorder(
              BorderFactory.createEtchedBorder(), "Add ons($.25/each)" ) );
      contentPane.add( addOns );

      // subtotal JLabel
      subTotal = new JLabel();
      subTotal.setBounds(10, 110, 100, 200);
      contentPane.add(subTotal);
      subTotal.setText( "Subtotal: " );
      subTotal.setHorizontalAlignment(JLabel.RIGHT);

      // subtotal JTextField
      subTotalText = new JTextField();
      subTotalText.setBounds(115, 200, 80, 22);
      subTotalText.setHorizontalAlignment(JTextField.LEFT);
      contentPane.add(subTotalText);

      // Tax JLabel
      tax = new JLabel();
      tax.setBounds(10, 135, 100, 200);
      contentPane.add(tax);
      tax.setText("Tax(7.85%) ");
      tax.setHorizontalAlignment(JLabel.RIGHT);

      // Tax JTextField
      taxText = new JTextField();
      taxText.setBounds(115, 225, 80, 22);
      contentPane.add(taxText);

      // total due JLabel
      totalDue = new JLabel();
      totalDue.setBounds(10, 160, 100, 200);
      contentPane.add(totalDue);
      totalDue.setText("Total due: " );
      totalDue.setHorizontalAlignment(JLabel.RIGHT);

      // total due JTextField
      totalDueText = new JTextField();
      totalDueText.setBounds(115, 250, 80, 22);
      contentPane.add(totalDueText);

      // order total JPanel
      JPanel orderTotal = new JPanel();
      GridLayout orderGLay = new GridLayout(3,1);
      orderTotal.setLayout(orderGLay);
      orderTotal.setBounds(10, 170, 200, 125 );

      orderTotal.setBorder(BorderFactory.createTitledBorder(
              BorderFactory.createEtchedBorder(), "Order total" ) );
      contentPane.add( orderTotal );

      // place order JButton
      placeOrder = new JButton();
      placeOrder.setBounds( 252, 175, 100, 24 );
      placeOrder.setText( "Place order" );
      contentPane.add( placeOrder );
      placeOrder.addActionListener(
                new ActionListener() // anonymous inner class
                {
                    // event handler called when calculateJButton is pressed
                    public void actionPerformed(ActionEvent event) {
                        placeOrderActionPerformed(event);
                    }

                } // end anonymous inner class

      ); // end call to addActionListener

      // set up clearOrderJButton
      clearOrder = new JButton();
      clearOrder.setBounds(252,210, 100, 24 );
      clearOrder.setText( "Clear order" );
      contentPane.add( clearOrder );
      clearOrder.addActionListener(
                new ActionListener() // anonymous inner class
                {
                    // event handler called when calculateJButton is pressed
                    public void actionPerformed(ActionEvent event) {
                        clearOrderActionPerformed(event);
                    }

                } // end anonymous inner class

      ); // end call to addActionListener

      // set up exitJButton
      exitButton = new JButton();
      exitButton.setBounds( 425, 260, 70, 24 );
      exitButton.setText( "Exit" );
      contentPane.add( exitButton );

      // set properties of application's window
      setTitle( "Lunch order" ); // set window title
      setResizable(true);      // prevent user from resizing window
      setSize( 525, 350 );        // set window size
      setVisible( true );        // display window
      setLocationRelativeTo(null);
   }
   // calculate subtotal plus tax
   private void placeOrderActionPerformed(ActionEvent event) {

        DecimalFormat dollars = new DecimalFormat("$0.00");

        // declare double variables
        double hamburgerPrice = 6.95;
        double pizzaPrice = 5.95;
        double saladPrice = 4.95;

        double addons = 0;
        double subTotPrice;
        double taxPercent;
        double totalDuePrice;

        if ( hamburgerJButton.isSelected())
        {
            if( lettuceButton.isSelected()){
                addons += 0.25;
            }
            if( mayonnaiseButton.isSelected()){
                addons += 0.25;
            }
            if( mustardButton.isSelected()){
                addons += 0.25;
            }
            else{
                addons -= 0.25;
            }

            subTotPrice = hamburgerPrice + addons;

                taxPercent = subTotPrice * 0.0785;
                totalDuePrice = subTotPrice + taxPercent;

                //display subtotal, tax and total due
                subTotalText.setText( dollars.format( subTotPrice ));
                taxText.setText( dollars.format( taxPercent));
                totalDueText.setText( dollars.format( totalDuePrice ));

        }
        if ( pizzaJButton.isSelected())
        {
            //lettuceButton.setVisible(false);
            //mayonnaiseButton.setVisible(false);
            //mustardButton.setVisible(false);
            croutonsButton.setVisible(false);
            baconBitsButton.setVisible(false);
            breadSticksButton.setVisible(false);
            pepperoniButton.setVisible(true);
            sausageButton.setVisible(true);
            mushroomsButton.setVisible(true);
            //calculation for pizza selection

            if( pepperoniButton.isSelected())
                addons += 0.25;
            if( sausageButton.isSelected())
                addons += 0.25;
            if( mushroomsButton.isSelected())
                addons += 0.25;
            else
                addons -= 0.25;

            subTotPrice = (pizzaPrice + addons);
            taxPercent = subTotPrice * 0.0785;
            totalDuePrice = subTotPrice + taxPercent;

            //display subtotal, tax and total due
            subTotalText.setText( dollars.format( subTotPrice ));
            taxText.setText( dollars.format( taxPercent));
            totalDueText.setText( dollars.format( totalDuePrice ));
        }
        if ( saladJButton.isSelected())
        {
            croutonsButton.setVisible(true);
            baconBitsButton.setVisible(true);
            breadSticksButton.setVisible(true);

            if( croutonsButton.isSelected())
                addons += 0.25;
            if( baconBitsButton.isSelected())
                addons += 0.25;
            if( breadSticksButton.isSelected())
                addons += 0.25;
            else
                addons -= 0.25;

            //calculation for salad selection
            subTotPrice = (saladPrice + addons);
            taxPercent = subTotPrice * 0.0785;
            totalDuePrice = subTotPrice + taxPercent;

            //display subtotal, tax and total due
            subTotalText.setText( dollars.format( subTotPrice ));
            taxText.setText( dollars.format( taxPercent));
            totalDueText.setText( dollars.format( totalDuePrice ));
        }

    } // end method calculateJButtonActionPerformed

    private void clearOrderActionPerformed(ActionEvent event) {

            //reset hamburger and addons to default state
            hamburgerJButton.setSelected(true);
            lettuceButton.setSelected(true);
            mayonnaiseButton.setSelected(false);
            mustardButton.setSelected(true);

            subTotalText.setText("");
            taxText.setText("");
            totalDueText.setText("");


   } // end method calculateJButtonActionPerformed


   public static void main( String args[] )
   {
        LunchOrder application = new LunchOrder();
        application.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
   }

}

Answer 1

您还没有添加任何可以通知任何类型状态更改的监听器，Java 无法神奇地知道您想要它做什么...我希望...

您可以在每个按钮上使用 ItemListener，并根据所选内容对您的 UI 进行更改，例如...

创建一个 ItemListener...

ItemListener il = new ItemListener() {
    @Override
    public void itemStateChanged(ItemEvent e) {
        if (e.getStateChange() == ItemEvent.SELECTED) {
            System.out.println("Hamburger = " + hamburgerJButton.isSelected());
            System.out.println("Pizza = " + pizzaJButton.isSelected());
            System.out.println("Salad = " + saladJButton.isSelected());
        }
    }
};

初始化按钮后，将其注册到每个按钮...

hamburgerJButton.addItemListener(il);
pizzaJButton.addItemListener(il);
saladJButton.addItemListener(il);

看看How to use buttons了解更多详情