org.eclipse.jface.viewers.TreeViewerFocusCellManager.java Source code

Introduction

Here is the source code for org.eclipse.jface.viewers.TreeViewerFocusCellManager.java

Source

/*******************************************************************************
 * Copyright (c) 2007, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Tom Schindl<tom.schindl@bestsolution.at> - initial API and implementation
 *                                      - fix in bug: 195908, 210752
 *******************************************************************************/

package org.eclipse.jface.viewers;

import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Item;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

/**
 * This class is responsible to provide the concept of cells for {@link Tree}.
 * This concept is needed to provide features like editor activation with the
 * keyboard
 *
 * @since 3.3
 *
 */
public class TreeViewerFocusCellManager extends SWTFocusCellManager {
    private static final CellNavigationStrategy TREE_NAVIGATE = new CellNavigationStrategy() {
        @Override
        public void collapse(ColumnViewer viewer, ViewerCell cellToCollapse, Event event) {
            if (cellToCollapse != null) {
                ((TreeItem) cellToCollapse.getItem()).setExpanded(false);
            }
        }

        @Override
        public void expand(ColumnViewer viewer, ViewerCell cellToExpand, Event event) {
            if (cellToExpand != null) {
                TreeViewer v = (TreeViewer) viewer;
                v.setExpandedState(v.getTreePathFromItem((Item) cellToExpand.getItem()), true);
            }
        }

        @Override
        public boolean isCollapseEvent(ColumnViewer viewer, ViewerCell cellToCollapse, Event event) {

            return cellToCollapse != null && ((TreeItem) cellToCollapse.getItem()).getExpanded()
                    && event.keyCode == SWT.ARROW_LEFT && isFirstColumnCell(cellToCollapse);
        }

        @Override
        public boolean isExpandEvent(ColumnViewer viewer, ViewerCell cellToExpand, Event event) {

            return cellToExpand != null && ((TreeItem) cellToExpand.getItem()).getItemCount() > 0
                    && !((TreeItem) cellToExpand.getItem()).getExpanded() && event.keyCode == SWT.ARROW_RIGHT
                    && isFirstColumnCell(cellToExpand);
        }

        private boolean isFirstColumnCell(ViewerCell cell) {
            return cell.getViewerRow().getVisualIndex(cell.getColumnIndex()) == 0;
        }
    };

    /**
     * Create a new manager using a default navigation strategy:
     * <ul>
     * <li><code>SWT.ARROW_UP</code>: navigate to cell above</li>
     * <li><code>SWT.ARROW_DOWN</code>: navigate to cell below</li>
     * <li><code>SWT.ARROW_RIGHT</code>: on first column (collapses if item
     * is expanded) else navigate to next visible cell on the right</li>
     * <li><code>SWT.ARROW_LEFT</code>: on first column (expands if item is
     * collapsed) else navigate to next visible cell on the left</li>
     * </ul>
     *
     * @param viewer
     *            the viewer the manager is bound to
     * @param focusDrawingDelegate
     *            the delegate responsible to highlight selected cell
     */
    public TreeViewerFocusCellManager(TreeViewer viewer, FocusCellHighlighter focusDrawingDelegate) {
        this(viewer, focusDrawingDelegate, TREE_NAVIGATE);
    }

    /**
     * Create a new manager with a custom navigation strategy
     *
     * @param viewer
     *            the viewer the manager is bound to
     * @param focusDrawingDelegate
     *            the delegate responsible to highlight selected cell
     * @param navigationStrategy
     *            the strategy used to navigate the cells
     * @since 3.4
     */
    public TreeViewerFocusCellManager(TreeViewer viewer, FocusCellHighlighter focusDrawingDelegate,
            CellNavigationStrategy navigationStrategy) {
        super(viewer, focusDrawingDelegate, navigationStrategy);
    }

    @Override
    ViewerCell getInitialFocusCell() {
        Tree tree = (Tree) getViewer().getControl();

        if (!tree.isDisposed() && tree.getItemCount() > 0 && !tree.getTopItem().isDisposed()) {
            ViewerRow aViewerRow = getViewer().getViewerRowFromItem(tree.getTopItem());
            if (tree.getColumnCount() == 0) {
                return aViewerRow.getCell(0);
            }

            Rectangle clientArea = tree.getClientArea();
            for (int i = 0; i < tree.getColumnCount(); i++) {
                if (aViewerRow.getWidth(i) > 0 && columnInVisibleArea(clientArea, aViewerRow, i))
                    return aViewerRow.getCell(i);
            }
        }

        return null;
    }

    private boolean columnInVisibleArea(Rectangle clientArea, ViewerRow row, int colIndex) {
        return row.getBounds(colIndex).x >= clientArea.x;
    }

    @Override
    public ViewerCell getFocusCell() {
        ViewerCell cell = super.getFocusCell();
        Tree t = (Tree) getViewer().getControl();

        // It is possible that the selection has changed under the hood
        if (cell != null) {
            if (t.getSelection().length == 1 && t.getSelection()[0] != cell.getItem()) {
                setFocusCell(getViewer().getViewerRowFromItem(t.getSelection()[0]).getCell(cell.getColumnIndex()));
            }
        }

        return super.getFocusCell();
    }
}