Java tutorial
/* * Copyright 2008 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 com.google.gwt.user.client.ui; import com.google.gwt.event.logical.shared.BeforeSelectionEvent; import com.google.gwt.event.logical.shared.BeforeSelectionHandler; import com.google.gwt.event.logical.shared.HasBeforeSelectionHandlers; import com.google.gwt.event.logical.shared.HasSelectionHandlers; import com.google.gwt.event.logical.shared.SelectionEvent; import com.google.gwt.event.logical.shared.SelectionHandler; import com.google.gwt.event.shared.HandlerRegistration; import java.util.Iterator; /** * A panel that represents a tabbed set of pages, each of which contains another * widget. Its child widgets are shown as the user selects the various tabs * associated with them. The tabs can contain arbitrary HTML. * * <p> * This widget will <em>only</em> work in quirks mode. If your application is in * Standards Mode, use {@link TabLayoutPanel} instead. * </p> * * <p> * <img class='gallery' src='doc-files/TabPanel.png'/> * </p> * * <p> * Note that this widget is not a panel per se, but rather a * {@link com.google.gwt.user.client.ui.Composite} that aggregates a * {@link com.google.gwt.user.client.ui.TabBar} and a * {@link com.google.gwt.user.client.ui.DeckPanel}. It does, however, implement * {@link com.google.gwt.user.client.ui.HasWidgets}. * </p> * * <h3>CSS Style Rules</h3> * <ul class='css'> * <li>.gwt-TabPanel { the tab panel itself }</li> * <li>.gwt-TabPanelBottom { the bottom section of the tab panel * (the deck containing the widget) }</li> * </ul> * * <p> * <h3>Example</h3> * {@example com.google.gwt.examples.TabPanelExample} * </p> * * @see TabLayoutPanel */ // Cannot do anything about tab panel implementing TabListener until next // release @SuppressWarnings("deprecation") public class TabPanel extends Composite implements TabListener, SourcesTabEvents, HasWidgets, HasAnimation, IndexedPanel.ForIsWidget, HasBeforeSelectionHandlers<Integer>, HasSelectionHandlers<Integer> { /** * This extension of DeckPanel overrides the public mutator methods to prevent * external callers from adding to the state of the DeckPanel. * <p> * Removal of Widgets is supported so that WidgetCollection.WidgetIterator * operates as expected. * </p> * <p> * We ensure that the DeckPanel cannot become of of sync with its associated * TabBar by delegating all mutations to the TabBar to this implementation of * DeckPanel. * </p> */ private static class TabbedDeckPanel extends DeckPanel { private final UnmodifiableTabBar tabBar; public TabbedDeckPanel(UnmodifiableTabBar tabBar) { this.tabBar = tabBar; } @Override public void add(Widget w) { throw new UnsupportedOperationException("Use TabPanel.add() to alter the DeckPanel"); } @Override public void clear() { throw new UnsupportedOperationException("Use TabPanel.clear() to alter the DeckPanel"); } @Override public void insert(Widget w, int beforeIndex) { throw new UnsupportedOperationException("Use TabPanel.insert() to alter the DeckPanel"); } @Override public boolean remove(Widget w) { // Removal of items from the TabBar is delegated to the DeckPanel // to ensure consistency int idx = getWidgetIndex(w); if (idx != -1) { tabBar.removeTabProtected(idx); return super.remove(w); } return false; } protected void insertProtected(Widget w, String tabText, boolean asHTML, int beforeIndex) { // Check to see if the TabPanel already contains the Widget. If so, // remove it and see if we need to shift the position to the left. int idx = getWidgetIndex(w); if (idx != -1) { remove(w); if (idx < beforeIndex) { beforeIndex--; } } tabBar.insertTabProtected(tabText, asHTML, beforeIndex); super.insert(w, beforeIndex); } protected void insertProtected(Widget w, Widget tabWidget, int beforeIndex) { // Check to see if the TabPanel already contains the Widget. If so, // remove it and see if we need to shift the position to the left. int idx = getWidgetIndex(w); if (idx != -1) { remove(w); if (idx < beforeIndex) { beforeIndex--; } } tabBar.insertTabProtected(tabWidget, beforeIndex); super.insert(w, beforeIndex); } } /** * This extension of TabPanel overrides the public mutator methods to prevent * external callers from modifying the state of the TabBar. */ private class UnmodifiableTabBar extends TabBar { @Override public void insertTab(String text, boolean asHTML, int beforeIndex) { throw new UnsupportedOperationException("Use TabPanel.insert() to alter the TabBar"); } @Override public void insertTab(Widget widget, int beforeIndex) { throw new UnsupportedOperationException("Use TabPanel.insert() to alter the TabBar"); } public void insertTabProtected(String text, boolean asHTML, int beforeIndex) { super.insertTab(text, asHTML, beforeIndex); } public void insertTabProtected(Widget widget, int beforeIndex) { super.insertTab(widget, beforeIndex); } @Override public void removeTab(int index) { // It's possible for removeTab() to function correctly, but it's // preferable to have only TabbedDeckPanel.remove() be operable, // especially since TabBar does not export an Iterator over its values. throw new UnsupportedOperationException("Use TabPanel.remove() to alter the TabBar"); } public void removeTabProtected(int index) { super.removeTab(index); } @Override protected SimplePanel createTabTextWrapper() { return TabPanel.this.createTabTextWrapper(); } } private final UnmodifiableTabBar tabBar = new UnmodifiableTabBar(); private final TabbedDeckPanel deck = new TabbedDeckPanel(tabBar); /** * Creates an empty tab panel. */ public TabPanel() { VerticalPanel panel = new VerticalPanel(); panel.add(tabBar); panel.add(deck); panel.setCellHeight(deck, "100%"); tabBar.setWidth("100%"); tabBar.addTabListener(this); initWidget(panel); setStyleName("gwt-TabPanel"); deck.setStyleName("gwt-TabPanelBottom"); // Add a11y role "tabpanel" Accessibility.setRole(deck.getElement(), Accessibility.ROLE_TABPANEL); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public void add(IsWidget w, IsWidget tabWidget) { add(asWidgetOrNull(w), asWidgetOrNull(tabWidget)); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public void add(IsWidget w, String tabText) { add(asWidgetOrNull(w), tabText); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public void add(IsWidget w, String tabText, boolean asHTML) { add(asWidgetOrNull(w), tabText, asHTML); } public void add(Widget w) { throw new UnsupportedOperationException("A tabText parameter must be specified with add()."); } /** * Adds a widget to the tab panel. If the Widget is already attached to the * TabPanel, it will be moved to the right-most index. * * @param w the widget to be added * @param tabText the text to be shown on its tab */ public void add(Widget w, String tabText) { insert(w, tabText, getWidgetCount()); } /** * Adds a widget to the tab panel. If the Widget is already attached to the * TabPanel, it will be moved to the right-most index. * * @param w the widget to be added * @param tabText the text to be shown on its tab * @param asHTML <code>true</code> to treat the specified text as HTML */ public void add(Widget w, String tabText, boolean asHTML) { insert(w, tabText, asHTML, getWidgetCount()); } /** * Adds a widget to the tab panel. If the Widget is already attached to the * TabPanel, it will be moved to the right-most index. * * @param w the widget to be added * @param tabWidget the widget to be shown in the tab */ public void add(Widget w, Widget tabWidget) { insert(w, tabWidget, getWidgetCount()); } public HandlerRegistration addBeforeSelectionHandler(BeforeSelectionHandler<Integer> handler) { return addHandler(handler, BeforeSelectionEvent.getType()); } public HandlerRegistration addSelectionHandler(SelectionHandler<Integer> handler) { return addHandler(handler, SelectionEvent.getType()); } /** * @deprecated Use {@link #addBeforeSelectionHandler} and {@link * #addSelectionHandler} instead */ @Deprecated public void addTabListener(TabListener listener) { ListenerWrapper.WrappedTabListener.add(this, listener); } public void clear() { while (getWidgetCount() > 0) { remove(getWidget(0)); } } /** * Gets the deck panel within this tab panel. Adding or removing Widgets from * the DeckPanel is not supported and will throw * UnsupportedOperationExceptions. * * @return the deck panel */ public DeckPanel getDeckPanel() { return deck; } /** * Gets the tab bar within this tab panel. Adding or removing tabs from from * the TabBar is not supported and will throw UnsupportedOperationExceptions. * * @return the tab bar */ public TabBar getTabBar() { return tabBar; } public Widget getWidget(int index) { return deck.getWidget(index); } public int getWidgetCount() { return deck.getWidgetCount(); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public int getWidgetIndex(IsWidget child) { return getWidgetIndex(asWidgetOrNull(child)); } public int getWidgetIndex(Widget widget) { return deck.getWidgetIndex(widget); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public void insert(IsWidget widget, IsWidget tabWidget, int beforeIndex) { insert(asWidgetOrNull(widget), asWidgetOrNull(tabWidget), beforeIndex); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public void insert(IsWidget widget, String tabText, boolean asHTML, int beforeIndex) { insert(asWidgetOrNull(widget), tabText, asHTML, beforeIndex); } /** * Convenience overload to allow {@link IsWidget} to be used directly. */ public void insert(IsWidget widget, String tabText, int beforeIndex) { insert(asWidgetOrNull(widget), tabText, beforeIndex); } /** * Inserts a widget into the tab panel. If the Widget is already attached to * the TabPanel, it will be moved to the requested index. * * @param widget the widget to be inserted * @param tabText the text to be shown on its tab * @param asHTML <code>true</code> to treat the specified text as HTML * @param beforeIndex the index before which it will be inserted */ public void insert(Widget widget, String tabText, boolean asHTML, int beforeIndex) { // Delegate updates to the TabBar to our DeckPanel implementation deck.insertProtected(widget, tabText, asHTML, beforeIndex); } /** * Inserts a widget into the tab panel. If the Widget is already attached to * the TabPanel, it will be moved to the requested index. * * @param widget the widget to be inserted * @param tabText the text to be shown on its tab * @param beforeIndex the index before which it will be inserted */ public void insert(Widget widget, String tabText, int beforeIndex) { insert(widget, tabText, false, beforeIndex); } /** * Inserts a widget into the tab panel. If the Widget is already attached to * the TabPanel, it will be moved to the requested index. * * @param widget the widget to be inserted. * @param tabWidget the widget to be shown on its tab. * @param beforeIndex the index before which it will be inserted. */ public void insert(Widget widget, Widget tabWidget, int beforeIndex) { // Delegate updates to the TabBar to our DeckPanel implementation deck.insertProtected(widget, tabWidget, beforeIndex); } public boolean isAnimationEnabled() { return deck.isAnimationEnabled(); } public Iterator<Widget> iterator() { // The Iterator returned by DeckPanel supports removal and will invoke // TabbedDeckPanel.remove(), which is an active function. return deck.iterator(); } /** * @deprecated Use {@link BeforeSelectionHandler#onBeforeSelection} instead */ @Deprecated public boolean onBeforeTabSelected(SourcesTabEvents sender, int tabIndex) { BeforeSelectionEvent<Integer> event = BeforeSelectionEvent.fire(this, tabIndex); return event == null || !event.isCanceled(); } /** * @deprecated Use {@link SelectionHandler#onSelection} instead */ @Deprecated public void onTabSelected(SourcesTabEvents sender, int tabIndex) { deck.showWidget(tabIndex); SelectionEvent.fire(this, tabIndex); } public boolean remove(int index) { // Delegate updates to the TabBar to our DeckPanel implementation return deck.remove(index); } /** * Removes the given widget, and its associated tab. * * @param widget the widget to be removed */ public boolean remove(Widget widget) { // Delegate updates to the TabBar to our DeckPanel implementation return deck.remove(widget); } /** * @deprecated Use the {@link HandlerRegistration#removeHandler} * method on the object returned by and add*Handler method instead */ @Deprecated public void removeTabListener(TabListener listener) { ListenerWrapper.WrappedTabListener.remove(this, listener); } /** * Programmatically selects the specified tab and fires events. * * @param index the index of the tab to be selected */ public void selectTab(int index) { selectTab(index, true); } /** * Programmatically selects the specified tab. * * @param index the index of the tab to be selected * @param fireEvents true to fire events, false not to */ public void selectTab(int index, boolean fireEvents) { tabBar.selectTab(index, fireEvents); } public void setAnimationEnabled(boolean enable) { deck.setAnimationEnabled(enable); } /** * Create a {@link SimplePanel} that will wrap the contents in a tab. * Subclasses can use this method to wrap tabs in decorator panels. * * @return a {@link SimplePanel} to wrap the tab contents, or null to leave * tabs unwrapped */ protected SimplePanel createTabTextWrapper() { return null; } /** * <b>Affected Elements:</b> * <ul> * <li>-bar = The tab bar.</li> * <li>-bar-tab# = The element containing the content of the tab itself.</li> * <li>-bar-tab-wrapper# = The cell containing the tab at the index.</li> * <li>-bottom = The panel beneath the tab bar.</li> * </ul> * * @see UIObject#onEnsureDebugId(String) */ @Override protected void onEnsureDebugId(String baseID) { super.onEnsureDebugId(baseID); tabBar.ensureDebugId(baseID + "-bar"); deck.ensureDebugId(baseID + "-bottom"); } }