Question

是否可以从JFrame类获取父JPanel个对象
实际上我正在尝试使用NetBeans创建GUI.GUI有一个框架和两个面板 1）登录面板（有两个文本字段和按钮）
2）第二小组
加载JFrame时，我最初在其中添加LoginPanel。

public ParentJFrame() {    //in constructor
        initComponents();
        this.setLayout(new BorderLayout());
        this.setBounds(300,300, 300, 300);
        this.getContentPane().add(new LoginPanel());

    }

点击按钮（LoginPanel）后，我正在尝试从JFrame中删除LoginPanel并添加SecondPanel。
现在我要移除LoginPanel并在SecondPanel类中添加LoginPanel，我可以访问username , password字段，但在这里我无法获取我必须删除的JFrame对象这个组成部分如果我在ParentJFrameClass中尝试此操作，那么我无法访问username , password字段的值。 （因为这是netbeans提供的结构）
那我现在该怎么办？在这种情况下会有什么解决方案
我希望我已经详细解释了这个问题但是如果有什么不清楚请告诉我专家请帮忙

Answer 1

要使用cardlayout在面板之间切换，如下面的代码可能对您有所帮助，您需要对其进行修改以满足您的需求：

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

/**
 * replace the real panel of yours 
 * do the right process
*/

public class CardLayoutLoginDemo  {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable(){

            @Override
            public void run() {
                // TODO Auto-generated method stub
                JFrame frame = new LoginFrame();
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}
class LoginFrame extends JFrame {
   public LoginFrame() {
       super("CardLayout Demo");

        //Create the panel that contains the "cards".
        mainPanel = new JPanel(new CardLayout());
        mainPanel.add(getFirstPanel(), FIRST);
        mainPanel.add(getSecondPanel(), SECOND);
        this.setContentPane(mainPanel);
        this.pack();
   }
   //use your first panel
   private JPanel getFirstPanel() {
       JPanel panel = new JPanel();
       panel.setLayout(new GridLayout(3,2));
       panel.add(new JLabel("Username: "));
       panel.add(new JTextField(10));
       panel.add(new JLabel("password: "));
       panel.add(new JTextField(10));
       JButton btnLogin = new JButton("Login");
       JButton btnCancel = new JButton("Cancel");
       btnLogin.addActionListener(new ActionListener(){

        @Override
        public void actionPerformed(ActionEvent e) {
            // TODO Auto-generated method stub
                CardLayout cl = (CardLayout)(mainPanel.getLayout());
                cl.show(mainPanel, SECOND);
        }
       });
       btnCancel.addActionListener(new ActionListener(){

            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub

            }
        });
       panel.add(btnLogin);
       panel.add(btnCancel);
       return panel;
   }
   //use the second panel
   private JPanel getSecondPanel() {
       JPanel panel = new JPanel();
       panel.setLayout(new GridLayout(2,2));
       panel.add(new JLabel("Second panel"));
       panel.add(new JLabel("other processs"));
       JButton btnOther = new JButton("Ok");
       JButton btnBack = new JButton("Back");
       panel.add(btnOther);
       panel.add(btnBack);
       btnBack.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent e) {
                // TODO Auto-generated method stub
                 CardLayout cl = (CardLayout)(mainPanel.getLayout());
                 cl.show(mainPanel, FIRST);
            }
        });
       return panel;
   }
   private final String FIRST = "First panel";
   private final String SECOND = "Second panel";
   private static final long serialVersionUID = 1L;
   private JPanel mainPanel;
}

从JPanel对象获取父框架对象

1 个答案: