Java tutorial
/** * Copyright 2006 Google Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); you may not * use this file except in compliance with the License. You may obtain a copy of * the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations under * the License. */ package liber.edit.client; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.ui.ClickListener; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.HorizontalPanel; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.SourcesTabEvents; import com.google.gwt.user.client.ui.TabListener; import com.google.gwt.user.client.ui.TabListenerCollection; import com.google.gwt.user.client.ui.Widget; /** * A horizontal bar of folder-style tabs, most commonly used as part of a * {@link com.google.gwt.user.client.ui.TabPanel}. * * <p> * <img class='gallery' src='TabBar.png'/> * </p> * * <h3>CSS Style Rules</h3> * <ul class='css'> * <li>.gwt-TabBar { the tab bar itself }</li> * <li>.gwt-TabBar .gwt-TabBarFirst { the left edge of the bar }</li> * <li>.gwt-TabBar .gwt-TabBarRest { the right edge of the bar }</li> * <li>.gwt-TabBar .gwt-TabBarItem { unselected tabs }</li> * <li>.gwt-TabBar .gwt-TabBarItem-selected { additional style for selected tabs } </li> * </ul> * * <p> * <h3>Example</h3> {@example com.google.gwt.examples.TabBarExample} * </p> */ public class CustomTabBar extends Composite implements SourcesTabEvents, ClickListener { private HorizontalPanel panel = new HorizontalPanel(); private Widget selectedTab; private TabListenerCollection tabListeners; /** * Creates an empty tab bar. */ public CustomTabBar() { initWidget(panel); sinkEvents(Event.ONCLICK); setStyleName("gwt-TabBar"); panel.setVerticalAlignment(HorizontalPanel.ALIGN_BOTTOM); HTML first = new HTML(" ", true), rest = new HTML(" ", true); first.setStyleName("gwt-TabBarFirst"); rest.setStyleName("gwt-TabBarRest"); //first.setHeight("100%"); //rest.setHeight("100%"); panel.add(first); panel.add(rest); //first.setHeight("100%"); panel.setCellHeight(first, "100%"); panel.setCellWidth(rest, "100%"); } /** * Adds a new tab with the specified text. * * @param text the new tab's text */ public void addTab(String text) { insertTab(text, getTabCount()); } /** * Adds a new tab with the specified text. * * @param text the new tab's text * @param asHTML <code>true</code> to treat the specified text as html */ public void addTab(String text, boolean asHTML) { insertTab(text, asHTML, getTabCount()); } public void addTabListener(TabListener listener) { if (tabListeners == null) tabListeners = new TabListenerCollection(); tabListeners.add(listener); } /** * Gets the tab that is currently selected. * * @return the selected tab */ public int getSelectedTab() { if (selectedTab == null) return -1; return panel.getWidgetIndex(selectedTab) - 1; } /** * Gets the number of tabs present. * * @return the tab count */ public int getTabCount() { return panel.getWidgetCount() - 2; } /** * Gets the specified tab's HTML. * * @param index the index of the tab whose HTML is to be retrieved * @return the tab's HTML */ public String getTabHTML(int index) { if (index >= getTabCount()) return null; return ((HTML) panel.getWidget(index - 1)).getHTML(); } /** * Inserts a new tab at the specified index. * * @param text the new tab's text * @param asHTML <code>true</code> to treat the specified text as HTML * @param beforeIndex the index before which this tab will be inserted */ public void insertTab(String text, boolean asHTML, int beforeIndex) { if ((beforeIndex < 0) || (beforeIndex > getTabCount())) throw new IndexOutOfBoundsException(); Label item; if (asHTML) item = new HTML(text); else item = new Label(text); item.setWordWrap(false); item.addClickListener(this); item.setStyleName("gwt-TabBarItem"); panel.insert(item, beforeIndex + (beforeIndex + 1)); /** * TabBarSpacer mod * by spekkio <dummymael@gmail.com> */ HTML spacer = new HTML(" ", true); int spacerIndex = panel.getWidgetIndex(item); spacer.setStyleName("gwt-TabBarSpacer"); panel.insert(spacer, spacerIndex + 1); } /** * Inserts a new tab at the specified index. * * @param text the new tab's text * @param beforeIndex the index before which this tab will be inserted */ public void insertTab(String text, int beforeIndex) { insertTab(text, false, beforeIndex); } public void onClick(Widget sender) { for (int i = 1; i < panel.getWidgetCount() - 1; ++i) { if (panel.getWidget(i) == sender) { selectTab(i - 1); return; } } } /** * Removes the tab at the specified index. * * @param index the index of the tab to be removed */ public void removeTab(int index) { checkTabIndex(index); // (index + 1) to account for 'first' placeholder widget. Widget toRemove = panel.getWidget(index + 1); if (toRemove == selectedTab) selectedTab = null; panel.remove(toRemove); } public void removeTabListener(TabListener listener) { if (tabListeners != null) tabListeners.remove(listener); } /** * Programmatically selects the specified tab. * * @param index the index of the tab to be selected * @return <code>true</code> if successful, <code>false</code> if the * change is denied by the {@link TabListener}. */ public boolean selectTab(int index) { checkTabIndex(index); if (tabListeners != null) { // changed to (index/2) since each tab is now paired with a spacer if (!tabListeners.fireBeforeTabSelected(this, index / 2)) return false; } setSelectionStyle(selectedTab, false); selectedTab = panel.getWidget(index + 1); setSelectionStyle(selectedTab, true); if (tabListeners != null) // changed to (index/2) since each tab is now paired with a spacer tabListeners.fireTabSelected(this, index / 2); return true; } private void checkTabIndex(int index) { if ((index < 0) || (index >= getTabCount())) throw new IndexOutOfBoundsException(); } private void setSelectionStyle(Widget item, boolean selected) { if (item != null) { if (selected) item.setStyleName("gwt-TabBarItem-selected"); else item.setStyleName("gwt-TabBarItem"); } } }