Re: [nebula-dev] Pressing Arrow Down Key right after focusing and select

[Christopher J Gross <chris.gross@xxxxxxxxxx>]

Hi Vadym,

I just tried your snippet and I can't
reproduce the problem.  Your description does sounds familar though.
 Perhaps its a bug that was recently fixed.  Could you try downloading
a recent nightly build and see if that fixes the problem?

Thanks,
-Chris

From:	"Vadym Yepishov" <vye@xxxxxxxxxxx>
To:	<nebula-dev@xxxxxxxxxxx>
Date:	12/26/2007 12:14 PM
Subject:	[nebula-dev] Pressing Arrow Down Key right after focusing and        selection of some cell in Grid programmatically leads to        NullPointerException.

---

Hi guys,
 
When I try to focus and select some cell
in a grid and right after this to press “Arrow Down” key, I have got
NullPointerException.
 
I have used the first snippet of grid (and
changed it a little bit J)
to reproduce the problem. Here is the snippet:
 
package com.maconomy.widgets.snippets;
 
import org.eclipse.nebula.widgets.grid.Grid;
import org.eclipse.nebula.widgets.grid.GridColumn;
import org.eclipse.nebula.widgets.grid.GridItem;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
 
/**
 * Creates a simple grid and a button
for focusing and selection of the first cell
 * of the grid.
 */
public class MxSnippet001GridCellFocusingAndSelection
{
 
  /**
   * Main entry.
   * @param args command line
arguments
   */
  public static void main(final String
[] args) {
      final Display display
= new Display ();
      final Shell shell
= new Shell (display);
//      shell.setLayout(new
FillLayout());
      // The following code
line was inserted instead of the line commented out above in
      // order to be able
to add a button below the grid.
      shell.setLayout(new
GridLayout(1, false));
 
      final Grid grid =
new Grid(shell, SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);
      grid.setHeaderVisible(true);
      final GridColumn column
= new GridColumn(grid, SWT.NONE);
      column.setTree(true);
      column.setText("Column
1");
      column.setWidth(100);
      final GridItem item1
= new GridItem(grid, SWT.NONE);
      item1.setText("Root
Item");
//      final GridItem item2
= new GridItem(item1, SWT.NONE);
      // The following line
was inserted instead of the line commented out above.
      final GridItem item2
= new GridItem(grid, SWT.NONE);
      item2.setText("Second
item");
//      final GridItem item3
= new GridItem(item2, SWT.NONE);
      // The following line
was inserted instead of the line commented out above.
      final GridItem item3
= new GridItem(grid, SWT.NONE);
      item3.setText("Third
Item");
      
      // The following code
is added to demonstrate the defect with the grid cell
      // focusing and selection.

      grid.setCellSelectionEnabled(true);
      // The following button
is used to focus and select the first cell of the grid.
      // Try to press "Arrow
Down" key right after clicking on this button.
      final Button button
= new Button(shell, SWT.BORDER);
      button.addSelectionListener(new
SelectionAdapter() {
        /** {@inheritDoc}
*/
        @Override
        public void
widgetSelected(final SelectionEvent e) {
          grid.forceFocus();
          // We
tried to use the following three code lines in order to both focus and
          // select
some cell of the grid, but as it was found, the third code line leads
          // to
the NullPointerException. If we do not use the third line, the cell is
in
          // fact
selected, but NOT FOCUSED (and focusing is what we need).
          grid.setCellSelection(new
Point(0, 0));
          grid.setFocusItem(grid.getItem(0));
          // When
you comment out the following code line the first cell will be selected
          // but
NOT FOCUSED. You will see that the first cell of the grid being not
          // focused
is indicated by the fact that the border of the cell is not present.
          // If
you do not comment the line the first cell will be both focused and selected,
          // but
pressing "Arrow Down" key leads to NullPointerException.
          grid.setFocusColumn(grid.getColumn(0));
        }
      });
      button.setText("Click
this button to select and focus the first cell of the grid. " +
           
                   "Right
after clicking this button press \"Arrow Down\" key.");
      
      //shell.setSize(200,200);
      // The following line
was inserted instead of the line commented out above.
      shell.pack();
      shell.open ();
      while (!shell.isDisposed())
{
          if (!display.readAndDispatch
()) display.sleep ();
      }
      display.dispose ();
  }
}
 
Do you know why it might be a problem?
 
Best regards,
 
Vadym Yepishov
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