Grocery_shop课程
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.text.DecimalFormat;
/**
Grocery shop class
*/
public class Grocery_shop extends JFrame
{
private quantitypanel qty; // A panel for quantity
private Grocery_items items; // A panel for routine charge checkboxes
private JPanel buttonPanel; // A panel for the buttons
private JButton calcButton; // Calculates everything
private JButton exitButton; // Exits the application
/**
Constructor
*/
public Grocery_shop()
{
// Display a title.
setTitle("Victor's Grocery Shop");
// Specify what happens when the close button is clicked.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create a NonRoutinePanel object.
qty = new quantitypanel();
// qty.setBackground(Color.white);
// Create a RoutinePanel object.
items = new Grocery_items( qty );
// Build the panel that contains the buttons.
buildButtonPanel();
// Add the panels to the content pane.
add(items, BorderLayout.WEST);
add(qty, BorderLayout.EAST);
add(buttonPanel, BorderLayout.SOUTH);
// Pack and display the window.
pack();
setVisible(true);
}
/**
The buildButtonPanel method creates a panel containing
buttons.
*/
private void buildButtonPanel()
{
// Create a button to calculate the charges.
calcButton = new JButton("Add Charges");
// Add an action listener to the button.
calcButton.addActionListener(new CalcButtonListener());
// Create a button to exit the application.
exitButton = new JButton("Exit");
// Add an action listener to the button.
exitButton.addActionListener(new ExitButtonListener());
// Put the buttons in their own panel.
buttonPanel = new JPanel();
buttonPanel.add(calcButton);
buttonPanel.add(exitButton);
}
/**
CalcButtonListener is an action listener class for the
calcButton component.
*/
private class CalcButtonListener implements ActionListener
{
/**
actionPerformed method
@param e An ActionEvent object.
*/
public void actionPerformed(ActionEvent e)
{
double totalCharges; // Total charges
// Create a DecimalFormat object to format output.
DecimalFormat dollar = new DecimalFormat("#,##0.00");
// Calculate the total charges
totalCharges = items.getCharges();
//+ nonRoutine.getCharges();
// Display the message.
JOptionPane.showMessageDialog(null, "Total Charges: $" +
dollar.format(totalCharges));
}
} // End of inner class
/**
ExitButtonListener is an action listener class for the
exitButton component.
*/
private class ExitButtonListener implements ActionListener
{
/**
actionPerformed method
@param e An ActionEvent object.
*/
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
} // End of inner class
/**
The main method creates an instance of the JoesAutomotive
class, causing it to display its window.
*/
public static void main(String[] args)
{
Grocery_shop grocery = new Grocery_shop();
}
}
Grocery_item类
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.text.DecimalFormat;
/**
Grocery shop class
*/
public class Grocery_shop extends JFrame
{
private quantitypanel qty; // A panel for quantity
private Grocery_items items; // A panel for routine charge checkboxes
private JPanel buttonPanel; // A panel for the buttons
private JButton calcButton; // Calculates everything
private JButton exitButton; // Exits the application
/**
Constructor
*/
public Grocery_shop()
{
// Display a title.
setTitle("Victor's Grocery Shop");
// Specify what happens when the close button is clicked.
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Create a NonRoutinePanel object.
qty = new quantitypanel();
// qty.setBackground(Color.white);
// Create a RoutinePanel object.
items = new Grocery_items( qty );
// Build the panel that contains the buttons.
buildButtonPanel();
// Add the panels to the content pane.
add(items, BorderLayout.WEST);
add(qty, BorderLayout.EAST);
add(buttonPanel, BorderLayout.SOUTH);
// Pack and display the window.
pack();
setVisible(true);
}
/**
The buildButtonPanel method creates a panel containing
buttons.
*/
private void buildButtonPanel()
{
// Create a button to calculate the charges.
calcButton = new JButton("Add Charges");
// Add an action listener to the button.
calcButton.addActionListener(new CalcButtonListener());
// Create a button to exit the application.
exitButton = new JButton("Exit");
// Add an action listener to the button.
exitButton.addActionListener(new ExitButtonListener());
// Put the buttons in their own panel.
buttonPanel = new JPanel();
buttonPanel.add(calcButton);
buttonPanel.add(exitButton);
}
/**
CalcButtonListener is an action listener class for the
calcButton component.
*/
private class CalcButtonListener implements ActionListener
{
/**
actionPerformed method
@param e An ActionEvent object.
*/
public void actionPerformed(ActionEvent e)
{
double totalCharges; // Total charges
// Create a DecimalFormat object to format output.
DecimalFormat dollar = new DecimalFormat("#,##0.00");
// Calculate the total charges
totalCharges = items.getCharges();
//+ nonRoutine.getCharges();
// Display the message.
JOptionPane.showMessageDialog(null, "Total Charges: $" +
dollar.format(totalCharges));
}
} // End of inner class
/**
ExitButtonListener is an action listener class for the
exitButton component.
*/
private class ExitButtonListener implements ActionListener
{
/**
actionPerformed method
@param e An ActionEvent object.
*/
public void actionPerformed(ActionEvent e)
{
System.exit(0);
}
} // End of inner class
/**
The main method creates an instance of the JoesAutomotive
class, causing it to display its window.
*/
public static void main(String[] args)
{
Grocery_shop grocery = new Grocery_shop();
}
}
quantitypanel class
//import java.awt.LayoutManager;
import java.awt.GridLayout;
//import javax.swing.JCheckBox;
//import javax.swing.JLabel;
import javax.swing.BorderFactory;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class quantitypanel extends JPanel {
private JTextField baked_beans_JT; // JTextField box for baked_beans
private JTextField Cornflakes_JT; // JTextField box for cornflakes
private JTextField Sugar_JT; // JTextField box for sugar box
private JTextField Tea_Bags_JT; // JTextField box for tea bag
private JTextField Instant_Coffee_JT; // JTextField box for Instant_Coffee_Box
private JTextField Bread_JT; // JTextField box for bread box
private JTextField Sausage_JT; // JTextField box for sausage box
private JTextField egg_JT; // JTextField box for egg box
private JTextField milk_JT; // JTextField box for milk
private JTextField potatoes_JT; // JTextField box for potatoes
public quantitypanel()
{
//create JTextField.
baked_beans_JT = new JTextField(5);
Cornflakes_JT = new JTextField(5);
Sugar_JT = new JTextField(5);
Tea_Bags_JT = new JTextField(5);
Instant_Coffee_JT = new JTextField(5);
Bread_JT = new JTextField(5);
Sausage_JT = new JTextField(5);
egg_JT = new JTextField(5);
milk_JT = new JTextField(5);
potatoes_JT = new JTextField(5);
//initialize text field to 0
baked_beans_JT.setText("0");
Cornflakes_JT.setText("0");
Sugar_JT.setText("0");
Tea_Bags_JT.setText("0");
Instant_Coffee_JT.setText("0");
Bread_JT.setText("0");
Sausage_JT.setText("0");
egg_JT.setText("0");
milk_JT.setText("0");
potatoes_JT.setText("0");
public double getBeanqty()
{
return Double.parseDouble(baked_beans_JT.getText());
}
//set Layout manager
setLayout(new GridLayout(10, 1));
//create border and panel title
setBorder(BorderFactory.createTitledBorder("Amount"));
//add text fields to the panel.
add(baked_beans_JT);
add(Cornflakes_JT);
add(Sugar_JT);
add(Tea_Bags_JT);
add(Instant_Coffee_JT);
add(Bread_JT);
add(Sausage_JT);
add(egg_JT);
add(milk_JT);
add(potatoes_JT);
}
}
在上面的代码中，我试图让jtextfield接受一个数字，并选中复选框来计算数字，例如：如果选择了baked_beans复选框，并且用户在数量面板中输入2（baked_beans_JT），程序应该将它们两者相乘以获得电荷......
我做到了，在grocery_items类中，我在此代码中收到错误：
if (baked_beans_box.isSelected())
charges += Baked_Beans * qty.getBeanqty();
说“方法getBeanqty（）未定义类型 quantitypanel“
并且在数量面板类中，我收到此代码的错误：
public double getBeanqty()
{
return Double.parseDouble(baked_beans_JT.getText());
}
错误说明：Syntax error on token "double", @ expected
请帮忙
谢谢：D
答案 0 :(得分：1)
取消注释此声明，因为qty类中使用了Grocery_items：
// private quantitypanel qty; // A panel for quantity
此外，方法getBeanqty嵌入在构造函数quantitypanel中。您不能在方法中使用方法。将其移出构造函数的范围：
public double getBeanqty() {
return Double.parseDouble(baked_beans_JT.getText());
}
Java命名约定显示类名以大写字母开头，通常不使用下划线，这将为您提供QuantityPanel和GroceryItems。