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.gen2.table.client; import com.google.gwt.core.client.GWT; import com.google.gwt.event.dom.client.ClickEvent; import com.google.gwt.event.dom.client.ClickHandler; import com.google.gwt.event.dom.client.KeyCodes; import com.google.gwt.event.dom.client.KeyPressEvent; import com.google.gwt.event.dom.client.KeyPressHandler; import com.google.gwt.gen2.table.event.client.PageChangeEvent; import com.google.gwt.gen2.table.event.client.PageChangeHandler; import com.google.gwt.gen2.table.event.client.PageCountChangeEvent; import com.google.gwt.gen2.table.event.client.PageCountChangeHandler; import com.google.gwt.gen2.table.event.client.PageLoadEvent; import com.google.gwt.gen2.table.event.client.PageLoadHandler; import com.google.gwt.gen2.table.event.client.PagingFailureEvent; import com.google.gwt.gen2.table.event.client.PagingFailureHandler; import com.google.gwt.user.client.ui.AbstractImagePrototype; 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.HorizontalPanel; import com.google.gwt.user.client.ui.Image; import com.google.gwt.user.client.ui.ImageBundle; import com.google.gwt.user.client.ui.TextBox; import com.google.gwt.user.client.ui.TextBoxBase; import com.google.gwt.user.client.ui.Widget; /** * A panel that wraps a {@link PagingScrollTable} and includes options to * manipulate the page. * * <h3>CSS Style Rules</h3> * * <ul class="css"> * * <li>.gwt-PagingOptions { applied to the entire widget }</li> * * <li>.gwt-PagingOptions .errorMessage { applied to the error message }</li> * * <li>.pagingOptionsFirstPage { the first page button }</li> * * <li>.pagingOptionsLastPage { the last page button }</li> * * <li>.pagingOptionsNextPage { the next page button }</li> * * <li>.pagingOptionsPreviousPage { the previous page button }</li> * * </ul> */ public class PagingOptions extends Composite { /** * An {@link com.google.gwt.user.client.ui.ImageBundle} that provides images * for {@link PagingOptions}. */ public static interface PagingOptionsImages extends ImageBundle { /** * An image used to navigate to the first page. * * @return a prototype of this image */ AbstractImagePrototype pagingOptionsFirstPage(); /** * An image used to navigate to the last page. * * @return a prototype of this image */ AbstractImagePrototype pagingOptionsLastPage(); /** * An image used to navigate to the next page. * * @return a prototype of this image */ AbstractImagePrototype pagingOptionsNextPage(); /** * An image used to navigate to the previous page. * * @return a prototype of this image */ AbstractImagePrototype pagingOptionsPrevPage(); } /** * The default style name. */ public static final String DEFAULT_STYLENAME = "gwt-PagingOptions"; public static final String STYLENAME_PREFIX = "pagingOptions"; /** * The label used to display errors. */ private HTML errorLabel; /** * Goto first page button. */ private Image firstImage; /** * Goto last page button. */ private Image lastImage; /** * The loading image. */ private Image loadingImage; /** * Goto next page button. */ private Image nextImage; /** * The HTML field that contains the number of pages. */ private HTML numPagesLabel; /** * Goto previous page button. */ private Image prevImage; /** * The box where the user can select the current page. */ private TextBox curPageBox = new TextBox(); /** * The table being affected. */ private PagingScrollTable<?> table; /** * Constructor. * * @param table the table being ad */ public PagingOptions(PagingScrollTable<?> table) { this(table, GWT.<PagingOptionsImages>create(PagingOptionsImages.class)); } /** * Constructor. * * @param table the table being affected * @param images the images to use */ public PagingOptions(PagingScrollTable<?> table, PagingOptionsImages images) { this.table = table; // Create the main widget HorizontalPanel hPanel = new HorizontalPanel(); initWidget(hPanel); hPanel.setVerticalAlignment(HasVerticalAlignment.ALIGN_MIDDLE); setStyleName(DEFAULT_STYLENAME); // Create the paging image buttons createPageButtons(images); // Create the current page box createCurPageBox(); // Create the page count label numPagesLabel = new HTML(); // Create the loading image loadingImage = new Image(GWT.getModuleBaseURL() + "scrollTableLoading.gif"); loadingImage.setVisible(false); // Create the error label errorLabel = new HTML(); errorLabel.setStylePrimaryName("errorMessage"); // Add the widgets to the panel hPanel.add(createSpacer()); hPanel.add(firstImage); hPanel.add(createSpacer()); hPanel.add(prevImage); hPanel.add(createSpacer()); hPanel.add(curPageBox); hPanel.add(createSpacer()); hPanel.add(numPagesLabel); hPanel.add(createSpacer()); hPanel.add(nextImage); hPanel.add(createSpacer()); hPanel.add(lastImage); hPanel.add(createSpacer()); hPanel.add(loadingImage); hPanel.add(errorLabel); // Add handlers to the table table.addPageLoadHandler(new PageLoadHandler() { public void onPageLoad(PageLoadEvent event) { loadingImage.setVisible(false); errorLabel.setHTML(""); } }); table.addPageChangeHandler(new PageChangeHandler() { public void onPageChange(PageChangeEvent event) { curPageBox.setText((event.getNewPage() + 1) + ""); loadingImage.setVisible(true); errorLabel.setHTML(""); } }); table.addPagingFailureHandler(new PagingFailureHandler() { public void onPagingFailure(PagingFailureEvent event) { loadingImage.setVisible(false); errorLabel.setHTML(event.getException().getMessage()); } }); table.addPageCountChangeHandler(new PageCountChangeHandler() { public void onPageCountChange(PageCountChangeEvent event) { setPageCount(event.getNewPageCount()); } }); setPageCount(table.getPageCount()); } /** * @return the {@link PagingScrollTable}. */ public PagingScrollTable<?> getPagingScrollTable() { return table; } /** * Create a widget that can be used to add space. * * @return a spacer widget */ protected Widget createSpacer() { return new HTML(" "); } /** * Create a box that holds the current page. */ private void createCurPageBox() { // Setup the widget curPageBox.setWidth("3em"); curPageBox.setText("1"); curPageBox.setTextAlignment(TextBoxBase.ALIGN_RIGHT); // Disallow non-numeric pages KeyPressHandler handler = new KeyPressHandler() { public void onKeyPress(KeyPressEvent event) { char charCode = event.getCharCode(); if (charCode == KeyCodes.KEY_ENTER) { PagingOptions.this.table.gotoPage(getPagingBoxValue(), false); } else if (!Character.isDigit(charCode) && (charCode != KeyCodes.KEY_TAB) && (charCode != KeyCodes.KEY_BACKSPACE) && (charCode != KeyCodes.KEY_DELETE) && (charCode != KeyCodes.KEY_ENTER) && (charCode != KeyCodes.KEY_HOME) && (charCode != KeyCodes.KEY_END) && (charCode != KeyCodes.KEY_LEFT) && (charCode != KeyCodes.KEY_UP) && (charCode != KeyCodes.KEY_RIGHT) && (charCode != KeyCodes.KEY_DOWN)) { curPageBox.cancelKey(); } } }; // Add the handler curPageBox.addKeyPressHandler(handler); } /** * Create a paging image buttons. * * @param images the images to use */ private void createPageButtons(PagingOptionsImages images) { // Create the images firstImage = images.pagingOptionsFirstPage().createImage(); firstImage.addStyleName(STYLENAME_PREFIX + "FirstPage"); prevImage = images.pagingOptionsPrevPage().createImage(); prevImage.addStyleName(STYLENAME_PREFIX + "PreviousPage"); nextImage = images.pagingOptionsNextPage().createImage(); nextImage.addStyleName(STYLENAME_PREFIX + "NextPage"); lastImage = images.pagingOptionsLastPage().createImage(); lastImage.addStyleName(STYLENAME_PREFIX + "LastPage"); // Create the listener ClickHandler handler = new ClickHandler() { public void onClick(ClickEvent event) { Object source = event.getSource(); if (source == firstImage) { table.gotoFirstPage(); } else if (source == lastImage) { table.gotoLastPage(); } else if (source == nextImage) { table.gotoNextPage(); } else if (source == prevImage) { table.gotoPreviousPage(); } } }; // Add the listener to each image firstImage.addClickHandler(handler); prevImage.addClickHandler(handler); nextImage.addClickHandler(handler); lastImage.addClickHandler(handler); } /** * Get the value of in the page box. If the value is invalid, it will be set * to 1 automatically. * * @return the value in the page box */ private int getPagingBoxValue() { int page = 0; try { page = Integer.parseInt(curPageBox.getText()) - 1; } catch (NumberFormatException e) { // This will catch an empty box curPageBox.setText("1"); } // Replace values less than 1 if (page < 1) { curPageBox.setText("1"); page = 0; } // Return the 0 based page, not the 1 based visible value return page; } /** * Set the page count. * * @param pageCount the current page count */ private void setPageCount(int pageCount) { if (pageCount < 0) { numPagesLabel.setHTML(""); lastImage.setVisible(false); } else { numPagesLabel.setHTML("of " + pageCount); numPagesLabel.setVisible(true); lastImage.setVisible(true); } } }