java - 如何在主程序之外使用 JButton 来 "hide"JFrame

Question

所以我几乎完成了这个项目，最后一件事是“隐藏”按钮。我的老师从未指导过该怎么做，但由于这让我很恼火，而且我找不到有效的答案，所以我想我应该向你们好心的人请教。

我已经尝试过:

1. setExtendedState(JFrame.ICONIFIED)//导致编译器错误，找不到我的变量名
2. setState(JFrame.ICONIFIED)//同样的问题，“找不到符号”，或者更确切地说找到我的变量
3. setVisible(false)//这不起作用，因为它隐藏了我的整个框架，并且在不关闭程序的情况下我无法取回它。

我使用Container c = getContentPane()来创建 Pane ，然后在我使用的主窗口中:

ClassName variableName = new ClassName() to create the parameters.

这就是我的教学方式，我现在必须使用这种方式(因为这是我的老师想要的)，但我注意到还有其他方法可以实现相同的目标。

任何特定于我的程序的输入都会很棒!谢谢!

我的程序如下(我发布了整个内容，因此不会遗漏任何内容):

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.Arrays;

public class Project9 extends JFrame
{
  Font f1 = new Font("Serif", Font.BOLD, 30);
  Font f2 = new Font("Serif", Font.PLAIN, 18);

  private BOOKItem[] bookArray = new BOOKItem[10];

  private JLabel headerLbl;
  private JLabel messagesLbl;

  private JTextField idLabelFld;
  private JTextField idFld;
  private JTextField priceLabelFld;
  private JTextField priceFld;
  private JTextField numInStockLabelFld;
  private JTextField numInStockFld;
  private JTextField codeLabelFld;
  private JTextField codeFld;
  private JTextField messagesFld;

  private JButton insertBtn;
  private JButton deleteBtn;
  private JButton displayBtn;
  private JButton displayOneBtn;
  private JButton hideBtn;
  private JButton clearBtn;

  private String input = "";
  private String displayOneStr = "";

  private int idInput = 0;
  private double priceInput = 0.0;
  private int numInStockInput = 0;
  private int codeInput = 0;

  private int index = 0;
  private int numItems = 0;
  private int responseCode = 0;

  private Container c = getContentPane();

  //Main Method, sets arrayFrame params
  public static void main(String[] args)
  {
        Project9 arrayFrame = new Project9();
        arrayFrame.setSize(555,450);
        arrayFrame.setVisible(true);
        arrayFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  }     


  //Constructor
  public Project9()
  {
        //Creates the array 
        for (int i = 0; i < bookArray.length; i++)
        {
              bookArray[i] = new BOOKItem();
              System.out.println(bookArray[i]);
        } 

        setTitle("Project 9");
        c.setLayout(new FlowLayout());

        headerLbl = new JLabel("Data Entry: BestBargainBook Store");
        headerLbl.setFont(f1);
        c.add(headerLbl);

        idLabelFld = new JTextField("Enter ID:", 15);
        idLabelFld.setEditable(false);
        c.add(idLabelFld);

        idFld = new JTextField(25);
        c.add(idFld);

        priceLabelFld = new JTextField("Enter Price:", 15);
        priceLabelFld.setEditable(false);
        c.add(priceLabelFld);

        priceFld = new JTextField(25);
        c.add(priceFld);

        numInStockLabelFld = new JTextField("Enter Number In Stock:", 15);
        numInStockLabelFld.setEditable(false);
        c.add(numInStockLabelFld);

        numInStockFld = new JTextField(25);
        c.add(numInStockFld);

        codeLabelFld = new JTextField("Enter Code: 1,2,3 or 4:", 15);
        codeLabelFld.setEditable(false);
        c.add(codeLabelFld);

        codeFld = new JTextField(25);
        c.add(codeFld);

        insertBtn = new JButton("Insert");
        c.add(insertBtn);

        deleteBtn = new JButton("Delete");
        c.add(deleteBtn);

        displayBtn = new JButton("Display");
        c.add(displayBtn);

        displayOneBtn = new JButton("DisplayOne");
        c.add(displayOneBtn);

        hideBtn = new JButton("Hide");
        c.add(hideBtn);

        clearBtn = new JButton("Clear");
        c.add(clearBtn);

        messagesLbl = new JLabel("Messages:");
        messagesLbl.setFont(f2);
        c.add(messagesLbl);

        messagesFld = new JTextField(30);
        c.add(messagesFld);

        //Event Listeners
        insertBtn.addActionListener(new EventHandler());
        deleteBtn.addActionListener(new EventHandler());
        displayBtn.addActionListener(new EventHandler());
        displayOneBtn.addActionListener(new EventHandler());
        hideBtn.addActionListener(new EventHandler());
        clearBtn.addActionListener(new EventHandler());

  }//end constructor      

private class EventHandler implements ActionListener
{
  public void actionPerformed(ActionEvent ev)
  {

        if (ev.getSource() == insertBtn)
        {
              input = idFld.getText();
              idInput = Integer.parseInt(input);

              input = priceFld.getText();
              priceInput = Double.parseDouble(input);

              input = numInStockFld.getText();
              numInStockInput = Integer.parseInt(input);

              input = codeFld.getText();
              codeInput = Integer.parseInt(input);

              insert(idInput, priceInput, numInStockInput, 
                     codeInput); 

              if (responseCode == 0)
              {
                    messagesFld.setText("Array is full. Cannot insert book ID: " + 
                                        idInput);
              }
              else if (responseCode == 1)
              {
                    messagesFld.setText("Succesful insertion of " + idInput);
              }
              else if (responseCode == -1)
              {
                    messagesFld.setText("Duplicate ID: " + idInput);
              }                          



        }

        else if (ev.getSource() == deleteBtn)
        {
              input = idFld.getText();
              idInput = Integer.parseInt(input);

              delete(idInput);

              if (responseCode == 1)
              {      
                    messagesFld.setText("Successful delete of book ID: " +
                                        idInput);
              }
              else if (responseCode == -1)
              {
                    messagesFld.setText("ID: " + idInput + " not found.");
              }                                

        }

        else if (ev.getSource() == displayBtn)
        {
              for (index = 0; index < bookArray.length; index++)
              {
                    bookArray[index].display();
              }      
        }

        else if (ev.getSource() == displayOneBtn)
        {
              input = idFld.getText();
              idInput = Integer.parseInt(input);

              for (index = 0; index < bookArray.length; index++)
              {
                    if (bookArray[index].getID() == idInput)
                    {
                          bookArray[index].getID();
                          bookArray[index].getPrice();
                          bookArray[index].getNumberInStock();
                          bookArray[index].getCode();

                          messagesFld.setText("id: " + bookArray[index].getID() +
                                              "  Price: " + bookArray[index].getPrice() +
                                              "  Number In Stock: " + bookArray[index].getNumberInStock() +
                                              "  Code: " + bookArray[index].getCode()); 
                    }
              }      

        }      

        else if (ev.getSource() == hideBtn)
        {

        }

        else if (ev.getSource() == clearBtn)
        {
              idFld.setText("");
              priceFld.setText("");
              numInStockFld.setText("");
              codeFld.setText("");
              messagesFld.setText("");
              repaint();
        }

  }//End actionPerformed

}//End handler

  //insert method, called when insert button is pressed
  public int insert(int iD, double prc, int numInStock, int code)
  {
        if (numItems == 10)
        {
              System.out.println("\nThe Array is full, please delete an entry");

              responseCode = 0;
              return responseCode;
        }      

        for (index = 0; index < bookArray.length; index++)
        {
              if (bookArray[index].getID() == iD)
              {
                    System.out.println("\nThat ID already exists");

                    responseCode = -1;
                    return responseCode;
              }
              else if (bookArray[index].getID() == 0)
              {
                    bookArray[index] = new BOOKItem(iD, prc, numInStock, code);
                    numItems++; 

                    System.out.println("\n" + idInput + "\n" + priceInput + "\n" + 
                                       numInStockInput + "\n" + codeInput + "\n" + index);
                    System.out.println("\nID: " + bookArray[index].getID());
                    System.out.println("Price: " + bookArray[index].getPrice());
                    System.out.println("NIS: " + bookArray[index].getNumberInStock());
                    System.out.println("Code: " + bookArray[index].getCode());
                    System.out.println("Items in Array: " + numItems); 

                    responseCode = 1;
                    return responseCode;
              }               

        }

        return responseCode;

  }//end insert method 

  //Delete method, called when delete button is pressed
  public int delete(int id)
  {
        for (index = 0; index < bookArray.length; index++)
        {
              if (bookArray[index].getID() == id)
              {
                    bookArray[index].setID(0);
                    bookArray[index].setPrice(0);
                    bookArray[index].setStock(0);
                    bookArray[index].setCode(0);
                    numItems--;
                    System.out.println("\nSuccessful deletion");

                    responseCode = 1;
                    return responseCode;
              }               

        }

        responseCode = -1;
        return responseCode;

  }//end delete method


}//end app                                                                 

Answer 1

在“隐藏”按钮的 ActionListener 中，基本代码为:

JButton button = (JButton)e.getSource();
Window window = SwingUtilities.windowForComponent( button );
JFrame frame = (JFrame)window;
frame.setState(JFrame.ICONIFIED);

这样您就不会依赖于任何标识您的框架的实例变量。使用事件的源对象是使监听器通用且灵活的好方法。