[news.eclipse.platform.swt] GridData problem

[hortiz@xxxxxxxxx (hortiz)]

Hi,

I have a problem with GridData / GridLayout configuration.
I use in my application (which runs on Linux) a general tool bar which 
contains :
- a command line,

- a progress bar,

- and a set of buttons which is sometimes visible, sometimes not.


My problem occurs when hiding the parent composite of the buttons : all 
others widgets are moved to the top of the parent composite, whereas they 
were correctly vertical aligned before.

Here a snippet to show the problem : click on show/hide button, and you 
will see what I mean.

Thanks,
Helene

// ----------------------------
// THE MAIN CLASS
// ----------------------------
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class GridDataProblem {
   
   private static Display display;
   private static Composite mainComposite;
   private static SampleComposite sampleComposite;
   private static boolean show = false;

   public static void main(String[] args) {
       
		display = new Display();
		Shell shell = new Shell(display);
		
		shell.setLayout(new GridLayout());
		
		mainComposite = new Composite(shell, SWT.BORDER);
       GridData gridData = new GridData();
       gridData.grabExcessHorizontalSpace = true;
       gridData.grabExcessVerticalSpace = false;
       gridData.horizontalAlignment = GridData.FILL;
       gridData.verticalAlignment = GridData.FILL;
		mainComposite.setLayoutData(gridData);
		mainComposite.setLayout(new GridLayout());
		
		sampleComposite = new SampleComposite(mainComposite, SWT.NONE);
		
		Button hideShow = new Button(mainComposite, SWT.PUSH);
		hideShow.setText("Hide/Show");
		
		hideShow.addSelectionListener(new SelectionAdapter() {
           public void widgetSelected(SelectionEvent arg0) {
               sampleComposite.refresh(show);
               show = !show;
           }
		});
		
		shell.setSize(800,200);
		shell.open();

		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
		display.dispose();
   }
}

// ----------------------------
// A SPECIFIC COMPOSITE
// ----------------------------
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.ProgressBar;
import org.eclipse.swt.widgets.Text;

public final class SampleComposite extends Composite {
   
   private Text commandLine;
   private ProgressBar progressBar;
   private Composite buttonsComposite;
   private Button pauseButton;
   private Button startStopButton;
   
   public SampleComposite(Composite parent, int style) {
       super(parent, style | SWT.NO_REDRAW_RESIZE);
       this.setLayout(getGridLayout(4));
       createContent();
       setGridData();
       this.setBackground(getDisplay().getSystemColor(SWT.COLOR_GREEN));
   }
   

   public void refresh(boolean show) {
       if (show) {
           showButtons();
       } else {
           hideButtons();
       }
       this.layout();
   }
   

   private void showButtons() {
       buttonsComposite.setVisible(true);
       GridData gridData = (GridData)progressBar.getLayoutData();
       gridData.horizontalSpan = 1;
   }
   
   
   private void hideButtons() {
       buttonsComposite.setVisible(false);
       GridData gridData = (GridData)progressBar.getLayoutData();
       gridData.horizontalSpan = 2;
   }

   
   private void createContent() {
       createCommandLine();
       createStatusAreaProgressBar();
       createButtons();
   }
   
   
   private void createCommandLine() {
       Label commandLineLabel = new Label(this, SWT.NONE);
       commandLineLabel.setText("Command :");
       commandLineLabel.setLayoutData(getNewGridData(false));
       this.commandLine = new Text(this, SWT.BORDER);
       this.commandLine.setLayoutData(getNewGridData(true));
   }
   
   
   private void createStatusAreaProgressBar() {
       this.progressBar = new ProgressBar(this, SWT.BORDER|SWT.SMOOTH);
       this.progressBar.setMaximum(100);
       this.progressBar.setMinimum(0);
       this.progressBar.setLayoutData(getNewGridData(true));
   }
   
   
   private void createButtons() {
       buttonsComposite = new Composite(this, SWT.NONE);
       buttonsComposite.setLayout(getGridLayout(2));
       buttonsComposite.setLayoutData(getNewGridData(false));
       
       this.pauseButton = new Button(buttonsComposite, SWT.PUSH);
       this.pauseButton.setText("Pause");
       this.pauseButton.setLayoutData(getNewGridData(false));
       
       this.startStopButton = new Button(buttonsComposite, SWT.PUSH);
       this.startStopButton.setText("Start");
       this.startStopButton.setLayoutData(getNewGridData(false));
   }
   
   
   private void setGridData() {
       GridData statusGridData = new GridData();
       statusGridData.grabExcessHorizontalSpace = true;
       statusGridData.grabExcessVerticalSpace = false;
       statusGridData.horizontalAlignment = GridData.FILL;
       statusGridData.verticalAlignment = GridData.FILL;
       this.setLayoutData(statusGridData);
   }
   
   private GridData getNewGridData(boolean grabExcessHorizontalSpace) {
       GridData gridData = new GridData();
       gridData.grabExcessHorizontalSpace = grabExcessHorizontalSpace;
       gridData.grabExcessVerticalSpace = false;
       gridData.horizontalAlignment = GridData.FILL;
       gridData.verticalAlignment = GridData.CENTER;
       return gridData;		
   }
   
	public GridLayout getGridLayout(int nbColumns) {
		GridLayout gridLayout = new GridLayout();
		gridLayout.numColumns = nbColumns;
		gridLayout.horizontalSpacing = 8;
		gridLayout.verticalSpacing = 8;
		return gridLayout;
	}
}