Java tutorial
/* * Copyright 2011 cruxframework.org. * * 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 org.cruxframework.crux.widgets.client.rollingtabs; import org.cruxframework.crux.widgets.client.rollingpanel.CustomRollingPanel; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.dom.client.HasAllKeyHandlers; import com.google.gwt.event.dom.client.HasClickHandlers; import com.google.gwt.event.dom.client.KeyCodes; import com.google.gwt.event.dom.client.KeyDownEvent; import com.google.gwt.event.dom.client.KeyDownHandler; import com.google.gwt.event.dom.client.KeyPressEvent; import com.google.gwt.event.dom.client.KeyPressHandler; import com.google.gwt.event.dom.client.KeyUpEvent; import com.google.gwt.event.dom.client.KeyUpHandler; 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 com.google.gwt.user.client.DOM; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.ui.Accessibility; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.HasVerticalAlignment; import com.google.gwt.user.client.ui.HasWordWrap; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.SimplePanel; import com.google.gwt.user.client.ui.TabBar; import com.google.gwt.user.client.ui.UIObject; import com.google.gwt.user.client.ui.Widget; /** * Modified version of GWT TabBar that uses a CustomRollingPanel wrapping its Tabs. * * @author Thiago da Rosa de Bustamante - * * */ //TODO refatorar esta classe. Fazer sem tables public class RollingTabBar extends Composite implements HasBeforeSelectionHandlers<Integer>, HasSelectionHandlers<Integer> { private static final String STYLENAME_DEFAULT = "crux-TabBarItem"; private CustomRollingPanel panel; private Widget selectedTab; /** * Creates an empty tab bar. */ RollingTabBar() { panel = new CustomRollingPanel(); initWidget(panel); sinkEvents(Event.ONCLICK); setStyleName("crux-TabBar"); panel.setSpacing(0); panel.setScrollToAddedWidgets(true); // Add a11y role "tablist" Accessibility.setRole(panel.getElement(), Accessibility.ROLE_TABLIST); panel.setVerticalAlignment(HasVerticalAlignment.ALIGN_BOTTOM); HTML first = new HTML(" ", true), rest = new HTML(" ", true); first.setStyleName("crux-TabBarFirst"); rest.setStyleName("crux-TabBarRest"); first.setHeight("100%"); rest.setHeight("100%"); panel.add(first); panel.add(rest); first.setHeight("100%"); panel.setCellHeight(first, "100%"); panel.setCellWidth(rest, "100%"); setStyleName(first.getElement().getParentElement(), "crux-TabBarFirst-wrapper"); setStyleName(rest.getElement().getParentElement(), "crux-TabBarRest-wrapper"); } /** * @see com.google.gwt.event.logical.shared.HasBeforeSelectionHandlers#addBeforeSelectionHandler(com.google.gwt.event.logical.shared.BeforeSelectionHandler) */ public HandlerRegistration addBeforeSelectionHandler(BeforeSelectionHandler<Integer> handler) { return addHandler(handler, BeforeSelectionEvent.getType()); } /** * @see com.google.gwt.event.logical.shared.HasSelectionHandlers#addSelectionHandler(com.google.gwt.event.logical.shared.SelectionHandler) */ public HandlerRegistration addSelectionHandler(SelectionHandler<Integer> handler) { return addHandler(handler, SelectionEvent.getType()); } /** * 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; } /** * Enable or disable a tab. When disabled, users cannot select the tab. * * @param index the index of the tab to enable or disable * @param enabled true to enable, false to disable */ public void setTabEnabled(int index, boolean enabled) { assert (index >= 0) && (index < getTabCount()) : "Flap index out of bounds"; // Style the wrapper ClickDelegatePanel delPanel = (ClickDelegatePanel) panel.getWidget(index + 1); delPanel.setEnabled(enabled); setStyleName(delPanel.getElement(), "crux-TabBarItem-disabled", !enabled); setStyleName(delPanel.getElement().getParentElement(), "crux-TabBarItem-wrapper-disabled", !enabled); } /** * Gets the given tab. * * This method is final because the Flap interface will expand. Therefore * it is highly likely that subclasses which implemented this method would end up * breaking. * * @param index the tab's index * @return the tab wrapper */ public final Tab getTab(int index) { if (index >= getTabCount()) { return null; } ClickDelegatePanel p = (ClickDelegatePanel) panel.getWidget(index + 1); return p; } /** * Inserts a new tab at the specified index. * * @param widget * widget to be used in the new tab * @param beforeIndex * the index before which this tab will be inserted */ public void insertTab(Widget widget, int beforeIndex) { insertTabWidget(widget, beforeIndex); } /** * 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) { checkInsertBeforeTabIndex(beforeIndex); Label item; if (asHTML) { item = new HTML(text); } else { item = new Label(text); } item.setStyleName("flapLabel"); item.setWordWrap(false); SimpleDecoratedPanel panel = new SimpleDecoratedPanel(); panel.setContentWidget(item); insertTabWidget(panel, beforeIndex); } /** * Programmatically selects the specified tab. Use index -1 to specify that * no tab should be selected. * * @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 BeforeSelectionHandler}. */ public boolean selectTab(int index) { checkTabIndex(index); BeforeSelectionEvent<?> event = BeforeSelectionEvent.fire(this, index); if (event != null && event.isCanceled()) { return false; } // Check for -1. setSelectionStyle(selectedTab, false); if (index == -1) { selectedTab = null; return true; } selectedTab = panel.getWidget(index + 1); setSelectionStyle(selectedTab, true); panel.scrollToWidget(selectedTab); SelectionEvent.fire(this, index); return true; } /** * Inserts a new tab at the specified index. * * @param widget * widget to be used in the new tab * @param beforeIndex * the index before which this tab will be inserted */ protected void insertTabWidget(Widget widget, int beforeIndex) { checkInsertBeforeTabIndex(beforeIndex); ClickDelegatePanel delWidget = new ClickDelegatePanel(widget); delWidget.setStyleName(STYLENAME_DEFAULT); // Add a11y role "tab" SimplePanel focusablePanel = delWidget.getFocusablePanel(); Accessibility.setRole(focusablePanel.getElement(), Accessibility.ROLE_TAB); panel.insert(delWidget, beforeIndex + 1); setStyleName(DOM.getParent(delWidget.getElement()), STYLENAME_DEFAULT + "-wrapper", true); } /** * <b>Affected Elements:</b> * <ul> * <li>-tab# = The element containing the contents of the tab.</li> * <li>-tab-wrapper# = The cell containing the tab at the index.</li> * </ul> * * @see UIObject#onEnsureDebugId(String) */ @Override protected void onEnsureDebugId(String baseID) { super.onEnsureDebugId(baseID); int numTabs = getTabCount(); for (int i = 0; i < numTabs; i++) { ClickDelegatePanel delPanel = (ClickDelegatePanel) panel.getWidget(i + 1); SimplePanel focusablePanel = delPanel.getFocusablePanel(); ensureDebugId(focusablePanel.getElement(), baseID, "tab" + i); ensureDebugId(DOM.getParent(delPanel.getElement()), baseID, "tab-wrapper" + i); } } /** * Removes the tab at the specified index. * * @param index * the index of the tab to be removed */ protected 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); } private void checkInsertBeforeTabIndex(int beforeIndex) { if ((beforeIndex < 0) || (beforeIndex > getTabCount())) { throw new IndexOutOfBoundsException(); } } private void checkTabIndex(int index) { if ((index < -1) || (index >= getTabCount())) { throw new IndexOutOfBoundsException(); } } /** * Selects the tab corresponding to the widget for the tab. To be clear the * widget for the tab is not the widget INSIDE of the tab; it is the widget * used to represent the tab itself. * * @param tabWidget * The widget for the tab to be selected * @return true if the tab corresponding to the widget for the tab could * located and selected, false otherwise */ private boolean selectTabByTabWidget(Widget tabWidget) { int numTabs = panel.getWidgetCount() - 1; for (int i = 1; i < numTabs; ++i) { if (panel.getWidget(i) == tabWidget) { return selectTab(i - 1); } } return false; } private void setSelectionStyle(Widget item, boolean selected) { if (item != null) { if (selected) { item.addStyleName("crux-TabBarItem-selected"); setStyleName(DOM.getParent(item.getElement()), "crux-TabBarItem-wrapper-selected", true); } else { item.removeStyleName("crux-TabBarItem-selected"); setStyleName(DOM.getParent(item.getElement()), "crux-TabBarItem-wrapper-selected", false); } } } /** * Set of characteristic interfaces supported by {@link TabBar} tabs. * * Note that this set might expand over time, so implement this interface at * your own risk. */ public interface Tab extends HasAllKeyHandlers, HasClickHandlers, HasWordWrap { /** * Check if the underlying widget implements {@link HasWordWrap}. * * @return true if the widget implements {@link HasWordWrap} */ boolean hasWordWrap(); } /** * <code>ClickDelegatePanel</code> decorates any widget with the minimal * amount of machinery to receive clicks for delegation to the parent. * {@link SourcesClickEvents} is not implemented due to the fact that only a * single observer is needed. */ private class ClickDelegatePanel extends Composite implements Tab { private boolean enabled = true; private SimplePanel focusablePanel; ClickDelegatePanel(Widget child) { focusablePanel = new SimplePanel(); focusablePanel.getElement().setTabIndex(0); focusablePanel.setWidget(child); initWidget(focusablePanel); sinkEvents(Event.ONCLICK | Event.ONKEYDOWN); } public HandlerRegistration addClickHandler(ClickHandler handler) { return addHandler(handler, ClickEvent.getType()); } public HandlerRegistration addKeyDownHandler(KeyDownHandler handler) { return addHandler(handler, KeyDownEvent.getType()); } public HandlerRegistration addKeyPressHandler(KeyPressHandler handler) { return addDomHandler(handler, KeyPressEvent.getType()); } public HandlerRegistration addKeyUpHandler(KeyUpHandler handler) { return addDomHandler(handler, KeyUpEvent.getType()); } public SimplePanel getFocusablePanel() { return focusablePanel; } public boolean getWordWrap() { if (hasWordWrap()) { return ((HasWordWrap) focusablePanel.getWidget()).getWordWrap(); } throw new UnsupportedOperationException("Widget does not implement HasWordWrap"); } public boolean hasWordWrap() { return focusablePanel.getWidget() instanceof HasWordWrap; } @Override public void onBrowserEvent(Event event) { if (!enabled) { return; } // No need for call to super. switch (DOM.eventGetType(event)) { case Event.ONCLICK: RollingTabBar.this.selectTabByTabWidget(this); break; case Event.ONKEYDOWN: if (((char) DOM.eventGetKeyCode(event)) == KeyCodes.KEY_ENTER) { RollingTabBar.this.selectTabByTabWidget(this); } break; } super.onBrowserEvent(event); } public void setEnabled(boolean enabled) { this.enabled = enabled; } public void setWordWrap(boolean wrap) { if (hasWordWrap()) { ((HasWordWrap) focusablePanel.getWidget()).setWordWrap(wrap); } else { throw new UnsupportedOperationException("Widget does not implement HasWordWrap"); } } } }