Develop Reference

Convert an incrementing/changing String value to existing incremental variable name of JButtons to modify their properties in java

Simplified: How to make String value to call specific existed JButton variable name in java?
I'm trying to make a non-ordinary Tic-Tac-Toe game...
Anyway, what I will post here is not really the whole concept of that. I just want to make it simple: I have 9 square jButtons named (3 by 3) (and maybe allow user to make 4x4, 5x5, 10x10 etc. via settings in future):
[markbox_00_00] / [markbox_00_01] / [markbox_00_02]
[markbox_01_00] / [markbox_01_01] / [markbox_01_02]
[markbox_02_00] / [markbox_02_01] / [markbox_02_02]
[btnSave] / [btnUndoActions]
where the first two digit represent the row and the next two is the column; and a save button (btnSave) and undo button(btnUndoActions).
Each markbox have default spring value of "0", when I click it turns "1"; and when I click "1" it turns "0". When you press undo button it will reset to last save.
Here is some of my simplified line of codes:
private byte markboxColLimit = 3, markboxRowLimit = 3, row, col;
private byte[][] saveNumber = new byte[markboxRowLimit][markboxColLimit];
private String buttonName;
public Astral_TicTacToe() {
initComponents();
/* I want something like this, but using a for loop based on markboxColLimit and
markboxRowLimit as limits */
markbox_00_00.setText("0");
markbox_00_01.setText("0");
markbox_00_02.setText("0");
markbox_01_00.setText("0");
markbox_01_01.setText("0");
markbox_01_02.setText("0");
markbox_02_00.setText("0");
markbox_02_01.setText("0");
markbox_02_02.setText("0");
/* I know the line below is wrong... what I'm trying is to avoid
* repetitiveness by looping and dynamically calling the variable
* name of JButtons, or in other ways...
*/
/* Attempting to make an alternative code from above (trying to make a loop instead) */
for(row = 0; row < markboxRowLimit; row++){
for(col = 0; col < markboxColLimit; col++){
buttonName = "markbox_0" + Byte.toString(row) + "_0" + Byte.toString(col);
buttonName.setText("0");
}
}
}
private void btnUndoActionsActionPerformed(java.awt.event.ActionEvent evt) {
markbox_00_00.setText(Byte.toString(saveNumber[0][0]));
markbox_00_01.setText(Byte.toString(saveNumber[0][1]));
markbox_00_02.setText(Byte.toString(saveNumber[0][2]));
markbox_01_00.setText(Byte.toString(saveNumber[1][0]));
markbox_01_01.setText(Byte.toString(saveNumber[1][1]));
markbox_01_02.setText(Byte.toString(saveNumber[1][2]));
markbox_02_00.setText(Byte.toString(saveNumber[2][0]));
markbox_02_01.setText(Byte.toString(saveNumber[2][1]));
markbox_02_02.setText(Byte.toString(saveNumber[2][2]));
}
private void btnSaveActionPerformed(java.awt.event.ActionEvent evt) {
saveNumber[0][0] = Byte.parseByte(markbox_00_00.getText());
saveNumber[0][1] = Byte.parseByte(markbox_00_01.getText());
saveNumber[0][2] = Byte.parseByte(markbox_00_02.getText());
saveNumber[1][0] = Byte.parseByte(markbox_01_00.getText());
saveNumber[1][1] = Byte.parseByte(markbox_01_01.getText());
saveNumber[1][2] = Byte.parseByte(markbox_01_00.getText());
saveNumber[2][0] = Byte.parseByte(markbox_02_00.getText());
saveNumber[2][1] = Byte.parseByte(markbox_02_01.getText());
saveNumber[2][2] = Byte.parseByte(markbox_02_02.getText());
}
private void markbox_00_00ActionPerformed(java.awt.event.ActionEvent evt) {
if("0".equals(markbox_00_00.getText()))
markbox_00_00.setText("1");
else
markbox_00_00.setText("0");
}
private void markbox_00_01ActionPerformed(java.awt.event.ActionEvent evt) {
if("0".equals(markbox_00_01.getText()))
markbox_00_00.setText("1");
else
markbox_00_00.setText("0");
}
....
private void markbox_02_02ActionPerformed(java.awt.event.ActionEvent evt) {
if("0".equals(markbox_00_00.getText()))
markbox_02_02.setText("1");
else
markbox_02_02.setText("0");
}
In short: how can I make String a specific variable name of JButton for calling/accessing/editing for their properties?
Example:
buttonName = markbox_01_02;
buttonName.setText("2");
is equavalent to markbox_01_02.getText("2");
I really appreciate the help, thank you...
P.S. I use to make JFrame in NetBeans Design (just click and drag the objects in palette window like JPanel, JButton, etc., so I don't type the code manually except making my own logical Method).

You probably need to redo your program and rephrase your question because it's kind of unclear where you're stuck that's why I wrote this answer as a Community Wiki.
The following program creates a GridLayout for the board and add 2 JButtons below it which contain "Save" and "Undo" buttons.
Whenever you press a button it will change it's text to 0 or 1 depending on the previous state of the button, and "Undo" button will undo last clic the same way, if it was 0 it will become 1 and viceversa.
I guess you should read How to write an ActionListener before copy-pasting this example, understand what it says and try to understand how this program works.
The logic to "Save" button is up to you 'cause I'm not sure what you wanna do there and I'm not gonna write all the code for you. This is made only for you to get an idea on how to handle events.
Also, the logic to end the game is left to you for the same reasons as the "Save" button.
I wish I knew how to record my screen in Ubuntu and save as GIF but here's a screenshot on how this program looks like:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class TicTacToe implements ActionListener {
JFrame frame;
JButton buttons[];
JPanel pane, buttonPane;
boolean pressed[];
JButton save, undo;
int n = -1;
public void actionPerformed(ActionEvent e) {
for (int i = 0; i < buttons.length; i++) {
if(e.getSource() == buttons[i]) {
pressed[i] = !pressed[i];
buttons[i].setText(pressed[i] ? "1" : "0");
n = i;
break;
}
}
}
public TicTacToe () {
frame = new JFrame("Tic Tac Toe Game");
buttons = new JButton[9];
pane = new JPanel(new GridLayout(3, 3));
pressed = new boolean[9];
buttonPane = new JPanel(new FlowLayout());
save = new JButton("Save");
undo = new JButton("Undo");
for (int i = 0; i < buttons.length; i++) {
buttons[i] = new JButton("0");
pressed[i] = false;
}
for (JButton b : buttons) {
b.addActionListener(this);
pane.add(b);
}
undo.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
if (n == -1) {
return;
}
pressed[n] = !pressed[n];
buttons[n].setText(pressed[n] ? "1" : "0");
}
});
buttonPane.add(save);
buttonPane.add(undo);
frame.add(pane, BorderLayout.PAGE_START);
frame.add(buttonPane, BorderLayout.CENTER);
frame.pack();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
public static void main (String args[]) {
new TicTacToe();
}
}

JTable#scrollRectToVisible in combination with JSplitPlane shows the wrong row

When I call JTable#scrollRectToVisible, the row I want to show is hidden underneath the header in certain situations.
The rest of this question only makes sense when using the following code. This is a very simply program which I use to illustrate the problem. It shows a UI containing a JSplitPane with in the upper part some control buttons, and the lower part contains a JTable wrapped in a JScrollPane (see screenshots at the bottom of this post).
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableModel;
public class DividerTest {
private final JSplitPane fSplitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
private final JTable fTable;
private final JScrollPane fScrollPane;
private boolean fHideTable = false;
public DividerTest() {
fTable = new JTable( createTableModel(50));
fScrollPane = new JScrollPane(fTable);
fSplitPane.setBottomComponent(fScrollPane);
fSplitPane.setTopComponent(createControlsPanel());
fSplitPane.setDividerLocation(0.5);
}
private JPanel createControlsPanel(){
JPanel result = new JPanel();
result.setLayout(new BoxLayout(result, BoxLayout.PAGE_AXIS));
final JCheckBox checkBox = new JCheckBox("Make table invisible before adjusting divider");
checkBox.addItemListener(new ItemListener() {
#Override
public void itemStateChanged(ItemEvent e) {
fHideTable = checkBox.isSelected();
}
});
result.add(checkBox);
JButton upperRow = new JButton("Select row 10");
upperRow.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
selectRowInTableAndScroll(10);
}
});
result.add(upperRow);
JButton lowerRow = new JButton("Select row 45");
lowerRow.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
selectRowInTableAndScroll(45);
}
});
result.add(lowerRow);
JButton hideBottom = new JButton("Hide bottom");
hideBottom.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
if (fHideTable) {
fScrollPane.setVisible(false);
}
fSplitPane.setDividerLocation(1.0);
}
});
result.add(hideBottom);
JButton showBottom = new JButton("Show bottom");
showBottom.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
fScrollPane.setVisible(true);
fSplitPane.setDividerLocation(0.5);
}
});
result.add(showBottom);
return result;
}
private void selectRowInTableAndScroll( int aRowIndex ){
fTable.clearSelection();
fTable.getSelectionModel().addSelectionInterval(aRowIndex, aRowIndex);
fTable.scrollRectToVisible(fTable.getCellRect(aRowIndex, 0, true));
}
public JComponent getUI(){
return fSplitPane;
}
private TableModel createTableModel(int aNumberOfRows){
Object[][] data = new Object[aNumberOfRows][1];
for( int i = 0; i < aNumberOfRows; i++ ){
data[i] = new String[]{"Row" + i};
}
return new DefaultTableModel(data, new String[]{"Column"});
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame("Test frame");
frame.getContentPane().add(new DividerTest().getUI());
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
}
});
}
}
Unwanted behavior
Run the above code
Press the "Select row 10": row 10 is selected and visible
Press the "Select row 45": row 45 is selected and visible
Click the "Hide bottom" button. This will adjust the divider of the JSplitPane so that only the upper panel is visible
Click the "Select row 10" button. You see of course nothing because the table is not yet visible
Click the "Show bottom" button. The divider is adjusted, but row 10 is hidden underneath the header. I expected it to be visible without needing to scroll.
Wanted behavior
Repeat the steps from above, but make sure the "Make table invisible before adjusting divider" checkbox is selected. This will call setVisible(false) on the JScrollPane around the JTable before hiding the bottom panel.
By doing this, in the last step row 10 will be visible as the top most row, which is what I want. I just do not want to turn the scrollpane invisible: in my real application, the divider is adjusted in an animated way and as such you want to keep the table visible during the animation.
Screenshots
Unwanted: row 10 is invisible after performing the aforementioned steps
Wanted: row 10 is visible after performing the aforementioned steps
Environment
I do not think it will matter, but just in case: I am using JDK7 on a Linux system.

This seems to be caused by the way how the JViewport handles the scrollRectToVisible calls for the cases that its size is smaller than the desired rectangle. It contains a (somewhat fuzzy, but probably related) comment in the JavaDocs:
Note that this method will not scroll outside of the valid viewport; for example, if contentRect is larger than the viewport, scrolling will be confined to the viewport's bounds.
I did not go though the complete code and do all the maths and check all the cases. So a warning: The following explainations contain quite same hand-waving. But a simplified description of what this means for me in this particular case:
When the bottom part is hidden (by setting the divider location accordingly), then this height of the JScrollPane and its JViewport is 0. Now, when requesting to scrollRectToVisible with a rectangle that has a height of 20 (for one table row, as an example), then it will notice that this does not fit. Depending on the current view position of the JViewport, this may cause to viewport to be scrolled so that the bottom of this rectangle is visible.
(You can observe this: Drag the divider location manually, so that approximately half of one table row is visible. When clicking the "Select row 45" button, the upper half of the row will be visible. When clicking the "Select row 10" button, then the lower half of the row will be visible)
One pragmatic solution here that seemed to work for me was to make sure that it will always scroll so that the top of the rectangle is visible (even when the rectangle does not at all fit into the viewport!). Like this:
private void selectRowInTableAndScroll(int aRowIndex)
{
fTable.clearSelection();
fTable.getSelectionModel().addSelectionInterval(aRowIndex, aRowIndex);
Rectangle r = fTable.getCellRect(aRowIndex, 0, true);
r.height = Math.min(fScrollPane.getHeight(), r.height);
fTable.scrollRectToVisible(r);
}
But I can't promise that this will have the desired effect for you, when an animation comes into play...

Not exactly sure what the scrollRectToVisible() is doing.
You might be able to use the JViewport.setViewPosition(...) method.
Rectangle r = fTable.getCellRect(aRowIndex, 0, true);
Point p = new Point(r.x, r.y);
fScrollPane.getViewport().setViewPosition( p );
In this case the selected row will always be shown at the top of the viewport (if possible). So the viewport will always scroll unless the selected row is current at the top. Using this approach if the first row is at the top of the viewport and you select the 10th row the viewport will scroll to display the 10th row at the top.
However, this behaviour is slightly different than using the scrollRectToVisible() method. When using the scrollRectToVisible() method the viewport when only scrolled when the rectangle is not in the visible part of the viewport. Using this approach if the first row is at the top of the viewport and you select the 10th row the viewport will NOT scroll since the 10th row is already visible in the viewport.
Don't know if this change in functionality is acceptable or not.
Note if you don't want to viewport to automatically scroll when you select a row you could try something like:
JViewport viewport = fScrollPane.getViewport();
Rectangle viewRect = viewport.getViewRect();
Rectangle r = fTable.getCellRect(aRowIndex, 0, true);
Point p = new Point(r.x, r.y);
if (! viewRect.contains(p))
viewport.setViewPosition( p );

Issues creating java GUI with while loop

I am creating a java GUI which is a fortune teller. The GUI will spit out one of twelve fortunes every time you click the "get my fortune" button, the strings will never repeat back to back, can can repeat later after other strings have gone before it. I have made already for the most part. But now I am having some trouble creating the while loops to display the strings without repeating. I have looked at my book which didn't really help. If you guys could point me in the right direction,it would be much appreciated. Thanks!
I entered all of the code so you can see the variables used. But my question starts at class RndButtonListener.
package FortuneTellerRunner;
import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Random;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
/**
*
* #author a3cal_000
*/
class FortuneTellerFrame extends JFrame
{
final private JPanel mainPnl, titlePnl, displayPnl, buttonPnl, imagePnl;
final private JButton quitBtn, rndBtn;
final private JLabel titleLbl, iconLbl;
final private JTextArea displayTa;
final private JScrollPane scroller;
public String[] fortune = new String [12];
int newIndex, oldIndex;
private static final int HEIGHT = 250;
private static final int WIDTH = 450;
public FortuneTellerFrame()
{
setSize(WIDTH, HEIGHT);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainPnl = new JPanel();
mainPnl.setLayout(new BorderLayout());
displayPnl = new JPanel();
buttonPnl = new JPanel();
titlePnl = new JPanel();
ImageIcon icon = new ImageIcon("FortuneTellerIcon.JPEG");
iconLbl = new JLabel(icon);
titleLbl = new JLabel("Fortune Teller!");
displayTa = new JTextArea();
imagePnl = new JPanel();
scroller = new JScrollPane();
// Create the layout of the title panel
titlePnl.setLayout(new GridLayout(2,1));
add(mainPnl);
// Set the label to the panel.
titlePnl.add(titleLbl);
titlePnl.add(iconLbl);
// add the panel to the main panel.
mainPnl.add(titlePnl, BorderLayout.NORTH);
mainPnl.add(scroller, BorderLayout.CENTER);
mainPnl.add(displayTa, BorderLayout.CENTER);
// Create the "Get my fortune button.
rndBtn = new JButton("Get My Fortune!");
quitBtn = new JButton("Quit");
// Add the buttons to the buttonPnl in grid layout.
buttonPnl.add(rndBtn);
buttonPnl.add(quitBtn);
// Create the grid layout for the button panel.
buttonPnl.setLayout( new GridLayout(1, 2));
// Add the button panel to the grid layout, South.
mainPnl.add(buttonPnl, BorderLayout.SOUTH);
ActionListener listener = new RndButtonListener();
rndBtn.addActionListener(listener);
quitBtn.addActionListener(listener);
}
class RndButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent evt)
{
fortune[0] = "He who throws dirt is losing ground.";
fortune[1] = "You will find the love of your life in food.";
fortune[2] = "Do or do not, there is no try.";
fortune[3] = "Tomorrow is a better day to try anything of importance.";
fortune[4] = "Life's not about how hard you can hit, but how hard you can get hit and keep moving forward.";
fortune[5] = "You can't be late until you show up.";
fortune[6] = "If you think things can't get worse it's probably only because you lack sufficent imagination.";
fortune[7] = "If youre at the top it means you have further to fall.";
fortune[8] = "Even in last place, youre still in the race.";
fortune[9] = "The road to riches is paved on the failures of others.";
fortune[10] = "If you feel like your going no where, get off the treadmill.";
fortune[11] = "Thinking about going to the gym is just as good as going.";
Random rnd = new Random(fortune.length);
do
{
newIndex = rnd.nextInt(fortune.length);
}
while(newIndex == oldIndex);
do
{
System.out.println(fortune[newIndex]);
displayTa.append(fortune[newIndex] + "||");
displayTa.updateUI();
mainPnl.updateUI();
oldIndex = newIndex;
}
while(newIndex != oldIndex);
class QuitButtonListener implements ActionListener
{
public void actionPerformed(ActionEvent evt)
{
System.exit(0);
}
}
}
}
}

The basic problem is you are re-creating the Random with the same seed each time, which is generally creating the same random sequence over and over again.
Instead try using...
do {
newIndex = (int) Math.round(Math.random() * (fortune.length - 1));
} while (newIndex == oldIndex);
You also don't need the second loop, it's just clutter that confuses the situation.
You may also find that...
displayTa.append(fortune[newIndex] + "\n");
produces nicer output (IMHO)
You may also wish to take a look at How to use Scroll Panes

Your program run fine, but this is a problem, fortune.length is a random seed which return me only 6 and 8 when I later called Random.nextInt().
Random rnd = new Random(fortune.length);
Do it this way
Random rnd = new Random();
and also consider the formatting solution given by MadProgrammer.

Random() gives you same number pattern. Try Random(System.currentTimeMillis()). It uses current time as seed, so you can get real random numbers.

I did something similar to this just today, so let's see if I can remember... I made an ArrayList of type int of how many items I had (fortunes)
ArrayList<Integer> fortuneSeq = new ArrayList<Integer>();
Then add in some numbers starting from 0 to code for the fortunes.
for(int i = 0; i < fortune.length; i++) {
fortuneSeq.add(i);
}
Then I used the shuffle() method from the Collections class to randomize the list.
Collections.shuffle(fortuneSeq);
After that, just loop through to access the fortunes.
for(int i = 0; i < fortune.length; i++) {
System.out.println(fortune[fortuneSeq.get(i)]);
//...
}
Edit: Silly autocorrect, you don't like programmers.
Edit: Fixed some furtunes instead of fortunes and fixed println statement.

How to change string length (calculating its width in pixel) when changing window size and strange behaviour of JLabel

I have JLabel which I would like to change its size while I resize the window. When JLabel contains String which is too big, the String should be shortened, with right part visible and adds dots on the left hand side of the String.
My JLabel is inside innerPanel which is a header in middlePanel which is added to outerPanel. So when I resize window I use listener on outerPanel in that way:
outerPanel.addComponentListener(new ComponentListener() {
#Override
public void componentResized(ComponentEvent evt) {
int width = ((JPanel) evt.getSource()).getWidth();
windowSize = width;
refresh();
}
// [...] other not used override methods
});
refresh() repaints view and creates new middlePanel where is called class which creates innerPanel where is located my JLabel:
Public class InnerPanel extends JPanel {
private int maxSize;
String string = "<VERY_LONG_STRING>";
private static final int DEFAULT_INDEND_PIXEL = 70;
public InnerPanel(int windowSize) {
maxSize = windowSize - DEFAULT_INDENT_PIXEL;
createPanel();
}
private createPanel() {
// [...] gridbag and GridBagConstraints implementation
String shortString = countString();
JLabel label = new JLabel(shortString);
add(label,gc);
}
private String countString() {
int index = 0;
boolean toBig = true;
StringBuilder sb = new StringBuilder(string);
while(toBig) {
Rectangle2d rect = // [...] code which creates rectangle around text from sb.toString()
// I have no access to repo at home but if it's important I can paste it tomorrow
if(rect.getWidth() > maxSize)
sb.deleteCharAt(0);
else
toBig = false;
}
return sb.toString();
}
}
That's works fine in general, bacause it do resize JLabel in one step when I enlarge window in width. But the problem is appear when I try to reduce the window in width. In this case componentResized() calculate width step by step (and it's called multiple times), gradually decreases width by some amount of pixels till it reach real window size. It's behave in that way even thow I change window size in one step from maximum size to 800. Whole process is so slow, that it takes around a second to fit string to window size. So it looks bit like an animation.
The problem is very rare to me, bacause width in componentResized() method is calculeted step by step only when I assign windowSize variable.
When I give windowSize fixed size like for example 500 - componentResized() is called only onces - with correct width indicated real window size (!!) - and there's no its step by step decrease!
It's look like width variable which is assigned by ((JPanel) evt.getSource()).getWidth() knows that windowSize is used to dynamically change size of JLabel component even before first call of refresh() method.
If anyone have an idea what is going on here - I will be very appreciate for help.

You may be able to adapt one of the approaches shown here to better effect. As shown here, the ellipsis is supplied by the label's UI delegate via a call to SwingUtilities2.clipString(), which appends the clipString. Rather than re-invent the label UI, use TextLayout to determine the required geometry, prepend the ellipsis, and handle the alignment in a table or list renderer, as shown here.

SWT - Creating a grid of numbers that I'd like to be able to tab through with keyboard

This problem has been driving me CRAZY!!! Using SWT, I'd like to create a grid of numbers that I can tab traverse using the keyboard. I'd like to be able to select and click into each cell (not just on the numbers) to perform some action. In other words, I'm looking for a way to make a true FLAT button. The goal here is to make the grid accessible with screen readers such that when a cell has focus, the screen reader will read the number value in the middle of each cell.
Originally, I created a GridLayout with a set of button controls to display the number values. This actually worked but I didn't want the buttons to look like buttons. The SWT.FLAT style for button controls doesn't work on Windows operating systems. This is caused by an OS limitation.
Next I then tried converting all buttons to labels but since label controls cant take focus, I couldn't implement any type of tab traversal. Next I tried replacing all labels with read-only text controls. I was able to re-introduce the tab traversal/focusing but I can't get the text to display in the dead-center of each cell. This is actually caused by a SWT limitation. The SWT.CENTER style for text controls only affects the horizontal alignment. Text controls can't be vertically aligned.
So finally, someone told me to wrap each read-only text control in a Composite. This allowed me to center the read-only text controls but I don't know how to make the composite itself to be tab traversed.
Any ideas on how I can get this done or how I can make controls that typically dont take focus (like composite, canvas, label) actually take focus so I can tab traverse each control with my keyboard?
I'm fairly new to java and SWT so I apologize if some of this is confusing. Many thanks. This is how I've constructed each of my cells thus far (I've replaced the read-only text with CLabel controls):
Display display = new Display();
Shell shell = new Shell(display);
GridLayout gridLayout = new GridLayout(5, false);
gridLayout.marginWidth = 0;
gridLayout.marginHeight = 0;
gridLayout.horizontalSpacing = 1;
gridLayout.verticalSpacing = 1;
shell.setLayout(gridLayout);
Composite resetComp = new Composite(shell, SWT.BORDER);
GridData compgridData = new GridData(SWT.CENTER, SWT.CENTER, true, true);
GridData resetGD = new GridData(SWT.FILL, SWT.FILL, false, false);
resetGD.verticalSpan = 2;
resetComp.setLayoutData(resetGD);
resetComp.setLayout(new GridLayout(1, false));
CLabel resetCLabel = new CLabel(resetComp, SWT.SHADOW_OUT | SWT.CENTER);
resetCLabel.setText("Reset"); //$NON-NLS-1$
resetCLabel.setLayoutData(compgridData);
resetCLabel.setBackground(Display.getCurrent().getSystemColor(SWT.COLOR_RED)); //$NON-NLS-1$
resetComp.setToolTipText(resetCLabel.getText());

Here is a trick, maybe it will suits you: create each button inside a Composite, and set the size of the Button bigger than its parent Composite; This way, the border of button is not visible, because outside of its parent composite.
private static final int GRID_SIZE = 5;
private static final int CELL_SIZE = 40;
private static final int PADDING = 3;
public static void main (String [] args) {
Display display = new Display ();
Shell shell = new Shell (display);
shell.setLayout(new GridLayout(GRID_SIZE, true));
for (int i = 0; i < GRID_SIZE * GRID_SIZE; i++) {
createButton(shell, i+1);
}
shell.pack ();
shell.open ();
while (!shell.isDisposed ()) {
if (!display.readAndDispatch ()) display.sleep ();
}
display.dispose ();
}
private static void createButton(Shell shell, final int number) {
Composite c = new Composite(shell, SWT.NONE);
c.setLayoutData(new GridData(CELL_SIZE, CELL_SIZE));
Button button = new Button(c, SWT.NONE);
button.setText(Integer.toString(number));
button.setBounds(-PADDING, -PADDING, CELL_SIZE + 2 * PADDING, CELL_SIZE + 2 * PADDING);
button.addSelectionListener(new SelectionAdapter() {
public void widgetSelected(SelectionEvent e) {
System.err.println("click on " + number);
}
});
}
It fulfills your requirement: focus, centered. The result may be more or less nice depending on the Windows version (try to change the padding, or add a border to the Composite, it may look nicer).