Java Tutorial/Swing/GridBagConstraints

Adding Components with a Relative X Position

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class RelativeX {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridy = 0;
    pane.add(new JButton("First row"), gbc);
    gbc.gridx = GridBagConstraints.RELATIVE;
    gbc.gridy = 1;
    pane.add(new JButton("Second row, first column"), gbc);
    pane.add(new JButton("Second row, second column"), gbc);
    pane.add(new JButton("Second row, third column"), gbc);
    gbc.gridy = 2;
    pane.add(new JButton("Third row"), gbc);
    f.setSize(600, 300);
    f.setVisible(true);
  }
}

Adding Components with a Relative Y Position

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class RelativeY {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 0;
    pane.add(new JButton("First column"), gbc);
    gbc.gridx = 1;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("Second column, first row"), gbc);
    pane.add(new JButton("Second column, second row"), gbc);
    pane.add(new JButton("Second column, third row"), gbc);
    gbc.gridx = 2;
    pane.add(new JButton("Third column"), gbc);
    f.setSize(500, 300);
    f.setVisible(true);
  }
}

Adding Components with Relative X and Y Coordinates

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class RelativeXY {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 1;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, first column"), gbc);
    pane.add(new JButton("Second row"), gbc);
    pane.add(new JButton("Third row"), gbc);
    gbc.gridx = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, second column"), gbc);
    f.setSize(500, 300);
    f.setVisible(true);
  }
}

A GridBagLayout Example: weightx, weighty

import java.awt.Button;
import java.awt.Frame;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JPanel;
public class Main extends JPanel {
  protected void makebutton(String name, GridBagLayout gridbag, GridBagConstraints c) {
    Button button = new Button(name);
    gridbag.setConstraints(button, c);
    add(button);
  }
  public Main() {
    GridBagLayout gridbag = new GridBagLayout();
    GridBagConstraints c = new GridBagConstraints();
    setLayout(gridbag);
    c.weightx = 1.0;
    c.weighty = 1.0;
    makebutton("Button 1", gridbag, c);
    c.fill = GridBagConstraints.BOTH;
    makebutton("Button 2", gridbag, c);
  }
  public static void main(String args[]) {
    Frame f = new Frame();
    JPanel mgb = new Main();
    f.add("Center", mgb);
    f.pack();
    f.setSize(300, 300);
    f.setVisible(true);
  }
}

A Simple Application That Uses GridBagConstraints.WEST

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class GridBagConstraintsSimplePanel extends JPanel {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.getContentPane().add(new GridBagConstraintsSimplePanel());
    f.setSize(400, 300);
    f.setVisible(true);
  }
  public GridBagConstraintsSimplePanel() {
    super();
    GridBagConstraints constraints = new GridBagConstraints();
    GridBagLayout layout = new GridBagLayout();
    setLayout(layout);
    constraints.anchor = GridBagConstraints.WEST;
    constraints.gridy = 0;
    JLabel label = new JLabel("First name:");
    add(label, constraints);
    JTextField tf = new JTextField(8);
    add(tf, constraints);
    label = new JLabel("Last name:");
    add(label, constraints);
    tf = new JTextField(8);
    add(tf, constraints);
    constraints.gridy = 1;
    label = new JLabel("Address:");
    add(label, constraints);
    tf = new JTextField(10);
    add(tf, constraints);
  }
}

Effects of the fill Constraint

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagLayoutFill {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 0;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("This button"s preferred width " + "is large because its text is long"),
        gbc);
    pane.add(new JButton("Small centered button"), gbc);
    gbc.fill = GridBagConstraints.HORIZONTAL;
    pane.add(new JButton("Expands to fill column width"), gbc);
    f.setSize(400, 300);
    f.setVisible(true);
  }
}

Effects of the gridheight Constraint

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JFrame;
public class GridBagLayoutGridHeight {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    pane.add(new JLabel("First row, first column"), gbc);
    pane.add(new JLabel("First row, second column"), gbc);
    gbc.gridheight = GridBagConstraints.REMAINDER;
    gbc.fill = GridBagConstraints.VERTICAL;
    pane.add(new JLabel("First row, third column"), gbc);
    gbc.gridx = 0;
    gbc.gridheight = 1;
    gbc.fill = GridBagConstraints.NONE;
    pane.add(new JButton("Second row"), gbc);
    pane.add(new JButton("Third row"), gbc);
    f.setSize(600, 300);
    f.setVisible(true);
  }
}

Effects of the gridwidth Constraint

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagLayoutColumnSpan {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 1;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, first column"), gbc);
    pane.add(new JButton("Second row"), gbc);
    gbc.gridwidth = 2;
    pane.add(new JButton("Third row, spans two columns"), gbc);
    gbc.gridwidth = 1;
    gbc.gridx = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, second column"), gbc);
    f.setSize(400, 300);
    f.setVisible(true);
  }
}

Filling the Entire Column

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagLayoutColumnSpanHORIZONTAL {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    gbc.gridx = 1;
    gbc.gridy = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, first column"), gbc);
    pane.add(new JButton("Second row"), gbc);
    gbc.gridwidth = 2;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    pane.add(new JButton("Third row, spans two columns"), gbc);
    gbc.gridwidth = 1;
    gbc.fill = GridBagConstraints.NONE;
    gbc.gridx = GridBagConstraints.RELATIVE;
    pane.add(new JButton("First row, second column"), gbc);
    f.setSize(400, 300);
    f.setVisible(true);
  }
}

Use GridBagLayout to layout RadioButtons

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
public class PizzaGridBagLayout extends JFrame {
  public static void main(String[] args) {
    new PizzaGridBagLayout();
  }
  JTextField name = new JTextField(20), phone = new JTextField(10), address = new JTextField(20);
  JRadioButton small = new JRadioButton("Small"), medium = new JRadioButton("Medium"),
      large = new JRadioButton("Large"), thick = new JRadioButton("Thick"),
      thin = new JRadioButton("Thin");
  JCheckBox pepperoni = new JCheckBox("Pepperoni"), mushrooms = new JCheckBox("Mushrooms"),
      anchovies = new JCheckBox("Anchovies");
  JButton okButton = new JButton("OK"), closeButton = new JButton("Close");
  public PizzaGridBagLayout() {
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JPanel panel1 = new JPanel();
    panel1.setLayout(new GridBagLayout());
    addItem(panel1, new JLabel("Name:"), 0, 0, 1, 1, GridBagConstraints.EAST);
    addItem(panel1, new JLabel("Phone:"), 0, 1, 1, 1, GridBagConstraints.EAST);
    addItem(panel1, new JLabel("Address:"), 0, 2, 1, 1, GridBagConstraints.EAST);
    addItem(panel1, name, 1, 0, 2, 1, GridBagConstraints.WEST);
    addItem(panel1, phone, 1, 1, 1, 1, GridBagConstraints.WEST);
    addItem(panel1, address, 1, 2, 2, 1, GridBagConstraints.WEST);
    Box sizeBox = Box.createVerticalBox();
    ButtonGroup sizeGroup = new ButtonGroup();
    sizeGroup.add(small);
    sizeGroup.add(medium);
    sizeGroup.add(large);
    sizeBox.add(small);
    sizeBox.add(medium);
    sizeBox.add(large);
    sizeBox.setBorder(BorderFactory.createTitledBorder("Size"));
    addItem(panel1, sizeBox, 0, 3, 1, 1, GridBagConstraints.NORTH);
    Box styleBox = Box.createVerticalBox();
    ButtonGroup styleGroup = new ButtonGroup();
    styleGroup.add(thin);
    styleGroup.add(thick);
    styleBox.add(thin);
    styleBox.add(thick);
    styleBox.setBorder(BorderFactory.
    createTitledBorder("Style"));
    addItem(panel1, styleBox, 1, 3, 1, 1, GridBagConstraints.NORTH);
    Box topBox = Box.createVerticalBox();
    ButtonGroup topGroup = new ButtonGroup();
    topGroup.add(pepperoni);
    topGroup.add(mushrooms);
    topGroup.add(anchovies);
    topBox.add(pepperoni);
    topBox.add(mushrooms);
    topBox.add(anchovies);
    topBox.setBorder(BorderFactory.createTitledBorder("Toppings"));
    addItem(panel1, topBox, 2, 3, 1, 1, GridBagConstraints.NORTH);
    Box buttonBox = Box.createHorizontalBox();
    buttonBox.add(okButton);
    buttonBox.add(Box.createHorizontalStrut(20));
    buttonBox.add(closeButton);
    addItem(panel1, buttonBox, 2, 4, 1, 1, GridBagConstraints.NORTH);
    this.add(panel1);
    this.pack();
    this.setVisible(true);
  }
  private void addItem(JPanel p, JComponent c, int x, int y, int width, int height, int align) {
    GridBagConstraints gc = new GridBagConstraints();
    gc.gridx = x;
    gc.gridy = y;
    gc.gridwidth = width;
    gc.gridheight = height;
    gc.weightx = 100.0;
    gc.weighty = 100.0;
    gc.insets = new Insets(5, 5, 5, 5);
    gc.anchor = align;
    gc.fill = GridBagConstraints.NONE;
    p.add(c, gc);
  }
}

Using GridBagConstraints

1. GridBagConstraints specifies how to display a specific component.
2. Every component added to a GridBagLayout container should have a GridBagConstraints object associated with it.
3. Without GridBagConstraints, the GridBagLayout is a blank slate.

import java.awt.ruponent;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagButtons {
  private static final Insets insets = new Insets(0, 0, 0, 0);
  public static void main(final String args[]) {
    final JFrame frame = new JFrame("GridBagLayout");
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setLayout(new GridBagLayout());
    JButton button;
    // Row One - Three Buttons
    button = new JButton("One");
    addComponent(frame, button, 0, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    button = new JButton("Two");
    addComponent(frame, button, 1, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    button = new JButton("Three");
    addComponent(frame, button, 2, 0, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    // Row Two - Two Buttons
    button = new JButton("Four");
    addComponent(frame, button, 0, 1, 2, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    button = new JButton("Five");
    addComponent(frame, button, 2, 1, 1, 2, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    // Row Three - Two Buttons
    button = new JButton("Six");
    addComponent(frame, button, 0, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    button = new JButton("Seven");
    addComponent(frame, button, 1, 2, 1, 1, GridBagConstraints.CENTER, GridBagConstraints.BOTH);
    frame.setSize(500, 200);
    frame.setVisible(true);
  }
  private static void addComponent(Container container, Component component, int gridx, int gridy,
      int gridwidth, int gridheight, int anchor, int fill) {
    GridBagConstraints gbc = new GridBagConstraints(gridx, gridy, gridwidth, gridheight, 1.0, 1.0,
        anchor, fill, insets, 0, 0);
    container.add(component, gbc);
  }
}

Using the REMAINDER Value for a Width

import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
public class GridBagLayoutRemainder {
  public static void main(String[] args) {
    JFrame f = new JFrame();
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    Container pane = f.getContentPane();
    pane.setLayout(new GridBagLayout());
    GridBagConstraints gbc = new GridBagConstraints();
    pane.add(new JButton("First row, first column"), gbc);
    pane.add(new JButton("First row, second column"), gbc);
    pane.add(new JButton("First row, third column"), gbc);
    gbc.gridx = 0;
    pane.add(new JButton("Second row"), gbc);
    gbc.gridwidth = GridBagConstraints.REMAINDER;
    gbc.fill = GridBagConstraints.HORIZONTAL;
    pane.add(new JButton("Third row, gridwidth set to REMAINDER"), gbc);
    f.setSize(600, 300);
    f.setVisible(true);
  }
}