Question

我正在学习Java创建小项目以获得乐趣。我很新，很容易陷入困境，因此我要问的问题。

我正在尝试创建一个简单的购物车程序，在它的主面板中有一个3x3网格，后面包含空标签将被替换为图像。在网格的右侧有四个按钮，添加餐，添加饮料，总价格并清除所有。因此，当单击前两个按钮中的任何一个时，我希望它将当前面板更改为与单击的按钮对应的面板。然后显示的面板具有数据，如组合框中的食物类型，其显示设定的食物和食物的量。然后，当用户选择类型和数量时，按下“添加”按钮，然后更改面板返回主面板，第一个空标签现在有一个已添加到购物车中的项目的图像。

这就是我目前所知道的，据我所知。

主要课程

public class ShoppingCart
{
    public ShoppingCart()
    {
        JFrame app = new JFrame("Cart");

        MainPanel main = new MainPanel();
        app.add(main);

        app.pack();
        app.setResizable(false);
        app.setLocationRelativeTo(null);
        app.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        app.setVisible(true);
    }
    public static void main(String[] args)
    {
        new ShoppingCart();
    }
}

MainPanel类

public class MainPanel extends JPanel implements ActionListener
{
    private final JLabel labels[] = new JLabel[9]; 
    private final JButton button[] = new JButton[4]; 

    public MainPanel()
    {
        String buttonText[] ={"Add a Meal", "Add a Drink", "Total Price", "Clear All"};
        String buttonToolTipText[] =
        {"This will add food", "This will add drink", "This will display the price", "Clear the cart"};

        this.setLayout(new BorderLayout());

        JPanel buttonPanel = new JPanel();
        buttonPanel.setLayout(new GridLayout(4, 1, 2, 2));

        for (int i = 0; i < 4; i++)
        {
            button[i] = new JButton(buttonText[i]);
            button[i].setOpaque(true);
            button[i].setBackground(Color.WHITE);
            button[i].setFont(new Font("Ariel", Font.PLAIN, 18));
            button[i].setPreferredSize(new Dimension(150,50));
            button[i].setVisible(true);
            button[i].setToolTipText(buttonToolTipText[i]);
            button[i].addActionListener(this);
            buttonPanel.add(button[i]);
        }

        JPanel labelPanel = new JPanel(new GridLayout(3, 3, 2, 2));
        Border border = BorderFactory.createLineBorder(Color.GRAY); 
        for (int i = 0; i < 9; i++)
        {
            labels[i] = new JLabel();
            labels[i].setOpaque(true);
            labels[i].setVisible(true);
            labels[i].setPreferredSize(new Dimension(100, 100));
            labels[i].setBorder(border);
            labels[i].setBackground(Color.WHITE);
            labelPanel.add(labels[i]);
            //set empty label to the image of the type chose, 
            //if right clicked, show type and quantity chosen
        }
        add(labelPanel, BorderLayout.WEST);
        add(buttonPanel, BorderLayout.EAST);
    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
        if(button[0] == e.getSource())
        {
            //Change panel to Meal panel
        }
        if(button[1] == e.getSource())
        {
            //Change panel to Drink panel
        }
        if(button[2] == e.getSource())
        {
            //JOptionPane to show total price
        }
        if(button[3] == e.getSource())
        {
            //Check whether labels are empty, if not clear them else display message
        }
    }
}

MealPanel类

public class MealPanel extends JPanel implements ActionListener
{
    public MealPanel()
    {
        this.setLayout(new BorderLayout());

        JPanel titlePanel = new JPanel();
        JPanel labelPanel = new JPanel(new GridLayout(2, 1, 3, 3));
        JPanel inputField = new JPanel(new GridLayout(2, 1, 3, 3));
        JPanel addCancel = new JPanel();

        JLabel title = new JLabel("Add a Meal");
        title.setBorder(BorderFactory.createMatteBorder(5,0,10,0, new Color(0,0,0,0)));
        titlePanel.add(title);

        JLabel type = new JLabel("Type:", JLabel.RIGHT);
        labelPanel.add(type);
        JLabel quantity = new JLabel("Quantity:", JLabel.RIGHT);
        labelPanel.add(quantity);

        final String arr[] = {"Burger", "Pizza"};
        JComboBox mealType = new JComboBox(arr);
        inputField.add(mealType);
        JTextField quant = new JTextField();
        inputField.add(quant);

        JButton add = new JButton("Add");
        add.addActionListener(this);
        addCancel.add(add);
        JButton cancel = new JButton("Cancel");
        cancel.addActionListener(this);
        addCancel.add(cancel);

        add(titlePanel, BorderLayout.NORTH);
        add(labelPanel, BorderLayout.WEST);
        add(inputField, BorderLayout.EAST);
        add(addCancel, BorderLayout.SOUTH);
    }

    @Override
    public void actionPerformed(ActionEvent e)
    {
       //If cancel is pressed, return back to main, nothing changed on this panel
       //else if add is pressed, set the type and quantity and return back to main
    }
}

我想显示的是，我不知道如何将当前面板专门更改为通过单击按钮选择的面板。然后，当显示面板时，如何设置数据然后将面板更改回MainPanel，然后将标签中显示的那种食物显示为网格中与所选类型对应的图像，因此要么是汉堡还是第一个空标签中的披萨。

如何进行申请？

在面板之间交换

0 个答案: