向容器添加窗口

Question

我一直收到这个错误

    import javax.swing.*; 
    import java.awt.*;
    import java.awt.event.*;
    import java.util.*;
    import javax.swing.table.*;
    import java.awt.Container.*;
     public class main extends JFrame implements ActionListener
    {

    JButton CustomerOrder;
    JButton SoftwareProducts;
    JButton BooksProducts;
    JButton AddBooks;
    JButton StaffMember;
    JButton LoginView;

    static ArrayList<Software> softwareList = new ArrayList<Software>();
    CardLayout c1 = new CardLayout();

    JPanel mainPanel;
    SoftwareProducts addsoftware;
    CustomerOrder customerorder;
    BooksProducts addProduct;
    AddBooks addBook;
    SoftwareProducts sf = new SoftwareProducts();
    //Press submit;
    public static void main(String[] args)
   {
    new main();
    JFrame frame = new JFrame("Selling Product");
    frame.setLocationRelativeTo(null);
    //frame.getContentPane().add(main, BorderLayout.CENTER);
    //new CustomerOrder();
    //EmailFrame email=new EmailFrame();
    //CustomerOrder co = new CustomerOrder();
    //LoginView login = new LoginView();
  }
public main(){
    super();


  // getContentPane().setBackground(Color.green);


   setSize(700,800);
   setLayout(new FlowLayout());
     /*CardLayout cardLayout = (CardLayout) mainPanel.getLayout();
     cardLayout.show(mainPanel, "softwareProducts");
     */

   //CustomerOrder co = new CustomerOrder();
   //add(co);

   SoftwareProducts = new JButton("SoftwareProducts");
   SoftwareProducts.setSize(150,40);
   SoftwareProducts.setLocation(20,50);

   CustomerOrder = new JButton("CustomerOrder");
   CustomerOrder.setSize(160,40);
   CustomerOrder.setLocation(150,50);

   BooksProducts = new JButton("BooksProducts");
   BooksProducts.setSize(200,40);
   BooksProducts.setLocation(310,50);

   AddBooks = new JButton("AddBook");
   AddBooks.setSize(200,40);
   AddBooks.setLocation(310,50);

   StaffMember = new JButton("StaffMember");
   StaffMember.setSize(200,40);
   StaffMember.setLocation(310,50);

   LoginView = new JButton("LoginView");
   LoginView.setSize(150,40);
   LoginView.setLocation(20,50);

   SoftwareProducts.addActionListener(this);
   add(SoftwareProducts);
   CustomerOrder.addActionListener(this);
   add(CustomerOrder);
   BooksProducts.addActionListener(this);
   add(BooksProducts);
   AddBooks.addActionListener(this);
   add(AddBooks);

   StaffMember.addActionListener(this);
   add(StaffMember);


   mainPanel = new JPanel();
   mainPanel.setBackground(Color.BLUE);
   mainPanel.setPreferredSize(new Dimension(600,500));
   mainPanel.setLayout(c1);



   addsoftware = new SoftwareProducts();
   mainPanel.add(addsoftware,"addsoftware");

   customerorder = new CustomerOrder();  ////// I am getting the error
        from this part of code  
   mainPanel.add(customerorder,"customerorder");///// I am getting the     
         error from this part of code  
   addProduct = new BooksProducts();
   mainPanel.add(addProduct,"addProduct");

   addBook = new AddBooks();
   mainPanel.add(addBook,"addBook");

  /*  mainPanel.add(SoftwareProducts);
     mainPanel = new JPanel(new CardLayout());
     mainPanel.add(SoftwareProducts);
     getContentPane().add(mainPanel);

     addProduct = new BooksProducts();
     mainPanel.add(addProduct,"addProduct");

    */


      add(mainPanel);



       setVisible(true);
}


public void actionPerformed(ActionEvent e)
{
   if(e.getSource() == SoftwareProducts)
   {
    c1.show(mainPanel,"addsoftware");
    this.setTitle("SoftwareProducts");
    //System.out.println("Softwares");
    }

    if(e.getSource() == CustomerOrder)
   {
    c1.show(mainPanel,"customerorder");
    this.setTitle("CustomerOrder");
    //System.out.println("Custmers");
    }

     if(e.getSource() == BooksProducts)
   {
     c1.show(mainPanel,"addProduct");
     this.setTitle("BooksProducts");
    }
    if(e.getSource() == AddBooks)
   {
     c1.show(mainPanel,"addBook");
     this.setTitle("AddBooks");
    }
   if(e.getSource() == LoginView)
   {
     c1.show(mainPanel,"LogIN");
     this.setTitle("LOGIN");
    }
}
      /*  public void actionPerformed(ActionEvent e)
        {
      if(e.getSource() == press)
 {
    System.out.println("addProducts");
    }
   }*/
  }

和我的customerOrder类

      import javax.swing.*;
      import javax.swing.table.*; 
      import java.awt.*;
      import java.awt.event.*;
      import java.util.Arrays; 
      import java.util.ArrayList;
      import java.util.Collections;
      import java.util.List;
      import java.util.*;
      import java.io.*;
       public class CustomerOrder extends JFrame 
     implements  ActionListener 
  {
//JButton asd = new JButton("BUTTON");
//JTextField productID;
//JTextField productName;
//JTextField productCost;
//JTextField productPYear;
//JTextField productPHouse;
JButton showOrder;

DefaultListModel<String> model = new DefaultListModel<>();
JList <String>orderList = new JList(model);
JTable softwareTabel = new JTable();

//DefaultTableModel tableModel = new DefaultTableModel(0, 1);

public CustomerOrder()
{
    //super();
   // JLabel toLabel=new JLabel("Product ID: ");
    //JTextField to=new JTextField();

    setLayout(new FlowLayout());

   /* 
    productName = new JTextField(12);
    add(productName);
    productCost = new JTextField(12);
    add(productCost);
    productPYear = new JTextField(12);
    add(productPYear);

    productPHouse = new JTextField(12);
    add(productPHouse);
    */
    showOrder = new JButton("SHOW ORDER");
    showOrder.setSize(25,40);
    showOrder.addActionListener(this);
    add(showOrder); 


}

public void actionPerformed(ActionEvent e)
{
    //Object[] colNames={"Product ID","Processor","RAm"};
    if(e.getSource() == showOrder)
    {  
         model.removeAllElements();
       /*  GridLayout exLayout = new GridLayout(3, 3);
         JLabel ram,processor; 
         ram = new JLabel("RAM");
         processor = new JLabel("Processor");
         String softwaredata[] = {"ID","RAM","Processor","Product ID","Product Name","Product Year","Product Year","Product PublishHouse"};
         JPanel panel = new JPanel();
         panel.setLayout(new GridLayout(8,   3));
         add(ram);
         add(processor);
         JTable table = new JTable();*/
         //DeafultTableModel dm = new DeafultTableModel(0,0);
          //String header[] = new String[] {"RAM", "Processor","ProductID","Product Name","Product Year","Product Publish House"}; 
          //dm.setColumnIdentifiers(header);
          //Object[][] software = new Object[8][3];
          //model.addRow(orderList.toArray());

          int x = 0;
       while (x < main.softwareList.size())
        {
            //./model.addElement(main.softwareList.get(x).getproductYear());
             model.addElement(""+main.softwareList.get(x).getproductID());
             model.addElement(""+main.softwareList.get(x).getRam());
             model.addElement(""+ main.softwareList.get(x).getProcessor());
             model.addElement(""+ main.softwareList.get(x).getproductID()); 
             model.addElement(main.softwareList.get(x).getproductName());
             model.addElement(""+ main.softwareList.get(x).getproductYear());
             model.addElement(main.softwareList.get(x).getproductPublishHouse());
             //model.addElement(main.softwareList.get(x).getproductID());*/              
             x++;
          //System.out.println("as");

        }
          /* ArrayList<String> table1 = new ArrayList();
          ArrayList<ArrayList<String>> table2 = new ArrayList();
          table1.add("Product ID");
          table1.add("RAM");
          table1.add("Processor");
          table1.add("Product Name");
          table1.add("Product Year");
          table1.add("Product PHouse");
          Object[] software = table1.toArray();
          String[] [] softwarest = new String[table1.size()][];
          int i = 0;
          for (List<String> next : table2){
             softwarest[i++] = next.toArray(new String[next.size()]);
            }

            JTable newTable = new JTable(softwarest,software);
            JFrame frame = new JFrame();
            frame.getContentPane().add(new JScrollPane(newTable));
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            */
             //table.add(model);
         // add(orderList);
        //Object[] column = {"RAM:", "Processor:"};
        //Object[][] data = {{"RAM:", "Processor:"}};
        //JTable table = new JTable();
        //table.setShowGrid(false);
        //table.setTableHeader(null); 
    }

}

 }

当我运行这段代码时，我从customerorder = new customerorder的主类中得到以下异常;mainPanel.add (customerorder customerorder)

Answer 1

customorder是CustomerOrder的实例，由JFrame扩展而来;public class CustomerOrder extends JFrame

如错误状态illegalargumentexception adding a window to a container;将一个窗口添加到另一个窗口是非法的，这根本没有意义。

这是我们不鼓励从像JFrame这样的顶级容器直接扩展的原因之一。

让CustomerOrder像任何正常框架一样可见(尽管这可能会导致其他问题)，或者更好的是，将CustomerOrder组件作为JPanel的基础

public class CustomerOrder extends JPanel {
    //...
}

这样你就可以把它添加到任何你需要的容器中。

Answer 2

我不知道这个逻辑是否正确，但只是玩玩，试图找出原因，它不适合我自己，我得出的结论是:

• 扩展JFrame导致只创建一个对象，为什么它试图将JFrame frame;对象添加到自己，从而导致异常…

• 扩展JPanel允许JFrame帧;<——要划分为容器的对象&一个组件，它允许你frame.add(this) . .

frame.add(this)是由JPanel方法.add()调用的组件

如果这是错误的，请纠正…