Java sale 从 main 方法运行，而不是作为 java beans

Question

如果我想在主方法或作为应用程序而不是作为 java beans 运行销售，我应该在主方法中添加什么？？？，因为现在作为 java beans 运行它工作正常，但是当我作为应用程序运行它时，什么也没有发生，因为我需要在 main 方法中添加一些代码。

import java.awt.Frame;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.awt.Dimension;
import java.awt.Label;
import java.awt.Rectangle;
import java.awt.Point;
import java.awt.Button;

import java.awt.TextField;

public class Sale extends Frame implements ActionListener, WindowListener {

    private static final long serialVersionUID = 1L;
    private Label custNameLbl = null;
    private Label itemNameLbl = null;
    private Label qtyLbl = null;
    private Label priceLbl = null;
    private Label msgLbl = null;
    private Button button = null;
    private TextField custNameTF = null;
    private TextField itemNameTF = null;
    private TextField qtyTF = null;
    private TextField priceTF = null;

    @Override
    public void windowOpened(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void windowClosing(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void windowClosed(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void windowIconified(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void windowDeiconified(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void windowActivated(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void windowDeactivated(WindowEvent e) {
        // TODO Auto-generated method stub

    }

    @Override
    public void actionPerformed(ActionEvent e) {
        int qty;
        double price;
        double cost;
        qty = Integer.parseInt(qtyTF.getText());
        price = Double.parseDouble(priceTF.getText());
        cost = price * qty * 1.065;
        this.add(msgLbl, null);
        msgLbl.setText("The cost of this " + "transaction is: $" + cost);
        custNameTF.setText("");
        itemNameTF.setText("");
        qtyTF.setText("");
        priceTF.setText("");

        // System.out.println(cost);

        // TODO Auto-generated method stub

    }

    /**
     * This method initializes button
     * 
     * @return java.awt.Button
     */
    private Button getButton() {
        if (button == null) {
            button = new Button();
            button.setLocation(new Point(126, 198));
            button.setLabel("Calc");
            button.setSize(new Dimension(40, 23));
            button.addActionListener(this);
        }
        return button;
    }

    /**
     * This method initializes custNameTF
     * 
     * @return java.awt.TextField
     */
    private TextField getCustNameTF() {
        if (custNameTF == null) {
            custNameTF = new TextField();
            custNameTF.setBounds(new Rectangle(116, 42, 140, 23));
        }
        return custNameTF;
    }

    /**
     * This method initializes itemNameTF
     * 
     * @return java.awt.TextField
     */
    private TextField getItemNameTF() {
        if (itemNameTF == null) {
            itemNameTF = new TextField();
            itemNameTF.setBounds(new Rectangle(116, 77, 137, 23));
        }
        return itemNameTF;
    }

    /**
     * This method initializes qtyTF
     * 
     * @return java.awt.TextField
     */
    private TextField getQtyTF() {
        if (qtyTF == null) {
            qtyTF = new TextField();
            qtyTF.setBounds(new Rectangle(95, 114, 56, 23));
        }
        return qtyTF;
    }

    /**
     * This method initializes priceTF
     * 
     * @return java.awt.TextField
     */
    private TextField getPriceTF() {
        if (priceTF == null) {
            priceTF = new TextField();
            priceTF.setBounds(new Rectangle(203, 114, 49, 23));
        }
        return priceTF;
    }

    /**
     * I need to run sale from main method or in other words pass the values to
     * msgLbl
     */
    public static void main(String[] args) {
        Sale saleTest = new Sale();

        // TODO Auto-generated method stub

    }

    /**
     * This is the default constructor
     */
    public Sale() {
        super();
        initialize();
    }

    /**
     * This method initializes this
     * 
     * @return void
     */
    private void initialize() {
        msgLbl = new Label();
        msgLbl.setText("Label");
        msgLbl.setSize(new Dimension(290, 23));
        msgLbl.setAlignment(Label.CENTER);
        msgLbl.setLocation(new Point(4, 170));
        priceLbl = new Label();
        priceLbl.setBounds(new Rectangle(161, 114, 36, 23));
        priceLbl.setAlignment(Label.RIGHT);
        priceLbl.setText("Price");
        qtyLbl = new Label();
        qtyLbl.setBounds(new Rectangle(35, 114, 51, 23));
        qtyLbl.setAlignment(Label.RIGHT);
        qtyLbl.setText("Quantity");
        itemNameLbl = new Label();
        itemNameLbl.setBounds(new Rectangle(34, 77, 72, 23));
        itemNameLbl.setAlignment(Label.RIGHT);
        itemNameLbl.setText("Item Name");
        custNameLbl = new Label();
        custNameLbl.setBounds(new Rectangle(5, 42, 101, 23));
        custNameLbl.setAlignment(Label.RIGHT);
        custNameLbl.setText("Customer Name");
        this.setLayout(null);
        this.setSize(300, 229);
        this.setTitle("Frame");

        this.add(custNameLbl, null);
        this.add(itemNameLbl, null);
        this.add(qtyLbl, null);
        this.add(priceLbl, null);

        this.add(getButton(), null);
        this.add(getCustNameTF(), null);
        this.add(getItemNameTF(), null);
        this.add(getQtyTF(), null);
        this.add(getPriceTF(), null);
    }
}

Answer 1

您需要一个 Sale 构造函数来添加所有组件。类似这样的东西，尽管您可能想使用 LayoutManagers 修复格式。

public Sale {
    add(custNameLbl);
    add(itemNameLbl);
    add(qtyLbl);
    ...
    // add the rest of your components
}

以下是运行它的方法。

public class Sale extends Frame implements ActionListener, WindowListener {

    public Sale {
       add(custNameLbl);
       add(itemNameLbl);
       add(qtyLbl);
       ...
       // add the rest of your components
    }

    ...
    // rest of code
    ...

    public static void main(String[] args){
        SwingUtilities.invokeLater(new Runnable(){
            public void run(){
                Sale sale = new Sale();
                sale.setVisible(true);
            }
        });
    }
}

实际上，在代码按照您想要的方式运行之前，您还需要修复一些其他问题。但要使其启动并运行，请记住您需要在 main 中实例化 Frame 之前添加组件。

另一个提示:您似乎让 Frame 实现了 ActionListener，但我认为您真正想要的是使用您的按钮而不是框架注册 `ActionListener。考虑以下因素

button.addActionListener(new ActionListener(){
    @Override
    public void actionPerformed(ActionEvent e) {
        int qty;
        double price;
        double cost;
        qty = Integer.parseInt(qtyTF.getText());
        price = Double.parseDouble(priceTF.getText());
        cost = price * qty * 1.065;
        this.add(msgLbl, null);
        msgLbl.setText("The cost of this " + "transaction is: $" + cost);
        custNameTF.setText("");
        itemNameTF.setText("");
        qtyTF.setText("");
        priceTF.setText("");

        // System.out.println(cost);

        // TODO Auto-generated method stub

    }
});