XViewerListCellEditor.java

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 * This file is protected by Copyright.
 * Please refer to the COPYRIGHT file distributed with this source distribution.
 *
 * This file is part of REDHAWK IDE.
 *
 * All rights reserved.  This program and the accompanying materials are made available under
 * the terms of the Eclipse Public License v1.0 which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *******************************************************************************/
package gov.redhawk.ide.sad.internal.ui.editor;

import java.util.ArrayList;
import java.util.Collection;

import org.eclipse.jface.viewers.ILabelProvider;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.events.SelectionListener;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.ScrollBar;
import org.eclipse.swt.widgets.Shell;

public class XViewerListCellEditor extends XViewerCellEditor {

	private Shell popup = null;
	private List list = null;
	private java.util.List<Object> items;
	private SelectionListener selectionListener;
	private Object value = null;
	private ILabelProvider labelProvider = null;

	public XViewerListCellEditor(Composite parent, Collection< ? > items) {
		super(parent);
		this.items = new ArrayList<Object>(items);
		setValueValid(true);
	}

	@Override
	public void dispose() {
		popup.dispose();
		super.dispose();
	}

	@Override
	public boolean setFocus() {
		if (popup == null) {
			createPopup(getParent());
		}

		// Determine the bounds of the list--since it is going to pop over the cell, we can use whatever size we want.
		// Use the width of the cell, but for height try to determine how large it should be to show a reasonable
		// number of items (logic borrowed from SWT's CCombo).
		int itemHeight = list.getItemHeight();
		int maxHeight = getMonitor().getClientArea().height / 3;
		int visibleItemCount = Math.max(5, maxHeight / itemHeight);
		int itemCount = Math.min(list.getItemCount(), visibleItemCount);
		Point listSize = list.computeSize(SWT.DEFAULT, itemCount * itemHeight, false);
		int width = getSize().x;
		int height = listSize.y;
		// Also borrowed from CCombo: if the horizontal scroll bar isn't shown, offset the size so as not to waste
		// vertical real estate
		ScrollBar hBar = list.getHorizontalBar();
		if (!hBar.isVisible()) {
			height -= hBar.getSize().y;
		}

		// Pop up the Shell directly on top of the cell, sized to exactly match our computed list size
		Display display = getDisplay();
		Point position = display.map(getParent(), null, getLocation());
		popup.setBounds(position.x, position.y, width, height);
		list.setBounds(0, 0, width, height);
		popup.setVisible(true);
		return list.setFocus();
	}

	public void setLabelProvider(ILabelProvider labelProvider) {
		this.labelProvider = labelProvider;
	}

	@Override
	protected void doSetValue(Object value) {
		this.value = value;
		if (list != null) {
			list.removeSelectionListener(selectionListener);
			if (value != null) {
				list.setSelection(new String[] { (String) value });
			} else {
				list.setSelection(0);
			}
			list.addSelectionListener(selectionListener);
		}
	}

	@Override
	protected Object doGetValue() {
		int index = list.getSelectionIndex();
		if (index >= 0) {
			return items.get(index);
		} else {
			return null;
		}
	}

	protected void createPopup(Control parent) {
		popup = new Shell(getShell(), SWT.NO_TRIM | SWT.ON_TOP);
		list = new List(popup, SWT.BORDER | SWT.SINGLE | SWT.H_SCROLL | SWT.V_SCROLL);
		list.setBackground(parent.getBackground());
		list.setForeground(parent.getForeground());
		list.setFont(parent.getFont());

		list.setItems(getListItems());
		int index = Math.max(0, items.indexOf(value));
		list.setSelection(index);

		selectionListener = new SelectionListener() {

			@Override
			public void widgetSelected(SelectionEvent e) {
			}

			@Override
			public void widgetDefaultSelected(SelectionEvent e) {
				deactivate();
			}
		};
		list.addSelectionListener(selectionListener);

		list.addMouseListener(new MouseAdapter() {

			@Override
			public void mouseUp(MouseEvent e) {
				deactivate();
			}

		});

		forwardEvents(SWT.FocusOut, list, true);
		forwardEvents(SWT.Traverse, list, true);
	}

	protected String[] getListItems() {
		ArrayList<String> stringItems = new ArrayList<String>(items.size());
		for (Object item : items) {
			String label = getText(item);
			stringItems.add(label);
		}
		return stringItems.toArray(new String[stringItems.size()]);
	}

	protected String getText(Object object) {
		if (labelProvider != null) {
			return labelProvider.getText(object);
		} else if (object != null) {
			return object.toString();
		} else {
			return "";
		}
	}
}