Java tutorial
/* * SoftVerticalScroll.java * * Created on August 16, 2007, 12:21 PM * * 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. * * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ package com.totsp.gwittir.client.fx.ui; import com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Timer; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.WindowResizeListener; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.FocusPanel; import com.google.gwt.user.client.ui.MouseListener; import com.google.gwt.user.client.ui.MouseListenerAdapter; import com.google.gwt.user.client.ui.ScrollListener; import com.google.gwt.user.client.ui.SimplePanel; import com.google.gwt.user.client.ui.VerticalPanel; import com.google.gwt.user.client.ui.Widget; /** * * @author <a href="mailto:cooper@screaming-penguin.com">Robert "kebernet" Cooper</a> */ public class SoftScrollbar extends Composite { VerticalPanel vertical = new VerticalPanel(); FocusPanel barTarget = new FocusPanel(); FocusPanel higherTarget = new FocusPanel(); FocusPanel lowerTarget = new FocusPanel(); ScrollListener scrollListener = new ScrollListener() { public void onScroll(Widget widget, int scrollLeft, int scrollTop) { refresh(); } }; SimplePanel bar = new SimplePanel(); SimplePanel base; SimplePanel higher = new SimplePanel(); SimplePanel lower = new SimplePanel(); SoftScrollArea target; private MouseListener barListener = new MouseListenerAdapter() { boolean inDrag = false; int start; public void onMouseLeave(Widget sender) { inDrag = false; } public void onMouseUp(Widget sender, int x, int y) { inDrag = false; } public void onMouseDown(Widget sender, int x, int y) { inDrag = true; start = y; } public void onMouseMove(Widget sender, int x, int y) { if (inDrag) { float newPercent = (float) ((y - start) + lower.getOffsetHeight()) / (float) base.getOffsetHeight(); int newPosition = Math .round((target.getOffsetHeight() + target.getMaxScrollPosition()) * newPercent) + x; target.setScrollPosition(newPosition); } } }; private MouseListener higherListener = new MouseListenerAdapter() { public void onMouseDown(Widget sender, int x, int y) { float newPercent = (float) (y + lower.getOffsetHeight() + bar.getOffsetHeight()) / (float) base.getOffsetHeight(); int newPosition = Math.round((target.getOffsetHeight() + target.getMaxScrollPosition()) * newPercent) - (target.getOffsetHeight() / 2); target.setScrollPosition(newPosition); } }; private MouseListener lowerListener = new MouseListenerAdapter() { public void onMouseDown(Widget sender, int x, int y) { float newPercent = (float) y / (float) base.getOffsetHeight(); int newPosition = Math.round((target.getOffsetHeight() + target.getMaxScrollPosition()) * newPercent) - (target.getOffsetHeight() / 2); target.setScrollPosition(newPosition); } }; private WindowResizeListener windowListener = new WindowResizeListener() { public void onWindowResized(int width, int height) { refresh(); } }; /** Creates a new instance of SoftVerticalScroll */ public SoftScrollbar(SoftScrollArea target) { this.target = target; this.base = new SimplePanel(); this.base.setWidget(vertical); super.initWidget(this.base); this.higherTarget.setWidget(this.higher); this.barTarget.setWidget(this.bar); this.lowerTarget.setWidget(this.lower); vertical.add(lowerTarget); vertical.add(barTarget); vertical.add(higherTarget); this.setStyleName("gwittir-SoftScrollbar"); this.bar.setStyleName("bar"); this.lower.setStyleName("lower"); this.higher.setStyleName("higher"); DOM.setStyleAttribute(this.lower.getElement(), "overflow", "hidden"); DOM.setStyleAttribute(this.bar.getElement(), "overflow", "hidden"); DOM.setStyleAttribute(this.higher.getElement(), "overflow", "hidden"); DOM.setStyleAttribute(this.lowerTarget.getElement(), "overflow", "hidden"); DOM.setStyleAttribute(this.barTarget.getElement(), "overflow", "hidden"); DOM.setStyleAttribute(this.higherTarget.getElement(), "overflow", "hidden"); DOM.setStyleAttribute(this.getElement(), "overflow", "hidden"); } protected MouseListener getBarListener() { return barListener; } protected MouseListener getHigherListener() { return this.higherListener; } protected MouseListener getLowerListener() { return this.lowerListener; } protected void onAttach() { super.onAttach(); target.addScrollListener(this.scrollListener); this.lowerTarget.addMouseListener(this.getLowerListener()); this.higherTarget.addMouseListener(this.getHigherListener()); this.barTarget.addMouseListener(this.getBarListener()); Window.addWindowResizeListener(this.windowListener); Timer t = new Timer() { public void run() { refresh(); } }; t.schedule(10); } protected void onDetach() { super.onDetach(); Window.removeWindowResizeListener(this.windowListener); target.removeScrollListener(this.scrollListener); this.lowerTarget.removeMouseListener(this.getLowerListener()); this.higherTarget.removeMouseListener(this.getHigherListener()); this.barTarget.removeMouseListener(this.getBarListener()); } public void refresh() { int currentHeight = this.getOffsetHeight(); float pageSize = (float) target.getOffsetHeight() / (float) (target.getMaxScrollPosition() + target.getOffsetHeight()); //GWT.log("Page sisze " + pageSize, null); float scrollPercentage = (float) target.getScrollPosition() / (target.getMaxScrollPosition() + 1); int lowerHeight = Math .round((currentHeight - Math.round((float) currentHeight * pageSize)) * scrollPercentage); lowerHeight = lowerHeight == 0 ? 1 : lowerHeight; // Fixes MSIE; this.lower.setHeight(lowerHeight + "px"); int barHeight = Math.round(currentHeight * pageSize); this.bar.setHeight(barHeight + "px"); int higherHeight = currentHeight - lowerHeight - barHeight; higherHeight = higherHeight < 0 ? 0 : higherHeight; this.higher.setHeight(higherHeight + "px"); if (this.getOffsetWidth() >= 0) { this.lower.setWidth(this.getOffsetWidth() + "px"); this.bar.setWidth(this.getOffsetWidth() + "px"); this.higher.setWidth(this.getOffsetWidth() + "px"); } } public void setBarWidget(Widget w) { this.bar.setWidget(w); DOM.setStyleAttribute(this.bar.getElement(), "overflow", "hidden"); } public void setHigherWidget(Widget w) { this.higher.setWidget(w); DOM.setStyleAttribute(this.higher.getElement(), "overflow", "hidden"); } public void setLowerWidget(Widget w) { this.lower.setWidget(w); DOM.setStyleAttribute(this.lower.getElement(), "overflow", "hidden"); } }