vaadin-framework/src/com/itmill/toolkit/terminal/gwt/client/ui/ITabsheetPanel.java

package com.itmill.toolkit.terminal.gwt.client.ui;

import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.ui.ComplexPanel;
import com.google.gwt.user.client.ui.Widget;

/**
 * A panel that displays all of its child widgets in a 'deck', where only one
 * can be visible at a time. It is used by
 * {@link com.itmill.toolkit.terminal.gwt.client.ui.ITabsheetPanel}.
 * 
 * This class has the same basic functionality as the GWT DeckPanel
 * {@link com.google.gwt.user.client.ui.DeckPanel}, with the exception that it
 * doesn't manipulate the child widgets' width and height attributes.
 */
public class ITabsheetPanel extends ComplexPanel {

	private Widget visibleWidget;

	/**
	 * Creates an empty tabsheet panel.
	 */
	public ITabsheetPanel() {
		setElement(DOM.createDiv());
	}

	/**
	 * Adds the specified widget to the deck.
	 * 
	 * @param w
	 *            the widget to be added
	 */
	public void add(Widget w) {
		super.add(w, getElement());
		initChildWidget(w);
	}

	/**
	 * Gets the index of the currently-visible widget.
	 * 
	 * @return the visible widget's index
	 */
	public int getVisibleWidget() {
		return getWidgetIndex(visibleWidget);
	}

	/**
	 * Inserts a widget before the specified index.
	 * 
	 * @param w
	 *            the widget to be inserted
	 * @param beforeIndex
	 *            the index before which it will be inserted
	 * @throws IndexOutOfBoundsException
	 *             if <code>beforeIndex</code> is out of range
	 */
	public void insert(Widget w, int beforeIndex) {
		super.insert(w, getElement(), beforeIndex, true);
		initChildWidget(w);
	}

	public boolean remove(Widget w) {
		boolean removed = super.remove(w);
		if (removed) {
			resetChildWidget(w);

			if (visibleWidget == w) {
				visibleWidget = null;
			}
		}
		return removed;
	}

	/**
	 * Shows the widget at the specified index. This causes the currently-
	 * visible widget to be hidden.
	 * 
	 * @param index
	 *            the index of the widget to be shown
	 */
	public void showWidget(int index) {
		checkIndexBoundsForAccess(index);

		if (visibleWidget != null) {
			visibleWidget.setVisible(false);
		}
		visibleWidget = getWidget(index);
		visibleWidget.setVisible(true);
	}

	/**
	 * Make the widget invisible, and set its width and height to full.
	 */
	private void initChildWidget(Widget w) {
		w.setVisible(false);
	}

	/**
	 * Make the widget visible, and clear the widget's width and height
	 * attributes. This is done so that any changes to the visibility, height,
	 * or width of the widget that were done by the panel are undone.
	 */
	private void resetChildWidget(Widget w) {
		w.setVisible(true);
	}
}