Unable to remove panels from a frame

[Raghavan Chockalingam]

I would like to switch between screens so I thought switching btw panels is a good idea but I am not really able to remove panels and put new panels into the frame. I appreciate any kind of help in this context....thanks

the code which does this in my program is...

void displayPanel(String panelName){
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.HORIZONTAL;
gc.gridx = 2;
gc.gridy = 2;
if(panelName.compareTo("loginPanel") == 0){
System.out.println("Login panel is to be shown:");
//this.remove(requestPanel);
//this.remove(responsePanel);
this.removeAll();
//this.getContentPane().add(this.loginPanel, gc);
}

}
  

This is the full working program:

import java.io.*;
 
import javax.swing.*;
import java.awt.*;
 
import java.awt.event.*;
 
import javax.swing.BorderFactory; 
import javax.swing.border.Border;
import javax.swing.border.TitledBorder;
import javax.swing.border.EtchedBorder;
 
/**
* Mail Client - Connects to a mail server and downloads mail/s on user's request
*
*
*
*
*
*
*/
class JavaFrame extends JFrame{
 
JPanel requestPanel = new JPanel(); //request panel
JPanel responsePanel = new JPanel(); //response panel
JPanel loginPanel = new JPanel(); //login panel
JPanel configurationPanel = new JPanel(); //configuration panel
 
JTextArea requestTextArea = new JTextArea();
JTextArea responseTextArea = new JTextArea();
JTextArea sentCommands = new JTextArea();
 
JLabel requestLabel = new JLabel("Send commands to the mail server");
JLabel responseLabel = new JLabel("Received response from the mail server");
JLabel sentCommandsLabel = new JLabel("Commands sent to server");
 
JButton sendRequest = new JButton("Send to server");
JButton loginButton = new JButton("Log in to server");
JButton configureButton = new JButton("Update server configuration");
 
JMenuBar menuBar = new JMenuBar();
 
String storeCommands = ""; //the string that holds all the commands typed
 
public JavaFrame(String title){
super(title);
 
this.setJMenuBar(menuBar);
addMenus();
 
this.setDefaultLookAndFeelDecorated(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
 

void displayPanel(String panelName){
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.HORIZONTAL;
gc.gridx = 2;
gc.gridy = 2;
if(panelName.compareTo("loginPanel") == 0){
System.out.println("Login panel is to be shown:");
//this.remove(requestPanel);
//this.remove(responsePanel);
this.removeAll();
//this.getContentPane().add(this.loginPanel, gc);
}

}
 
void addMenus(){
JMenu fileMenu = new JMenu("File");
JMenuItem menuItem;
 
//add menu to menu bar and set hot key
this.menuBar.add(fileMenu);
fileMenu.setMnemonic(KeyEvent.VK_F);
 
//add menu items
menuItem = new JMenuItem("Configure Server Details");
menuItem.setMnemonic(KeyEvent.VK_C);
fileMenu.add(menuItem);
 
menuItem = new JMenuItem("Login to Server");
menuItem.setMnemonic(KeyEvent.VK_L);
fileMenu.add(menuItem);
menuItem.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
displayPanel("loginPanel");
}
});
 
menuItem = new JMenuItem("Exit Application");
menuItem.setMnemonic(KeyEvent.VK_X);
fileMenu.add(menuItem);
menuItem.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println("You have opted to exit the application now!!!");
addToSentCommands("You have opted to exit the application now!!!");
//System.exit(1);
}
});
 

}
 
void addToSentCommands(String command){
this.storeCommands = this.storeCommands + command + "\n";
this.sentCommands.setText(this.storeCommands);
}
 

void createRequestPanel(GridBagConstraints gc){
 
//set layouts and sizes for panels
requestPanel.setLayout(new GridBagLayout());
 
//set colors for labels
requestLabel.setOpaque(true);
requestLabel.setBackground(Color.YELLOW);
 
sentCommandsLabel.setOpaque(true);
sentCommandsLabel.setBackground(Color.YELLOW);
 
//set borders for labels
requestLabel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
sentCommandsLabel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
 

//set labels for textareas
requestLabel.setLabelFor(requestTextArea);
sentCommandsLabel.setLabelFor(sentCommands);
 
//add labels to panels
//requestLabel
gc.ipady = 10; 
gc.gridx = 0;
gc.gridy = 2;
requestPanel.add(requestLabel, gc);
 
//sentCommands label
gc.gridx = 0;
gc.gridy = 0;
requestPanel.add(sentCommandsLabel, gc);
 
//set colors for textareas
requestTextArea.setBackground(new Color(200, 100, 100));
requestTextArea.setForeground(Color.WHITE);
 

//set rows and columns for textareas
requestTextArea.setRows(3);
requestTextArea.setColumns(40);
 
sentCommands.setRows(5);
sentCommands.setColumns(40);
 
//add textareas to panels
//requestTextArea
gc.gridx = 0;
gc.gridy = 3;
requestPanel.add(requestTextArea, gc);
 
//sentCommands text area
gc.gridx = 0;
gc.gridy = 1;
requestPanel.add(sentCommands, gc);
 
//add button to panel
gc.gridwidth = 1;
gc.gridx = 1;
gc.gridy = 4;
requestPanel.add(sendRequest, gc);
sendRequest.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
System.out.println(e.toString());
sendCommandsToServer();
 
}
});
 
}
 

void createResponsePanel(GridBagConstraints gc){
//set layouts and sizes for panels
responsePanel.setLayout(new GridBagLayout());
 
//set colors for labels
responseLabel.setOpaque(true);
responseLabel.setBackground(Color.YELLOW);
 
//set borders for labels
responseLabel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
 
//set labels for textareas
responseLabel.setLabelFor(responseTextArea);
 
//add labels to panels
//responseLabel
gc.gridx = 0;
gc.gridy = 0;
responsePanel.add(responseLabel, gc);
 
//set colors for textareas
responseTextArea.setBackground(Color.WHITE);
responseTextArea.setForeground(Color.RED);
 
//set borders for labels
requestTextArea.setBorder(BorderFactory.createLineBorder(Color.BLACK));
responseTextArea.setBorder(BorderFactory.createLineBorder(Color.BLACK));
 
//set rows and columns for textareas
responseTextArea.setRows(10);
responseTextArea.setColumns(40);
 

System.out.println(responseTextArea.getRows());
System.out.println(responseTextArea.getColumns());
 

//set properties for text areas
responseTextArea.setEnabled(false);
sentCommands.setEnabled(false);

 
//add textareas to panels
//responseTextArea
gc.gridx = 0;
gc.gridy = 1;
responsePanel.add(responseTextArea, gc);
 

}
 

void createLoginPanel(GridBagConstraints gc){
JLabel loginLabel = new JLabel("Login Form");
JLabel commentsLabel = new JLabel("Please provide a valid username and password");
JLabel tempLabel;
 
final JTextField userNameText = new JTextField();
final JTextField passwordText = new JTextField();

//final String userName = "", password = "";
 
//set layouts and sizes for panels
loginPanel.setLayout(new GridBagLayout());
 

gc.gridwidth = 3;
gc.gridx = 0;
gc.gridy = 0;
loginPanel.add(loginLabel, gc);
 
gc.gridwidth = 3;
gc.gridx = 0;
gc.gridy = 1;
loginPanel.add(commentsLabel, gc);
 
gc.gridwidth = 1;
gc.gridx = 0;
gc.gridy = 2;
loginPanel.add(new JLabel("User Name"), gc);
 
gc.gridwidth = 1;
gc.gridx = 1;
gc.gridy = 2;
loginPanel.add(userNameText, gc);
 
gc.gridwidth = 1;
gc.gridx = 0;
gc.gridy = 3;
loginPanel.add(new JLabel("Password"), gc);
 
gc.gridwidth = 1;
gc.gridx = 1;
gc.gridy = 3;
loginPanel.add(passwordText, gc);
 
loginButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
handleLogin(userNameText.getText(), passwordText.getText());
System.out.println(userNameText.getText() + "=======>" + passwordText.getText());
 
}
});
}
 
void handleLogin(String userName, String password){

}
 
void createConfigurationPanel(GridBagConstraints gc){
}

void sendCommandsToServer(){
responseTextArea.setText(requestTextArea.getText());
}
 
void addComponentsToFrame(GridBagConstraints gc){
//set borders
requestPanel.setBorder(BorderFactory.createEtchedBorder(EtchedBorder.RAISED));
 
//Adding panels to frame
//response panel
gc.gridwidth = 3;
gc.gridx = 0;
gc.gridy = 0;
this.getContentPane().add(responsePanel, gc);
 
//request panel
gc.gridwidth = 0;
gc.gridx = 0;
gc.gridy = 1;
this.getContentPane().add(requestPanel, gc);
 
}
 
}
 

class Interface{
public static void main(String args[]){
JavaFrame newFrame = new JavaFrame("Mail Client");

//set frame's layout
newFrame.setLayout(new GridBagLayout());
GridBagConstraints gc = new GridBagConstraints();
gc.fill = GridBagConstraints.HORIZONTAL;
 

//add all components to panels and panels to frame
newFrame.addComponentsToFrame(gc);
newFrame.createRequestPanel(gc);
newFrame.createResponsePanel(gc);
newFrame.createLoginPanel(gc);
newFrame.createConfigurationPanel(gc);


//frame's visibility and size
newFrame.setVisible(true);
newFrame.pack();
}
}
  

[Joe Ess]

Try to post small code samples. Most people will see more than 20 lines of code and move on to the next question.
You can solve your problem with a Card Layout

[Raghavan Chockalingam]

I can not change layout again. Already I had problems with sizing in GridLayout so I chose GridBagLayout, now you are asking me to change to Card layout and that requires work.
1. Could you tell me what exactly is the problem why does not it work???

2. I just want to know how you guys switch btw screens or do you change frames or panels or remove/add components in panels

You commented to put short codes, if you see the post again, I have the given the piece of code which does not work and have given the whole program for users to run and see how it works and where the problem is....hope you do understand me...

[Raghavan Chockalingam]

I have solved the problem. The problem was because of the absence of pack() statement after I remove/add panels to the frame.

[Sloan Bowman]

you should use the panel.validate() also if you have the chance this will help you.