Java tutorial
/* * This library is part of Geranium - * an open source UI library for GWT. * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com)- * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * For further information about Alkacon Software, please see the * company website: http://www.alkacon.com * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package com.alkacon.geranium.client.util; import com.alkacon.geranium.client.ui.css.I_LayoutBundle; import com.google.gwt.dom.client.Style.Unit; import com.google.gwt.event.dom.client.HasAllMouseHandlers; import com.google.gwt.event.dom.client.MouseMoveEvent; import com.google.gwt.event.dom.client.MouseMoveHandler; import com.google.gwt.event.dom.client.MouseOutEvent; import com.google.gwt.event.dom.client.MouseOutHandler; import com.google.gwt.event.dom.client.MouseOverEvent; import com.google.gwt.event.dom.client.MouseOverHandler; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Element; import com.google.gwt.user.client.Timer; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.RootPanel; /** * A tool-tip handler. Allowing to show any HTML as a tool-tip on mouse over.<p> */ public class ToolTipHandler implements MouseOverHandler, MouseMoveHandler, MouseOutHandler { /** The default tool-tip left offset. */ private static final int DEFAULT_OFFSET_LEFT = 10; /** The default tool-tip top offset. */ private static final int DEFAULT_OFFSET_TOP = 10; /** Time to wait before removing the tool tip. */ private static final int REMOVE_SCHEDULE = 10000; /** The mouse move handler registration. */ private HandlerRegistration m_moveHandlerRegistration; /** The tool-tip left offset. */ private int m_offsetLeft; /** The tool-tip top offset. */ private int m_offsetTop; /** The mouse out handler registration. */ private HandlerRegistration m_outHandlerRegistration; /** The mouse over handler registration. */ private HandlerRegistration m_overHandlerRegistration; /** Timer to remove the tool tip again. */ private Timer m_removeTimer; /** Flag indicating if the tool-tip is currently showing. */ private boolean m_showing; /** The widget to show the tool-tip for. */ private HasAllMouseHandlers m_target; /** The tool-tip element. */ private Element m_toolTip; /** The tool-tip HTML to show. */ private String m_toolTipHtml; /** * Constructor. Adds the tool-tip handler to the target.<p> * * @param target the target to show the tool-tip on * @param toolTipHtml the tool-tip content */ public ToolTipHandler(HasAllMouseHandlers target, String toolTipHtml) { m_target = target; m_toolTipHtml = toolTipHtml; m_offsetLeft = DEFAULT_OFFSET_LEFT; m_offsetTop = DEFAULT_OFFSET_TOP; m_overHandlerRegistration = m_target.addMouseOverHandler(this); } /** * Removes the tool-tip and mouse move and out handlers.<p> */ public void clearShowing() { m_showing = false; if (m_toolTip != null) { m_toolTip.removeFromParent(); m_toolTip = null; } if (m_moveHandlerRegistration != null) { m_moveHandlerRegistration.removeHandler(); m_moveHandlerRegistration = null; } if (m_outHandlerRegistration != null) { m_outHandlerRegistration.removeHandler(); m_outHandlerRegistration = null; } m_removeTimer = null; } /** * Returns the tool-tip HTML.<p> * * @return the tool-tip HTML */ public String getToolTipHtml() { return m_toolTipHtml; } /** * Returns if the tool-tip is showing.<p> * * @return <code>true</code> if the tool-tip is showing */ public boolean isShowing() { return m_showing; } /** * @see com.google.gwt.event.dom.client.MouseMoveHandler#onMouseMove(com.google.gwt.event.dom.client.MouseMoveEvent) */ public void onMouseMove(MouseMoveEvent event) { m_removeTimer.schedule(REMOVE_SCHEDULE); setToolTipPosition(event.getClientX(), event.getClientY()); } /** * @see com.google.gwt.event.dom.client.MouseOutHandler#onMouseOut(com.google.gwt.event.dom.client.MouseOutEvent) */ public void onMouseOut(MouseOutEvent event) { if (m_removeTimer != null) { m_removeTimer.cancel(); } clearShowing(); } /** * @see com.google.gwt.event.dom.client.MouseOverHandler#onMouseOver(com.google.gwt.event.dom.client.MouseOverEvent) */ public void onMouseOver(MouseOverEvent event) { // make sure not to double assign any handlers if (m_removeTimer != null) { m_removeTimer.cancel(); } clearShowing(); createTimer(); m_removeTimer.schedule(REMOVE_SCHEDULE); m_showing = true; m_moveHandlerRegistration = m_target.addMouseMoveHandler(this); m_outHandlerRegistration = m_target.addMouseOutHandler(this); if (m_toolTip == null) { m_toolTip = DOM.createDiv(); m_toolTip.addClassName(I_LayoutBundle.INSTANCE.generalCss().toolTip()); m_toolTip.addClassName(I_LayoutBundle.INSTANCE.generalCss().cornerAll()); } m_toolTip.setInnerHTML(m_toolTipHtml); RootPanel.getBodyElement().appendChild(m_toolTip); setToolTipPosition(event.getClientX(), event.getClientY()); } /** * Removes this tool-tip handler completely. This instance will not be reusable.<p> */ public void removeHandler() { clearShowing(); if (m_overHandlerRegistration != null) { m_overHandlerRegistration.removeHandler(); m_overHandlerRegistration = null; } m_target = null; } /** * Sets the tool-tip left offset.<p> * * @param offsetLeft the tool-tip left offset to set */ public void setOffsetLeft(int offsetLeft) { m_offsetLeft = offsetLeft; } /** * Sets the tool-tip top offset.<p> * * @param offsetTop the tool-tip top offset to set */ public void setOffsetTop(int offsetTop) { m_offsetTop = offsetTop; } /** * Sets the tool-tip HTML.<p> * * @param toolTipHtml the tool-tip HTML to set */ public void setToolTipHtml(String toolTipHtml) { m_toolTipHtml = toolTipHtml; if (m_showing) { m_toolTip.setInnerHTML(toolTipHtml); } } /** * Creates the remove tool tip timer.<p> */ private void createTimer() { m_removeTimer = new Timer() { /** * @see com.google.gwt.user.client.Timer#run() */ @Override public void run() { clearShowing(); } }; } /** * Sets the tool-tip position.<p> * * @param absLeft the mouse pointer absolute left * @param absTop the mouse pointer absolute top */ private void setToolTipPosition(int absLeft, int absTop) { if (m_toolTip != null) { int height = m_toolTip.getOffsetHeight(); int width = m_toolTip.getOffsetWidth(); int windowHeight = Window.getClientHeight(); int windowWidth = Window.getClientWidth(); int left = absLeft + m_offsetLeft; if ((left + width) > windowWidth) { left = windowWidth - m_offsetLeft - width; } m_toolTip.getStyle().setLeft(left, Unit.PX); int top = absTop + m_offsetTop; if (((top + height) > windowHeight) && ((height + m_offsetTop) < absTop)) { top = absTop - m_offsetTop - height; } m_toolTip.getStyle().setTop(top, Unit.PX); } } }