Nebula GridTreeViewer - Is there a way to show the filter like FilteredTree in eclipse?

Question

I am using a Nebula GridTreeViewer for which I need to add filters like eclipse filters. When we go to Window->Preferences, we get a filter on top of the left side tree which says 'type filter text'.

I tried the TreeViewer with the FilteredTree -

final FilteredTree filteredTree = new FilteredTree(parent, SWT.BORDER
                    | SWT.H_SCROLL | SWT.V_SCROLL | SWT.FULL_SELECTION,
                    new MyPatternFilter(), true);
 TreeViewer treeViewer = filteredTree.getViewer();

The above code works fine for a TreeViewer. Is there a similar way to attach such kind of a filter to a Nebula GridTreeViewer? If yes, please tell me. Would be very helpful. Thanks.

score 2 · Answer 1 · answered Nov 26 '13 at 11:32

You will have to create your own quick search adapter. Observe the code in FilteredTree.

I can't post my own adapter, since it's company property. Here are some hints.

Things you will need in your MyQuickSearchAdapter:

public QuickSearchAdapter(Composite parent) constructor
A setViewer(StructuredViewer) API that does this.viewer = viewer and this.viewer.addFilter(viewerFilter) (see below for viewerFilter)
An abstract method getLabelProvider() to access a viewer's LabelProvider (in our case, GridTreeViewer)
Creation methods for a Text field that will represent the quick search area.
(Optional) Creation method for a label/button that clears the text when clicked (as in FilteredTree) - although this is overkill, in my opinion.

private MyViewerFilter extends ViewerFilter nested class, that does the actual filtering. This will have a String instance field that holds the search text; this field will have a setter that will be called each time you type something in the filter box. Will look something like viewerFilter.setSearchText(filterBox.getText());. This nested class will also override the select(Viewer, Object, Object), which will use the getLabelProvider().getText(element) to extract the text for a certain cell. Something like:

// Automatically adds wildcard characters before and after search string:
public static final String QSEARCH_REGEX_PATTERN = "(.*)%s(.*)"; //$NON-NLS-1$

private class MyViewerFilter extends ViewerFilter 
{
    // --------------------- <Instance Fields> -----------------------

    private String searchString;

    // --------------------- <Setters> -----------------------

    /**
     * @param 
     *      Text that goes inside the REGEX pattern
     */
    public void setSearchText(final String searchString) 
    {
        //this.searchString = "(.*)" + searchString.toLowerCase() + "(.*)";  //$NON-NLS-1$ //$NON-NLS-2$
        this.searchString = String.format(QSEARCH_REGEX_PATTERN, searchString.toLowerCase());
    }

    // --------------------- <Overridden search method> -----------------------

    @Override
    public boolean select(final Viewer viewer, final Object parentElement, final Object element) 
    {
        if (StringUtils.isEmpty(searchString))
            return true;

        final String text = getLabelProvider().getText(element);

        if (StringUtils.isEmpty(text))
            return true;

        return text.toLowerCase().matches(searchString);
    }
}

That's the hard part. After that, you just make a class called MyFilteredGridTreeViewer, and add the quick search adapter along side the grid viewer. Also remember to call quickSearchAdapter.setViewer(gridViewer), and you're done!

Nebula GridTreeViewer - Is there a way to show the filter like FilteredTree in eclipse?

1 Answers1