Question

我正在为大学做书店GUI，

我有4个课程：Book，bookfile，BookGUI，TestClass。

我在测试中创建了一个bookFile()对象（bkf），并向其添加了Book（b），然后创建了我的BookGUI （bkf）对象（g）将bkf传递给它。

我只能编辑BookGUI类！

在bkf

中创建我的BookGUI对象时，我无法弄清楚如何访问我传入的actionPerformed()对象

我需要在按下添加按钮时更新Arraylist中的bookFile()，如何在预先执行的操作中调用.addBook()对象上的bkf？

请仅回答我提出的问题，因为除非是良好的编码道德规范，否则我将自己解决问题。

感谢您的帮助。

识别TestClass

public class TestClass {

 public static void main(String[] args)
    {
        bookFile bkf = new bookFile();   
        Book b = new Book("Dan Brown","The daVinci Code",3,10.99);
        bkf.addBook(b);
        BookGUI g = new BookGUI(bkf);   
        g.setVisible(true);
    }
}

BookGUI

import javax.swing.*;
import javax.swing.border.TitledBorder;

import java.awt.*;
import java.awt.event.*;


class BookGUI extends JFrame implements ActionListener{

 private final int width = 290;
 private final int height = 260;
 private JLabel title, author, quantity, price; 
 private JTextField titleTBox, authorTBox, quantityTBox, priceTBox;
 private JTextArea  outputBox;
 private JButton addButton, totalQ, totalV, exit;
 private TitledBorder border;

 private Container c;

 private JPanel input = new JPanel(new GridLayout(0,2));
 private JPanel buttons = new JPanel(new GridLayout(2,2));
 private JPanel output = new JPanel(new FlowLayout());



 public BookGUI(bookFile bkf)
 {



     c = getContentPane();
     this.setLayout(new BorderLayout(2,2));
     this.setSize(width, height);

     this.add(input,BorderLayout.NORTH);
     input.setBackground(Color.LIGHT_GRAY);
     title = new JLabel("Title");
     input.add(title);


     titleTBox = new JTextField();
     input.add(titleTBox);

     author = new JLabel("Author");
     input.add(author);

     authorTBox = new JTextField();
     input.add(authorTBox);

     quantity = new JLabel("Quantity");
     input.add(quantity);

     quantityTBox = new JTextField();
     input.add(quantityTBox);

     price = new JLabel("Price");
     input.add(price);

     priceTBox = new JTextField();
     input.add(priceTBox);

     this.add(buttons,BorderLayout.CENTER);
     addButton = new JButton("Add");
     buttons.add(addButton);
     addButton.addActionListener(this);

     totalQ = new JButton("Total Quantity");
     buttons.add(totalQ);
     totalQ.addActionListener(this);

     totalV = new JButton("Total Value");
     buttons.add(totalV);
     totalV.addActionListener(this);

     exit = new JButton("Exit");
     buttons.add(exit);
     exit.addActionListener(this);

     this.add(output,BorderLayout.SOUTH);
     output.setBorder(new TitledBorder("Output"));
     outputBox = new JTextArea(3, 20);
     output.add(outputBox);




 }


public void actionPerformed(ActionEvent e) {

    if(e.getSource() == addButton)
    {


         int q = Integer.parseInt(quantityTBox.getText());
         double p = Double.parseDouble(priceTBox.getText());
         Book nb = new Book(titleTBox.getText(), authorTBox.getText(), q,     p);
         .addBook(nb);


        outputBox.setText(bkf.getDetails());
    }


}

}

bookFile

import java.util.ArrayList;

public class bookFile {

private ArrayList <Book> blist = new ArrayList<Book>();

public void addBook(Book b)
{
    blist.add(b);
}

public Book getBook(int i) {
    return blist.get(i);
}

// returns a string containing all the book details in the array list
public String getDetails()
{   
    String output="";
    for (int i=0;i<blist.size();i++)
    {
        output += (i+1)+"."+blist.get(i).getTitle() +","+ blist.get(i).getAuthor()+","
                + blist.get(i).getQuantity()+","+ blist.get(i).getPrice() +"\n";            
    }
    return output;
}

// returns the total quantity of books in the array list
public int gettotalQuantity()
{
    int total=0;
    for (int i=0;i<blist.size();i++)
    {
        total += blist.get(i).getQuantity();    
    }

    return total;
}

// returns the total value of books in the array list
public double gettotalValue()
{
    double total=0;
    for (int i=0;i<blist.size();i++)
    {
        total += (blist.get(i).getQuantity()*blist.get(i).getPrice());  
    }

    return total;
}

}

图书

public class Book {

//Member Variables:
private String author;
private String title;
private int quantity;
private double price;

public Book(String a, String t, int q, double p)
{
    author=a;
    title=t;
    quantity=q;
    price=p;
}
//Getters & Setters:
public String getAuthor()
{
    return author;
}
public void setAuthor(String a)
{
    author=a;
}
public String getTitle()
{
    return title;
}
public void setTitle(String t)
{
    title=t;
}
public double getPrice()
{
    return price;
}
public void setPrice(double p)
{
    price = p;
}
public int getQuantity()
{
    return quantity;
}
public void setQuantity(int q)
{
    quantity = q;
}

}

Answer 1

 private final bookFile bkf;

 public BookGUI(bookFile bkf)
 {
     this.bkf = bkf;

     //The rest of your constructor.. 

 }

在旁注中，bookFile应为BookFile，因为它是一个类。

Answer 2

在BookGUI的构造函数中保存对BookFile实例的引用。然后，您可以从BookGUI中的任何方法访问它。此外，您应该避免使用bkg之类的短变量名称。使您的代码更难理解。

<强> BookGUI.java

// ...
private final BookFile bookFile;

public BookGUI(BookFile bookFile)
{
    this.bookFile = bookFile;
    // ...

修改

正如@Majid L所说，类型名称应该以大写字母开头，因此bookFile应为BookFile

从actionPerformed中访问对象

2 个答案: