How to use CheckBoxTableCell in TableViewerColumn

Question

I'm unable to find any examples that use CheckBoxTableCell in a TableViewerColumn if someone could provide me with an example implementation I would be very grateful.

I already have a working model that shows some string values but I'm unable to represent a boolean value as a checkbox.

Is it even possible to show anything else except a String in a TableViewerColumn?

Answer 1

The solution described above is perfectly ok. But there is an alternative solution for displaying checkboxes in a TableViewerColumn which allows you to draw a native checkbox instead of using your own images. You can simply create a new ColumnLabelProvider which renders the native images for you.

The source code for this alternative implementation on this example:

http://publicsvn.bestsolution.at/repos/java/at.bestsolution.jface/branches/3_3_support/src/at/bestsolution/jface/viewers/EmulatedNativeCheckBoxLabelProvider.java

Here is the code I have used in one of my projects with a small tweak which allows the combo box to be centered:

import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.viewers.ColumnViewer;
import org.eclipse.jface.viewers.OwnerDrawLabelProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.TableItem;

/**
 * Emulates a native checkbox in a column label provider which is also centered
 * on screen. This should also work well, in case the field is editable.
 * 
 * @author Gil Fernandes
 *
 */
public abstract class EmulatedNativeCheckBoxLabelProvider extends OwnerDrawLabelProvider {

    private static final String CHECKED_KEY = "CHECKED";

    private static final String UNCHECK_KEY = "UNCHECKED";

    private Image image;

    public EmulatedNativeCheckBoxLabelProvider(ColumnViewer viewer) {
        if (JFaceResources.getImageRegistry().getDescriptor(CHECKED_KEY) == null) {
            Shell shell = viewer.getControl().getShell();
            JFaceResources.getImageRegistry().put(UNCHECK_KEY, makeShot(shell, false, viewer));
            JFaceResources.getImageRegistry().put(CHECKED_KEY, makeShot(shell, true, viewer));
        }
    }

    private Image makeShot(Shell shell, boolean type, ColumnViewer viewer) {
        Shell s = new Shell(shell, SWT.NO_TRIM);
        Button b = new Button(s, SWT.CHECK);
        b.setSelection(type);
        Point bsize = b.computeSize(SWT.DEFAULT, SWT.DEFAULT);
        b.setSize(bsize);
        b.setLocation(0, 0);
        s.setSize(bsize);
        s.open();

        GC gc = new GC(b);
        Image image = new Image(shell.getDisplay(), bsize.x, bsize.y);
        gc.copyArea(image, 0, 0);
        gc.dispose();

        s.close();

        return image;
    }

    public Image getImage(Object element) {
        return JFaceResources.getImageRegistry().getDescriptor(isChecked(element) ? CHECKED_KEY : UNCHECK_KEY)
                .createImage();
    }

    @Override
    protected void paint(Event event, Object element) {

        image = getImage(element);
        if (image != null) {
            Rectangle bounds = ((TableItem) event.item)
                    .getBounds(event.index);
            Rectangle imgBounds = image.getBounds();
            bounds.width /= 2;
            bounds.width -= imgBounds.width / 2;
            bounds.height /= 2;
            bounds.height -= imgBounds.height / 2;

            int x = bounds.width > 0 ? bounds.x + bounds.width : bounds.x;
            int y = bounds.height > 0 ? bounds.y + bounds.height : bounds.y;

            event.gc.drawImage(image, x, y);
        }
    }

    protected abstract boolean isChecked(Object element);

    @Override
    protected void measure(Event event, Object element) {
    }
}

This is how it looks like:

You can then use this column label provider like this:

mappingRoutingColumn.setLabelProvider(new EmulatedNativeCheckBoxLabelProvider(viewer, viewer.getTable(), 2) {

    @Override
    protected boolean isChecked(Object element) {
        return ((MappingTypeData) element).isRouting();
    }

});

Answer 2

Here is an example with a checkbox in the TableViewerColumn. It uses an image to represent a bolean in the cell.

It creates a custom view which extends ViewPart with two static fields to hold the image :

Image CHECKED = Activator.getImageDescriptor("icons/checked.gif").createImage();
Image UNCHECKED = Activator.getImageDescriptor("icons/unchecked.gif").createImage();

Then in the createColumns method just return one of the images depending in the value of the boolean :

col.setLabelProvider(new ColumnLabelProvider() {
  @Override
  public String getText(Object element) {
    return null;
  }

  @Override
  public Image getImage(Object element) {
    if (((Person) element).isMarried()) {
      return CHECKED;
    } else {
      return UNCHECKED;
    }
  }
});

Please check the link given above for more details.

If you want an editable checkbox, you need to create an EditingSupport object for the column you want to have a checkbox.

Here is an example :

public class CheckBoxColumnEditingSupport extends EditingSupport {

    private TableViewer tableViewer;

    public CheckBoxColumnEditingSupport(TableViewer viewer) {
        super(viewer);
        this.tableViewer = viewer;
    }

    @Override
    protected CellEditor getCellEditor(Object o) {
        return new CheckboxCellEditor(null, SWT.CHECK);
    }

    @Override
    protected boolean canEdit(Object o) {
        return true;
    }

    @Override
    protected Object getValue(Object o) {
        ORMData ormData = (ORMData) o;
        return ormData.isOrmIndicator();
    }

    @Override
    protected void setValue(Object element, Object value) {
        ORMData ormData = (ORMData) element;
        ormData.setOrmIndicator((Boolean) value);
        tableViewer.refresh();
    }
}

And then add that editing support to specific column in your table:

tableViewerColumn.setEditingSupport(new CheckBoxColumnEditingSupport (myTableViewer));

See this turotial on how to use Column Editing Support. Also this detailed post on How to add an editable checkbox at JFace TableViewer