GridBagLayout question

[Akhil Jain]

Hi all,

I was trying my hands on using GridBagLayout to lay down my components.
Can anyone tell me... how to place a button and textfields with some constant width and height using this layout, so that even if the window is maximised, they stay to be of the same size.


i am trying to create this sort of structure
basically a form.
---------------------------------------------------
Label 1 TEXTFIELD
BUTTON
label 2 TEXTFIELD
---------------------------------------------------

Regards
Akhil

[Craig Wood]

import java.awt.*;
import javax.swing.*;
 
public class LeftGBLayout {
    private JPanel getContent() {
        JPanel panel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(2,5,2,2);
        gbc.weightx = 0;
        gbc.anchor = GridBagConstraints.WEST;
        panel.add(new JLabel("Label 1"), gbc);
        gbc.gridwidth = GridBagConstraints.REMAINDER;
        gbc.weightx = 1.0;
        panel.add(new JTextField(12), gbc);
        gbc.gridwidth = 2;
        gbc.weightx = 0;
        gbc.gridy = 1;
        panel.add(new JButton("Button"), gbc);
        gbc.gridwidth = 1;
        gbc.gridy = 2;
        panel.add(new JLabel("Label 2"), gbc);
        gbc.weightx = 1.0;
        panel.add(new JTextField(12), gbc);
        return panel;
    }
 
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new LeftGBLayout().getContent());
        f.setSize(400,400);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}

[Akhil Jain]

hi craig,

thanks for that code....can you tell me what i am doing wrong here....

 ............
.................
................
final JTextField toRangeField,fromRangeField,singleFinderField;
 
 
buildConstraints(gbc, 1, 0, 1, 1, 0.5, 0,
GridBagConstraints.HORIZONTAL, GridBagConstraints.LINE_START);
singleFinderField = new JTextField();
singleFinderField.setMaximumSize(new Dimension(30, 10));
singleFinderField.setEnabled(true);
gbl.setConstraints(singleFinderField, gbc);
 
buildConstraints(gbc, 1, 1, 1, 1, 0.5, 0,
GridBagConstraints.HORIZONTAL, GridBagConstraints.LINE_START);
fromRangeField = new JTextField();
fromRangeField.setMaximumSize(new Dimension(30, 10));
fromRangeField.setEnabled(false);
fromRangeField.setText("Enter From Range");
gbl.setConstraints(fromRangeField, gbc);
 
buildConstraints(gbc, 3, 1, 1, 1, 0.5, 0,
GridBagConstraints.HORIZONTAL, GridBagConstraints.LINE_START);
toRangeField = new JTextField();
toRangeField.setMaximumSize(new Dimension(30, 10));
toRangeField.setEnabled(false);
toRangeField.setText("Enter To Range");
gbl.setConstraints(toRangeField, gbc);
 
buildConstraints(gbc, 2, 1, 1, 1, 0.5, 0,
GridBagConstraints.HORIZONTAL, GridBagConstraints.CENTER);
final JLabel rangeSeperatorLabel = new JLabel();
rangeSeperatorLabel.setText("-");
gbl.setConstraints(rangeSeperatorLabel, gbc);
 
buildConstraints(gbc, 1, 2, 2, 1, 0.2, 0,
GridBagConstraints.HORIZONTAL, GridBagConstraints.CENTER);
final JButton getRecordsButton = new JButton();
getRecordsButton.setText("Go");
getRecordsButton.setMaximumSize(new Dimension(30, 10));
gbl.setConstraints(getRecordsButton, gbc);
 
final JRadioButton lookForRecordRadioButton, lookForRecordsRadioButton;
 
lookForRecordRadioButton = new JRadioButton();
 
buildConstraints(gbc, 0, 0, 1, 1, 0.3, 0, GridBagConstraints.NONE,
GridBagConstraints.LINE_START);
lookForRecordRadioButton.setText("Search by record number");
lookForRecordRadioButton.setActionCommand("Record");
lookForRecordRadioButton.setBackground(Color.WHITE);
gbl.setConstraints(lookForRecordRadioButton, gbc);
 
lookForRecordsRadioButton = new JRadioButton();
 
buildConstraints(gbc, 0, 1, 1, 1, 0.3, 0, GridBagConstraints.NONE,
GridBagConstraints.LINE_START);
lookForRecordsRadioButton.setText("Search by record range");
lookForRecordsRadioButton.setActionCommand("Records");
lookForRecordsRadioButton.setBackground(Color.WHITE);
gbl.setConstraints(lookForRecordsRadioButton, gbc);
 
// A button group that ensures we select only one option.
final ButtonGroup group = new ButtonGroup();
group.add(lookForRecordRadioButton);
group.add(lookForRecordsRadioButton);
 
group.setSelected(lookForRecordRadioButton.getModel(), true);
 
// add all searchPanel components
searchPanel.getInsets(new Insets(10, 10, 10, 10));
 
searchPanel.add(lookForRecordRadioButton);
searchPanel.add(singleFinderField);
searchPanel.add(lookForRecordsRadioButton);
searchPanel.add(fromRangeField);
searchPanel.add(rangeSeperatorLabel);
searchPanel.add(toRangeField);
searchPanel.add(getRecordsButton);
..............
.............
 
private void buildConstraints(GridBagConstraints gbc, int x, int y, int w,
int h, double wx, double wy, int fill, int anchor) {
 
gbc.gridx = x; // start cell in a row
gbc.gridy = y; // start cell in a column
gbc.gridwidth = w; // how many column does the control occupy in the
// row
gbc.gridheight = h; // how many column does the control occupy in the
// column
gbc.weightx = wx; // relative horizontal size
gbc.weighty = wy; // relative vertical size
gbc.fill = fill; // the way how the control fills cells
gbc.anchor = anchor; // alignment
 
}
   

structure which i am looking for to create with above code is this:--->



i want this structure to remain as it is...even when i maximize the window.I am simply not able to do this.i have drawn this image using Absolute Layout.........but i dont want to use Absolute anymore....how can i do the same thing using GridBagLayout....can you help me out with this.?

[ November 09, 2007: Message edited by: Akhil Jain ]
[ November 09, 2007: Message edited by: Akhil Jain ]

[Craig Wood]

Your layout image shows the layout centered instead of alligned to the west/left. To
center this layout change all the anchor constraints form LINE_START to CENTER.
Use the insets constraints to alter the spacing among components.
Managing the weightx constraint is how we keep the components all aligned to the left. The
weightx values for all components should be zero except for the last component in each
row.

import java.awt.*;
import javax.swing.*;
 
public class LeftGBLayout2 {
    private JPanel getContent() {
        GridBagLayout gbl = new GridBagLayout();
        JPanel searchPanel = new JPanel(gbl);
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(2,2,2,2);
 
        // Explore JTextField sizing difficulties:
        JTextField tf1 = new JTextField();
        Dimension d1 = tf1.getPreferredSize();
        JTextField tf2 = new JTextField(" ");
        Dimension d2 = tf2.getPreferredSize();
        System.out.printf("tf1 prefSize = [%d, %d]  tf2 = [%d, %d]%n",
                           d1.width, d1.height, d2.width, d2.height);
        // Height spec for JTextFields looks too small.
        // The designers recommend that we supply a columns value
        // in the constructor for JTextFields for proper sizing:
        JTextField tf3 = new JTextField(8);
        Dimension d3 = tf3.getPreferredSize();
        System.out.printf("tf3 prefSize = [%d, %d]%n", d3.width, d3.height);
        // Let's try this on for size:
        Dimension d = new Dimension(d3);
 
//        buildConstraints(gbc, 1, 0, 1, 1, 0.5, 0,  // width=1
        buildConstraints(gbc, 1, 0, 4, 1, 1.0, 0,
//                         GridBagConstraints.HORIZONTAL,
                         GridBagConstraints.NONE,
                         GridBagConstraints.LINE_START);
        JTextField singleFinderField = new JTextField();
//        singleFinderField.setMaximumSize(new Dimension(30, 10));
        singleFinderField.setPreferredSize(d);
        singleFinderField.setEnabled(true);
        gbl.setConstraints(singleFinderField, gbc);
 
//        buildConstraints(gbc, 1, 1, 1, 1, 0.5, 0,
        buildConstraints(gbc, 1, 1, 1, 1, 0, 0,
//                         GridBagConstraints.HORIZONTAL,
                         GridBagConstraints.NONE,
                         GridBagConstraints.LINE_START);
        JTextField fromRangeField = new JTextField();
//        fromRangeField.setMaximumSize(new Dimension(30, 10));
        fromRangeField.setPreferredSize(d);
        fromRangeField.setEnabled(false);
        fromRangeField.setText("Enter From Range");
        gbl.setConstraints(fromRangeField, gbc);
 
//        buildConstraints(gbc, 3, 1, 1, 1, 0.5, 0,
        buildConstraints(gbc, 3, 1, 1, 1, 0, 0,
//                         GridBagConstraints.HORIZONTAL,
                         GridBagConstraints.NONE,
                         GridBagConstraints.LINE_START);
        JTextField toRangeField = new JTextField();
//        toRangeField.setMaximumSize(new Dimension(30, 10));
        toRangeField.setPreferredSize(d);
        toRangeField.setEnabled(false);
        toRangeField.setText("Enter To Range");
        gbl.setConstraints(toRangeField, gbc);
 
//        buildConstraints(gbc, 2, 1, 1, 1, 0.5, 0,
        buildConstraints(gbc, 2, 1, 1, 1, 0, 0,
//                         GridBagConstraints.HORIZONTAL,
                         GridBagConstraints.NONE,
//                         GridBagConstraints.CENTER);
                         GridBagConstraints.LINE_START);
        final JLabel rangeSeperatorLabel = new JLabel();
        rangeSeperatorLabel.setText("-");
        gbl.setConstraints(rangeSeperatorLabel, gbc);
 
//        buildConstraints(gbc, 1, 2, 2, 1, 0.2, 0,   // x=1, y=2, width=2
        buildConstraints(gbc, 4, 1, 1, 1, 1.0, 0,
//                         GridBagConstraints.HORIZONTAL,
                         GridBagConstraints.NONE,
 //                        GridBagConstraints.CENTER);
                         GridBagConstraints.LINE_START);
        final JButton getRecordsButton = new JButton();
        getRecordsButton.setText("Go");
//        getRecordsButton.setMaximumSize(new Dimension(30, 10));
//        getRecordsButton.setPreferredSize(new Dimension(30, 10));
        gbl.setConstraints(getRecordsButton, gbc);
 
//        buildConstraints(gbc, 0, 0, 1, 1, 0.3, 0,
        buildConstraints(gbc, 0, 0, 1, 1, 0, 0,
                         GridBagConstraints.NONE,
                         GridBagConstraints.LINE_START);
        JRadioButton lookForRecordRadioButton = new JRadioButton();
        lookForRecordRadioButton.setText("Search by record number");
        lookForRecordRadioButton.setActionCommand("Record");
        lookForRecordRadioButton.setBackground(Color.WHITE);
        gbl.setConstraints(lookForRecordRadioButton, gbc);
 
//        buildConstraints(gbc, 0, 1, 1, 1, 0.3, 0,
        buildConstraints(gbc, 0, 1, 1, 1, 0, 0,
                         GridBagConstraints.NONE,
                         GridBagConstraints.LINE_START);
        JRadioButton lookForRecordsRadioButton = new JRadioButton();
        lookForRecordsRadioButton.setText("Search by record range");
        lookForRecordsRadioButton.setActionCommand("Records");
        lookForRecordsRadioButton.setBackground(Color.WHITE);
        gbl.setConstraints(lookForRecordsRadioButton, gbc);
 
        // A button group that ensures we select only one option.
        final ButtonGroup group = new ButtonGroup();
        group.add(lookForRecordRadioButton);
        group.add(lookForRecordsRadioButton);
 
        group.setSelected(lookForRecordRadioButton.getModel(), true);
 
        // add all searchPanel components
//        searchPanel.getInsets(new Insets(10, 10, 10, 10));
 
        searchPanel.add(lookForRecordRadioButton);
        searchPanel.add(singleFinderField);
        searchPanel.add(lookForRecordsRadioButton);
        searchPanel.add(fromRangeField);
        searchPanel.add(rangeSeperatorLabel);
        searchPanel.add(toRangeField);
        searchPanel.add(getRecordsButton);
        return searchPanel;
    }
 
    private void buildConstraints(GridBagConstraints gbc, int x, int y, int w,
                            int h, double wx, double wy, int fill, int anchor) {
        gbc.gridx = x;        // start cell in a row
        gbc.gridy = y;        // start cell in a column
        gbc.gridwidth = w;    // how many column does the control occupy in the row
        gbc.gridheight = h;   // how many rows does the control occupy in column
        gbc.weightx = wx;     // relative horizontal size
        gbc.weighty = wy;     // relative vertical size
        gbc.fill = fill;      // the way how the control fills cells
        gbc.anchor = anchor;  // alignment
    }
 
    public static void main(String[] args) {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.getContentPane().add(new LeftGBLayout2().getContent());
        f.setSize(500,200);
        f.setLocation(200,200);
        f.setVisible(true);
    }
}

Edit:
Your layout image shows the layout centered instead of alligned to the west/left. To
center this layout change all the anchor constraints form LINE_START to CENTER.
And set all weightx constraints to zero.
[ November 09, 2007: Message edited by: Craig Wood ]