I have a little Java swing GUI with a GridBagLayout. I have set the GridBagConstraints.fill = GridBagConstraints.BOTH but don't want that my buttons or text fields to get resized vertically. Furthermore, I only want my JTextArea to be resized and tried putting in maximum size for the components I don't want to size up, but it is not working. Any ideas on how I can make the GBC.fill only applicable for some components?
Reproducible example:
public class Main {
static JFrame frame = new JFrame("Create New Entry");
static JPanel wrapper = new JPanel();
static JTextField title = new JTextField(20);
static JLabel titleLabel = new JLabel("Title");
static JTextField username = new JTextField(20);
static JLabel usernameLabel = new JLabel("Username");
static JTextField email = new JTextField(20);
static JLabel emailLabel = new JLabel("Email Address");
static JPasswordField password = new JPasswordField(20);
static JLabel passwordLabel = new JLabel("Password");
static JButton generatePassword = new JButton("Generate Password");
static JPasswordField confirmPassword = new JPasswordField();
static JLabel confirmPasswordLabel = new JLabel("Confirm Password");
static JToggleButton showPassword = new JToggleButton("Show Password");
static JButton submit = new JButton("Submit Entry");
static JLabel notesLabel = new JLabel("Notes");
static JTextArea textArea = new JTextArea(5, 0);
static JScrollPane scrollPane = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
public static void main(String[] args) {
GridBagConstraints gbc = new GridBagConstraints();
wrapper.setLayout(new GridBagLayout());
gbc.gridwidth = GridBagConstraints.RELATIVE;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.insets = new Insets(10, 10, 10, 10);
gbc.weightx = 1;
gbc.weighty = 1;
gbc.gridwidth = 1;
gbc.gridx = 0;
gbc.gridy = 0;
wrapper.add(titleLabel, gbc);
gbc.gridx = 1;
gbc.gridwidth = 2;
wrapper.add(title, gbc);
gbc.gridwidth = 1;
gbc.gridx = 0;
gbc.gridy = 1;
wrapper.add(usernameLabel, gbc);
gbc.gridx = 1;
gbc.gridwidth = 2;
wrapper.add(username, gbc);
gbc.gridwidth = 1;
gbc.gridx = 0;
gbc.gridy = 2;
wrapper.add(emailLabel, gbc);
gbc.gridx = 1;
gbc.gridwidth = 2;
wrapper.add(email, gbc);
gbc.gridwidth = 1;
gbc.gridx = 0;
gbc.gridy = 3;
wrapper.add(passwordLabel, gbc);
gbc.gridx = 1;
wrapper.add(password, gbc);
gbc.gridx = 2;
wrapper.add(generatePassword, gbc);
gbc.gridwidth = 1;
gbc.gridx = 0;
gbc.gridy = 4;
wrapper.add(confirmPasswordLabel, gbc);
gbc.gridx = 1;
wrapper.add(confirmPassword, gbc);
gbc.gridx = 2;
wrapper.add(showPassword, gbc);
gbc.gridx = 0;
gbc.gridy = 5;
wrapper.add(notesLabel, gbc);
gbc.fill = GridBagConstraints.BOTH;
gbc.gridx = 1;
gbc.gridwidth = 2;
wrapper.add(scrollPane, gbc);
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.gridwidth = 3;
gbc.gridy = 6;
wrapper.add(submit, gbc);
password.setPreferredSize(new Dimension(300, 26));
confirmPassword.setPreferredSize(new Dimension(300, 26));
title.setPreferredSize(new Dimension(300, 26));
username.setPreferredSize(new Dimension(300, 26));
email.setPreferredSize(new Dimension(300, 26));
frame.add(wrapper);
frame.pack();
frame.setMinimumSize(frame.getSize());
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
Any ideas on how I can make the GBC.fill only applicable for some components?
Yes. Don't have all components use a GridBagConstraints object whose fill field is .BOTH. Each component should be added with its own GBC object, and the ones you want filled both horizontally and vertically should have the fill property set to .BOTH, and the components that should only expand horizontally should have GBC fill field of .HORIZONTAL. When I use the GridBagLayout, I often create helper method(s) for creating constraint objects, methods that know what settings to use based on parameters passed into them, and I suggest that you consider doing the same.
As Abra mentions, yes, you can modify a GridBagConstraints (GBC) object, by changing the settings of one or more fields as necessary, and I sometimes do this too, but more often, I use helper methods to create GBC objects on the fly. It just works better for me that way.
For example:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.*;
public class Main2 extends JPanel {
private static final long serialVersionUID = 1L;
private static final int FIELD_COLS = 20;
private static final int TA_ROWS = 10;
private static final int INGS_GAP = 10;
private JLabel titleLabel = new JLabel("Title");
private JLabel userNameLabel = new JLabel("Username");
private JLabel emailAddrLabel = new JLabel("EmailAddress");
private JLabel passwordLabel = new JLabel("Password");
private JLabel confirmPasswordLabel = new JLabel("Confirm Password");
private JLabel notesLabel = new JLabel("Notes");
private JTextField titleField = new JTextField(FIELD_COLS);
private JTextField userNameField = new JTextField(FIELD_COLS);
private JTextField emailField = new JTextField(FIELD_COLS);
private JPasswordField passwordField = new JPasswordField(FIELD_COLS);
private JPasswordField confirmPasswordField = new JPasswordField(FIELD_COLS);
private JTextArea NotesArea = new JTextArea(TA_ROWS, FIELD_COLS);
private JScrollPane textAreaScrollPane = new JScrollPane(NotesArea);
private JButton generatePasswordBtn = new JButton("Generate Password");
private JButton showPasswordBtn = new JButton("Show Password");
private JButton submitEntryBtn = new JButton("Submit Entry");
public Main2() {
setLayout(new GridBagLayout());
// basic GBC use
int row = 0;
GridBagConstraints gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
add(titleLabel, gbc);
gbc = createGbc(1, row, GridBagConstraints.HORIZONTAL, 2, 1);
add(titleField, gbc);
row++;
gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
add(userNameLabel, gbc);
gbc = createGbc(1, row, GridBagConstraints.HORIZONTAL, 2, 1);
add(userNameField, gbc);
row++;
gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
add(emailAddrLabel, gbc);
gbc = createGbc(1, row, GridBagConstraints.HORIZONTAL, 2, 1);
add(emailField, gbc);
row++;
gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
add(passwordLabel, gbc);
gbc = createGbc(1, row, GridBagConstraints.HORIZONTAL);
add(passwordField, gbc);
gbc = createGbc(2, row, GridBagConstraints.HORIZONTAL);
add(generatePasswordBtn, gbc);
row++;
gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
add(confirmPasswordLabel, gbc);
gbc = createGbc(1, row, GridBagConstraints.HORIZONTAL);
add(confirmPasswordField, gbc);
gbc = createGbc(2, row, GridBagConstraints.HORIZONTAL);
add(showPasswordBtn, gbc);
// here we set the GBC weighty to non-0 value to allow vertical expansion
// of added components
row++;
int txtAreaRows = TA_ROWS;
gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
gbc.anchor = GridBagConstraints.WEST;
gbc.weighty = 1.0;
add(notesLabel, gbc);
gbc = createGbc(1, row, GridBagConstraints.BOTH, 2, txtAreaRows);
gbc.weighty = 1.0;
add(textAreaScrollPane, gbc);
textAreaScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
row += txtAreaRows;
gbc = createGbc(0, row, GridBagConstraints.HORIZONTAL);
add(new JLabel(""), gbc);
gbc = createGbc(1, row, GridBagConstraints.HORIZONTAL, 2, 1);
add(submitEntryBtn, gbc);
}
private static GridBagConstraints createGbc(int x, int y, int fill, int width, int height) {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = x;
gbc.gridy = y;
gbc.gridwidth = width;
gbc.gridheight = height;
gbc.fill = fill;
// allow horizontal expansion *unless* at left-most position in row
gbc.weightx = x == 0 ? 0.0 : 1.0;
gbc.weighty = 0.0; // default to no vertical expansion
gbc.insets = new Insets(INGS_GAP, INGS_GAP, INGS_GAP, INGS_GAP);
return gbc;
}
private static GridBagConstraints createGbc(int x, int y, int fill) {
return createGbc(x, y, fill, 1, 1);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
Main2 mainPanel = new Main2();
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}