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.appspot.codsallarts.client; import java.util.List; import com.google.gwt.core.client.GWT; import com.google.gwt.event.logical.shared.HasSelectionHandlers; import com.google.gwt.event.logical.shared.ResizeEvent; import com.google.gwt.event.logical.shared.ResizeHandler; import com.google.gwt.event.logical.shared.SelectionHandler; import com.google.gwt.event.shared.HandlerRegistration; import com.google.gwt.i18n.client.LocaleInfo; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.AbstractImagePrototype; import com.google.gwt.user.client.ui.Composite; import com.google.gwt.user.client.ui.DecoratorPanel; import com.google.gwt.user.client.ui.FlexTable; import com.google.gwt.user.client.ui.FlowPanel; import com.google.gwt.user.client.ui.Grid; import com.google.gwt.user.client.ui.HTML; import com.google.gwt.user.client.ui.HasHorizontalAlignment; import com.google.gwt.user.client.ui.HasVerticalAlignment; import com.google.gwt.user.client.ui.HorizontalPanel; import com.google.gwt.user.client.ui.SimplePanel; import com.google.gwt.user.client.ui.Tree; import com.google.gwt.user.client.ui.TreeImages; import com.google.gwt.user.client.ui.TreeItem; import com.google.gwt.user.client.ui.Widget; import com.google.gwt.user.client.ui.FlexTable.FlexCellFormatter; import com.google.gwt.user.client.ui.HTMLTable.CellFormatter; /** * <p> * A generic application that includes a title bar, main menu, content area, and * some external links at the top. * </p> * <h3>CSS Style Rules</h3> * * <ul class="css"> * * <li>.Application { Applied to the entire Application }</li> * * <li>.Application-top { The top portion of the Application }</li> * * <li>.Application-title { The title widget }</li> * * <li>.Application-links { The main external links }</li> * * <li>.Application-options { The options widget }</li> * * <li>.Application-menu { The main menu }</li> * * <li>.Application-content-wrapper { The scrollable element around the content }</li> * * </ul> */ public class Application extends Composite implements ResizeHandler, HasSelectionHandlers<TreeItem> { /** * Images used in the {@link Application}. */ public interface ApplicationImages extends TreeImages { /** * An image indicating a leaf. * * @return a prototype of this image */ @Resource("noimage.png") AbstractImagePrototype treeLeaf(); } /** * The base style name. */ public static final String DEFAULT_STYLE_NAME = "Application"; /** * The panel that contains the menu and content. */ private HorizontalPanel bottomPanel; /** * The decorator around the content. */ private DecoratorPanel contentDecorator; /** * The main wrapper around the content and content title. */ private Grid contentLayout; /** * The wrapper around the content. */ private SimplePanel contentWrapper; /** * The panel that holds the main links. */ private HorizontalPanel linksPanel; /** * The main menu. */ private Tree mainMenu; private SimplePanel navigationPanel; /** * The last known width of the window. */ private int windowWidth = -1; /** * The panel that contains the title widget and links. */ private FlexTable topPanel; /** * Constructor. */ public Application() { // Setup the main layout widget FlowPanel layout = new FlowPanel(); initWidget(layout); // Setup the top panel with the title and links createTopPanel(); layout.add(topPanel); // Add the main menu bottomPanel = new HorizontalPanel(); bottomPanel.setWidth("100%"); bottomPanel.setSpacing(0); bottomPanel.setVerticalAlignment(HasVerticalAlignment.ALIGN_TOP); layout.add(bottomPanel); // Setup the content layout contentLayout = new Grid(2, 1); contentLayout.setStyleName("Application-content-grid"); contentLayout.setCellPadding(0); contentLayout.setCellSpacing(0); contentDecorator = new DecoratorPanel(); contentDecorator.setWidget(contentLayout); contentDecorator.addStyleName(DEFAULT_STYLE_NAME + "-content-decorator"); bottomPanel.add(contentDecorator); if (LocaleInfo.getCurrentLocale().isRTL()) { bottomPanel.setCellHorizontalAlignment(contentDecorator, HasHorizontalAlignment.ALIGN_LEFT); contentDecorator.getElement().setAttribute("align", "LEFT"); } else { bottomPanel.setCellHorizontalAlignment(contentDecorator, HasHorizontalAlignment.ALIGN_RIGHT); contentDecorator.getElement().setAttribute("align", "RIGHT"); } CellFormatter formatter = contentLayout.getCellFormatter(); // Add the content title setContentTitle(new HTML("Welcome")); formatter.setStyleName(0, 0, DEFAULT_STYLE_NAME + "-content-title"); // Add the content wrapper contentWrapper = new SimplePanel(); contentLayout.setWidget(1, 0, contentWrapper); formatter.setStyleName(1, 0, DEFAULT_STYLE_NAME + "-content-wrapper"); setContent(null); //createMainMenu(); //bottomPanel.add(mainMenu); navigationPanel = new SimplePanel(); navigationPanel.addStyleName(DEFAULT_STYLE_NAME + "-nav"); bottomPanel.add(navigationPanel); // Add a window resize handler Window.addResizeHandler(this); } /** * Add a link to the top of the page. * * @param link the widget to add to the mainLinks */ public void setLinks(List<Widget> links) { boolean first = true; for (Widget w : links) { if (!first) { linksPanel.add(new HTML(" | ")); first = false; } linksPanel.add(w); } } public HandlerRegistration addSelectionHandler(SelectionHandler<TreeItem> handler) { return mainMenu.addSelectionHandler(handler); } /** * @return the {@link Widget} in the content area */ public Widget getContent() { return contentWrapper.getWidget(); } /** * @return the content title widget */ public Widget getContentTitle() { return contentLayout.getWidget(0, 0); } /** * @return the main menu. */ public Tree getMainMenu() { return mainMenu; } /** * @return the {@link Widget} used as the title */ public Widget getTitleWidget() { return topPanel.getWidget(0, 0); } public void onResize(ResizeEvent event) { onWindowResized(event.getWidth(), event.getHeight()); } public void onWindowResized(int width, int height) { if (width == windowWidth || width < 1) { return; } windowWidth = width; onWindowResizedImpl(width); } /** * Set the {@link Widget} to display in the content area. * * @param content the content widget */ public void setContent(Widget content) { if (content == null) { contentWrapper.setWidget(new HTML("Coming Soon")); } else { contentWrapper.setWidget(content); } } public void setNavBar(Widget w) { navigationPanel.add(w); } /** * Set the title of the content area. * * @param title the content area title */ public void setContentTitle(Widget title) { contentLayout.setWidget(0, 0, title); } /** * Set the {@link Widget} to use as options, which appear to the right of the * title bar. * * @param options the options widget */ public void setOptionsWidget(Widget options) { topPanel.setWidget(1, 1, options); } /** * Set the {@link Widget} to use as the title bar. * * @param title the title widget */ public void setTitleWidget(Widget title) { topPanel.setWidget(1, 0, title); } @Override protected void onLoad() { super.onLoad(); onWindowResized(Window.getClientWidth(), Window.getClientHeight()); } @Override protected void onUnload() { super.onUnload(); windowWidth = -1; } protected void onWindowResizedImpl(int width) { if (true) return; int navWidth = navigationPanel.getOffsetWidth(); int contentWidth = Math.max(width - navWidth - 30, 1); int contentWidthInner = Math.max(contentWidth - 10, 1); bottomPanel.setCellWidth(navigationPanel, navWidth + "px"); bottomPanel.setCellWidth(contentDecorator, contentWidth + "px"); contentLayout.getCellFormatter().setWidth(0, 0, contentWidthInner + "px"); contentLayout.getCellFormatter().setWidth(1, 0, contentWidthInner + "px"); } /** * Create the main menu. */ @SuppressWarnings("unused") private void createMainMenu() { // Setup the main menu ApplicationImages treeImages = GWT.create(ApplicationImages.class); mainMenu = new Tree(treeImages); mainMenu.setAnimationEnabled(true); mainMenu.addStyleName(DEFAULT_STYLE_NAME + "-menu"); } /** * Create the panel at the top of the page that contains the title and links. */ private void createTopPanel() { boolean isRTL = LocaleInfo.getCurrentLocale().isRTL(); topPanel = new FlexTable(); topPanel.setCellPadding(0); topPanel.setCellSpacing(0); topPanel.setStyleName(DEFAULT_STYLE_NAME + "-top"); FlexCellFormatter formatter = topPanel.getFlexCellFormatter(); // Setup the links cell linksPanel = new HorizontalPanel(); topPanel.setWidget(0, 0, linksPanel); formatter.setStyleName(0, 0, DEFAULT_STYLE_NAME + "-links"); if (isRTL) { formatter.setHorizontalAlignment(0, 0, HasHorizontalAlignment.ALIGN_LEFT); } else { formatter.setHorizontalAlignment(0, 0, HasHorizontalAlignment.ALIGN_RIGHT); } formatter.setColSpan(0, 0, 2); // Setup the title cell setTitleWidget(null); formatter.setStyleName(1, 0, DEFAULT_STYLE_NAME + "-title"); // Setup the options cell setOptionsWidget(null); formatter.setStyleName(1, 1, DEFAULT_STYLE_NAME + "-options"); if (isRTL) { formatter.setHorizontalAlignment(1, 1, HasHorizontalAlignment.ALIGN_LEFT); } else { formatter.setHorizontalAlignment(1, 1, HasHorizontalAlignment.ALIGN_RIGHT); } // Align the content to the top topPanel.getRowFormatter().setVerticalAlign(0, HasVerticalAlignment.ALIGN_TOP); topPanel.getRowFormatter().setVerticalAlign(1, HasVerticalAlignment.ALIGN_TOP); } }