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我對Java更新，所以我仍然試圖瞭解如何正確更新變量。我正在創建一個充當餐館菜單的程序。所列出的菜單項目將出現在左側，並且一旦用戶檢查了一個項目並且點擊了右側按鈕，該項目將出現在右側，並且該項目的價格應該被添加到總變量中;但是，這是行不通的。有一些不必要的代碼，但如果可以的話，請忽略這些和一些評論。謝謝。總變量不會更新
package finalproject;
import java.awt.event.*;
import java.awt.*;
import javax.swing.*;
public class MenuFrame extends JFrame implements ActionListener {
final double BURGER_PRICE = 6.24;
final double FISH_PRICE = 13.78;
final double SOUP_PRICE = 4.49;
final double CHICKEN_PRICE = 11.36;
final double SALAD_PRICE = 5.60;
final double FRIES_PRICE = 3.24;
JPanel menuPanel = new JPanel(); //Panel to place the menu in, which will be on left side
JPanel buttonPanel = new JPanel(); //Panel to place buttons in, which will be in center
JPanel orderPanel = new JPanel(); //Panel to place order menu in, which will be on right side
JLabel menuLabel = new JLabel("Menu"); //Label for the menu
JLabel orderLabel = new JLabel("Your Order"); //Label for the user's order
JCheckBox burger = new JCheckBox("Burger: $6.24", false); //Burger check box
JCheckBox fish = new JCheckBox("Fish: $13.78", false); //Fish check box
JCheckBox soup = new JCheckBox("Soup: $4.49", false); //Soup check box
JCheckBox chicken = new JCheckBox("Chicken: $11.36", false); //Chicken check box
JCheckBox salad = new JCheckBox("Salad: $5.60", false); //Salad check box
JCheckBox fries = new JCheckBox("Fries: $3.24", false); //Fries check box
JButton rightButton = new JButton("->"); //Button to move items from left to right
JButton leftButton = new JButton("<-"); //Button to move items from right to left
JLabel skipPosition = new JLabel(""); //Label used to skip position in GridLayout
static double totalPrice = 0; //Total price of order
Font titleFont = new Font("Times New Roman",Font.BOLD,20);
JLabel totalLabel = new JLabel(""); //total label
public MenuFrame() {
setLayout(new GridLayout(0,3));
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setSize(1055, 275); //Set size of Menu Frame
menuPanel.setLayout(new GridLayout(0,3)); //Setting Menu's layout to GridLayout
//Box buttonBox = Box.createVerticalBox(); //Creating box object for button panel
buttonPanel.setLayout(new GridLayout(8,3));
orderPanel.setLayout(new GridLayout(0,3)); //Setting Order's layout to FlowLayout
menuLabel.setFont(titleFont);
orderLabel.setFont(titleFont);
//Adding menu items to Menu
menuPanel.add(new JLabel(""));
menuPanel.add(menuLabel);
menuPanel.add(new JLabel(""));
menuPanel.add(burger);
menuPanel.add(fish);
menuPanel.add(soup);
menuPanel.add(chicken);
menuPanel.add(salad);
menuPanel.add(fries);
//Adding buttons to Box
//buttonBox.add(rightButton);
//buttonBox.add(Box.createVerticalStrut(100));
//buttonBox.add(leftButton);
//Adding box to button panel
//buttonPanel.add(buttonBox);
//Adding "Your Order" label to Order. Items will be subsequently added or removed
orderPanel.add(new JLabel(""));
orderPanel.add(orderLabel);
orderPanel.add(new JLabel(""));
totalLabel.setText("$" + totalPrice);
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(rightButton);
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(leftButton);
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(new JLabel(""));
buttonPanel.add(totalLabel);
//Adding action listener to rightButton and leftButton
rightButton.addActionListener(this);
leftButton.addActionListener(this);
add(menuPanel);
add(buttonPanel);
add(orderPanel);
}
@Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
//If right button was clicked
if(source == rightButton) {
//if burger was selected and is in the menu panel
if(burger.isSelected() && burger.getParent() == menuPanel) {
//Move burger from menu to order, deselect burger, and add 6.24 to total price
menuPanel.remove(burger);
orderPanel.add(burger);
burger.setSelected(false);
totalPrice += BURGER_PRICE;
}
//if fish was selected and is in the menu panel
if(fish.isSelected() && fish.getParent() == menuPanel) {
//Move fish from menu to order, deselect fish, and add 13.78 to total price
menuPanel.remove(fish);
orderPanel.add(fish);
fish.setSelected(false);
totalPrice += FISH_PRICE;
}
//if soup was selected and is in the menu panel
if(soup.isSelected() && soup.getParent() == menuPanel) {
//Move soup from menu to order, deselect soup, and add 4.49 to total price
menuPanel.remove(soup);
orderPanel.add(soup);
soup.setSelected(false);
totalPrice += SOUP_PRICE;
}
//if chicken was selected and is in the menu panel
if(chicken.isSelected() && chicken.getParent() == menuPanel) {
//Move chicken from menu to order, deselect chicken, and add 11.36 to total price
menuPanel.remove(chicken);
orderPanel.add(chicken);
chicken.setSelected(false);
totalPrice += CHICKEN_PRICE;
}
//if salad was selected and is in the menu panel
if(salad.isSelected() && salad.getParent() == menuPanel) {
//Move salad from menu to order, deselect salad, and add 5.60 to total price
menuPanel.remove(salad);
orderPanel.add(salad);
salad.setSelected(false);
totalPrice += SALAD_PRICE;
}
//if fries was selected and is in the menu panel
if(fries.isSelected() && fries.getParent() == menuPanel) {
//Move fries from menu to order, deselect fries, and add 3.24 to total price
menuPanel.remove(fries);
orderPanel.add(fries);
fries.setSelected(false);
totalPrice += FRIES_PRICE;
}
}
//if left button was clicked
if(source == leftButton) {
//if burger was selected and is in the order panel
if(burger.isSelected() && burger.getParent() == orderPanel) {
//Move burger from order to menu, deselect burger, and remove 6.24 from total price
orderPanel.remove(burger);
menuPanel.add(burger);
burger.setSelected(false);
totalPrice -= BURGER_PRICE;
}
//if fish was selected and is in the order panel
if(fish.isSelected() && fish.getParent() == orderPanel) {
//Move fish from order to menu, deselect fish, and remove 13.78 from total price
orderPanel.remove(fish);
menuPanel.add(fish);
fish.setSelected(false);
totalPrice -= FISH_PRICE;
}
//if soup was selected and is in the order panel
if(soup.isSelected() && soup.getParent() == orderPanel) {
//Move soup from order to menu, deselect soup, and remove 4.49 from total price
orderPanel.remove(soup);
menuPanel.add(soup);
soup.setSelected(false);
totalPrice -= SOUP_PRICE;
}
//if chicken was selected and is in the order panel
if(chicken.isSelected() && chicken.getParent() == orderPanel) {
//Move chicken from order to menu, deselect chicken, and remove 11.35 from total price
orderPanel.remove(chicken);
menuPanel.add(chicken);
chicken.setSelected(false);
totalPrice -= CHICKEN_PRICE;
}
//if salad was selected and is in the order panel
if(salad.isSelected() && salad.getParent() == orderPanel) {
//Move salad from order to menu, deselect salad, and remove 5.60 from total price
orderPanel.remove(salad);
menuPanel.add(salad);
salad.setSelected(false);
totalPrice -= SALAD_PRICE;
}
//if fries was selected and is in the order panel
if(fries.isSelected() && fries.getParent() == orderPanel) {
//Move fries from order to menu, deselect fries, and remove 3.24 from total price
orderPanel.remove(fries);
menuPanel.add(fries);
fries.setSelected(false);
totalPrice -= FRIES_PRICE;
}
}
//Make changes appear
repaint();
revalidate();
}
public static void main(String[] args) {
//Instantiating MenuFrame object
MenuFrame menuFrame = new MenuFrame();
//Making frame visible
menuFrame.setVisible(true);
}
告訴我們什麼實際上不工作？不打印？變量不能設置？請詳細說明 –
1.如果您不熟悉Java，則可能不應該嘗試編寫GUI。 2.您確實需要限制代碼量，因此只包含相關的代碼。 – Carcigenicate
這裏有太多的代碼，它涉及異步的東西和聽衆，以及真正增加複雜性的東西。請首先在一些關鍵位置放置'System.out.println'，以確保您獲得了應該添加到總量中的代碼。所以如果你認爲應該選擇一個漢堡，那麼在應該添加的'if'裏面放一個'println'。如果你沒有到達那裏，那麼嘗試其他的'System.out.printlns'來查看'source == rightbutton'是否爲true，如果'actionPerformed'被調用，等等。 – ajb