| Pressing "Arrow Down" key right after focusing and selection of some cell in Grid programm [message #587100] |
Thu, 27 December 2007 05:30 |
Eclipse User |
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Originally posted by: vye.maconomy.dk
Hi guys,
When I try to focus and select some cell (using Grid API)
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 :))
to reproduce the problem. Here is the snippet:
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 code 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 code 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 code line was inserted instead
// of the line commented out above.
shell.pack();
shell.open ();
while (!shell.isDisposed()) {
if (!display.readAndDispatch ()) display.sleep ();
}
display.dispose ();
}
}
Does somebody know why it might be a problem?
Best regards,
Vadym Yepishov
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