Java tutorial
/** * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.waveprotocol.wave.client.widget.menu; import com.google.gwt.core.client.GWT; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.StyleInjector; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.dom.client.MouseDownEvent; import com.google.gwt.event.dom.client.MouseDownHandler; import com.google.gwt.event.dom.client.MouseUpEvent; import com.google.gwt.event.dom.client.MouseUpHandler; import com.google.gwt.resources.client.ClientBundle; import com.google.gwt.resources.client.CssResource; import com.google.gwt.resources.client.CssResource.NotStrict; import com.google.gwt.user.client.Command; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.Widget; import org.waveprotocol.wave.client.common.webdriver.DebugClassHelper; import org.waveprotocol.wave.client.widget.popup.AlignedPopupPositioner; import org.waveprotocol.wave.client.widget.popup.PopupChromeFactory; import org.waveprotocol.wave.client.widget.popup.PopupEventListener; import org.waveprotocol.wave.client.widget.popup.PopupFactory; import org.waveprotocol.wave.client.widget.popup.RelativePopupPositioner; import org.waveprotocol.wave.client.widget.popup.UniversalPopup; import org.waveprotocol.wave.model.util.Pair; /** * * Desktop version for rendering a vertical sub-menu. * I don't like it any more than you do. */ public class PopupMenu implements Menu { interface Resources extends ClientBundle { /** CSS class names used by DesktopSubMenu. These are used in Menu.css */ interface Css extends CssResource { String item(); String disabled(); String divider(); } @Source("Menu.css") @NotStrict // TODO(user): make Strict by including/inheriting "verticalSeparator" Css css(); } /** * An implementation of {@code MenuItem} for a {@code PopupMenu}. * */ private class PopupMenuItem extends Label implements MenuItem { /** * Whether the default state of the item is enabled or not. */ private final boolean defaultEnabled; /** * Whether the item is enabled or not. */ private boolean enabled; /** * The command to execute when clicked. */ private Command command; /** Should clicking this menu item hide the popup? */ private final boolean hide; /** * Constructs a {@PopupMenuItem} * * @param text The text label for the item. * @param cmd The command to run when the item is clicked. * @param isEnabled True if this menu item is enabled. * @param hide True if clicking this menu item should hide the popup. */ public PopupMenuItem(String text, Command cmd, boolean isEnabled, boolean hide) { super(text); setStyleName(RESOURCES.css().item()); setEnabled(isEnabled); defaultEnabled = isEnabled; command = cmd; this.hide = hide; if (isPreClicked) { // If this menu is pre-clicked it doesn't require a full click to select // an item, just a mouseup over the item. If the user then does click the // item then that will also give a mouseup so this handler will deal with // that case as well. addMouseUpHandler(new MouseUpHandler() { @Override public void onMouseUp(MouseUpEvent event) { onClicked(); } }); } else { addClickHandler(new ClickHandler() { public void onClick(ClickEvent e) { onClicked(); } }); } // Ensure that clicking this menu item doesn't affect the current selection. addMouseDownHandler(PREVENT_DEFAULT_HANDLER); } private void onClicked() { if (enabled) { if (command != null) { command.execute(); } if (hide) { popup.hide(); } } } @Override public void setEnabled(boolean enabled) { if (!enabled) { addStyleName(RESOURCES.css().disabled()); } else { removeStyleName(RESOURCES.css().disabled()); } this.enabled = enabled; } @Override public void resetEnabled() { setEnabled(defaultEnabled); } @Override public final void setDebugClassTODORename(String debugClass) { DebugClassHelper.addDebugClass(this, debugClass); } /** Set the command to me executed when this menu item is clicked */ public void setCommand(Command cmd) { command = cmd; } } /** * Mouse down handler that prevents the event's default action thereby, the * way it's used here, preventing mouse downs from affecting selection. */ private static final MouseDownHandler PREVENT_DEFAULT_HANDLER = new MouseDownHandler() { @Override public void onMouseDown(MouseDownEvent event) { event.preventDefault(); } }; /** The singleton instance of our resources. */ private static final Resources RESOURCES = GWT.create(Resources.class); public static final Resources.Css CSS = RESOURCES.css(); /** * Inject the CSS once. */ static { StyleInjector.inject(RESOURCES.css().getText()); } /** The popup to use for this submenu */ private final UniversalPopup popup; /** * True if the user has already clicked a mouse button and so just releasing the * mouse over an item should count as a click. */ private final boolean isPreClicked; /** * Create a new PopupMenu * * @param relative The reference element for the positioner. * @param positioner The positioner to position the menu popup. */ public PopupMenu(Element relative, RelativePopupPositioner positioner, boolean isPreClicked) { popup = PopupFactory.createPopup(relative, positioner, PopupChromeFactory.createPopupChrome(), true); this.isPreClicked = isPreClicked; } /** * Create a new PopupMenu * * @param relative The reference element for the positioner. * @param positioner The positioner to position the menu popup. */ public PopupMenu(Element relative, RelativePopupPositioner positioner) { this(relative, positioner, false); } @Override public void addDivider() { Widget divider = new Label(); divider.setStyleName(RESOURCES.css().divider()); popup.add(divider); } @Override public Pair<Menu, MenuItem> createSubMenu(String title, boolean enabled) { PopupMenuItem item = addItem(title, null, enabled, false); final PopupMenu menu = new PopupMenu(item.getElement(), AlignedPopupPositioner.BELOW_RIGHT); item.setCommand(new Command() { @Override public void execute() { menu.show(); } }); return new Pair<Menu, MenuItem>(menu, item); } @Override public MenuItem addItem(String label, final Command cmd, boolean enabled) { return addItem(label, cmd, enabled, true); } private PopupMenuItem addItem(String label, final Command cmd, boolean enabled, boolean hideOnClick) { PopupMenuItem item = new PopupMenuItem(label, cmd, enabled, hideOnClick); popup.add(item); return item; } /** * Removes an item previously added to the menu. * * @param item The item to remove. */ public boolean removeItem(MenuItem item) { if (item instanceof PopupMenuItem) { PopupMenuItem popup = (PopupMenuItem) item; return this.popup.remove(popup); } return false; } /** * Hide the menu. */ public void hide() { popup.hide(); } /** * Show the menu. */ public void show() { popup.show(); } /** * Set the debugClassName (for Webdriver) on the popup window. * @param dcName debugClassName to set. */ public void setDebugClass(String dcName) { popup.setDebugClass(dcName); } @Override public void clearItems() { popup.clear(); } /** * Add a PopupEventListener to this menu. * @param listener The listener to add. */ public void addPopupEventListener(PopupEventListener listener) { popup.addPopupEventListener(listener); } /** * Remove a PopupEventListener to this menu. * @param listener The listener to remove. */ public void removePopupEventListener(PopupEventListener listener) { popup.removePopupEventListener(listener); } /** * Indicates that clicks inside the given widget should not be considered * 'outside' of the popup menu, for purposes of auto-hiding. * * @param w A widget. */ public void associateWidget(Widget w) { popup.associateWidget(w); } }