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 net.s17fabu.vip.gwt.showcase.client.content.i18n; import net.s17fabu.vip.gwt.showcase.client.ContentWidget; import com.google.gwt.event.dom.client.ChangeEvent; import com.google.gwt.event.dom.client.ChangeHandler; import com.google.gwt.event.dom.client.KeyUpEvent; import com.google.gwt.event.dom.client.KeyUpHandler; import com.google.gwt.i18n.client.Constants; import com.google.gwt.i18n.client.NumberFormat; import com.google.gwt.user.client.ui.Grid; import com.google.gwt.user.client.ui.Label; import com.google.gwt.user.client.ui.ListBox; import com.google.gwt.user.client.ui.TextBox; import com.google.gwt.user.client.ui.Widget; /** * Example file. */ public class CwNumberFormat extends ContentWidget { /** * The constants used in this Content Widget. */ public static interface CwConstants extends Constants, ContentWidget.CwConstants { String cwNumberFormatDescription(); String cwNumberFormatFailedToParseInput(); String cwNumberFormatFormattedLabel(); String cwNumberFormatInvalidPattern(); String cwNumberFormatName(); String cwNumberFormatPatternLabel(); String[] cwNumberFormatPatterns(); String cwNumberFormatValueLabel(); } /** * The {@link NumberFormat} that is currently being applied. */ private NumberFormat activeFormat = null; /** * An instance of the constants. */ private CwConstants constants; /** * The {@link Label} where the formatted value is displayed. */ private Label formattedBox = null; /** * The {@link TextBox} that displays the current pattern. */ private TextBox patternBox = null; /** * The {@link ListBox} that holds the patterns. */ private ListBox patternList = null; /** * The {@link TextBox} where the user enters a value. */ private TextBox valueBox = null; /** * Constructor. * * @param constants the constants */ public CwNumberFormat(CwConstants constants) { super(constants); this.constants = constants; } @Override public String getDescription() { return constants.cwNumberFormatDescription(); } @Override public String getName() { return constants.cwNumberFormatName(); } /** * Initialize this example. */ @Override public Widget onInitialize() { // Use a Grid to layout the content Grid layout = new Grid(4, 2); layout.setCellSpacing(5); // Add a field to select the pattern patternList = new ListBox(); patternList.setWidth("17em"); String[] patterns = constants.cwNumberFormatPatterns(); for (String pattern : patterns) { patternList.addItem(pattern); } patternList.addChangeHandler(new ChangeHandler() { public void onChange(ChangeEvent event) { updatePattern(); } }); layout.setHTML(0, 0, constants.cwNumberFormatPatternLabel()); layout.setWidget(0, 1, patternList); // Add a field to display the pattern patternBox = new TextBox(); patternBox.setWidth("17em"); patternBox.addKeyUpHandler(new KeyUpHandler() { public void onKeyUp(KeyUpEvent event) { updatePattern(); } }); layout.setWidget(1, 1, patternBox); // Add a field to set the value valueBox = new TextBox(); valueBox.setWidth("17em"); valueBox.setText("31415926535.897932"); valueBox.addKeyUpHandler(new KeyUpHandler() { public void onKeyUp(KeyUpEvent event) { updateFormattedValue(); } }); layout.setHTML(2, 0, constants.cwNumberFormatValueLabel()); layout.setWidget(2, 1, valueBox); // Add a field to display the formatted value formattedBox = new Label(); formattedBox.setWidth("17em"); layout.setHTML(3, 0, constants.cwNumberFormatFormattedLabel()); layout.setWidget(3, 1, formattedBox); // Return the layout Widget updatePattern(); return layout; } /** * Show an error message. Pass in null to clear the error message. * * @param errorMsg the error message */ private void showErrorMessage(String errorMsg) { if (errorMsg == null) { formattedBox.removeStyleName("cw-RedText"); } else { formattedBox.setText(errorMsg); formattedBox.addStyleName("cw-RedText"); } } /** * Update the formatted value based on the user entered value and pattern. */ private void updateFormattedValue() { String sValue = valueBox.getText(); if (!sValue.equals("")) { try { double value = Double.parseDouble(sValue); String formattedValue = activeFormat.format(value); formattedBox.setText(formattedValue); showErrorMessage(null); } catch (NumberFormatException e) { showErrorMessage(constants.cwNumberFormatFailedToParseInput()); } } else { formattedBox.setText("<None>"); } } /** * Update the selected pattern based on the pattern in the list. */ private void updatePattern() { switch (patternList.getSelectedIndex()) { case 0: activeFormat = NumberFormat.getDecimalFormat(); patternBox.setText(activeFormat.getPattern()); patternBox.setEnabled(false); break; case 1: activeFormat = NumberFormat.getCurrencyFormat(); patternBox.setText(activeFormat.getPattern()); patternBox.setEnabled(false); break; case 2: activeFormat = NumberFormat.getScientificFormat(); patternBox.setText(activeFormat.getPattern()); patternBox.setEnabled(false); break; case 3: activeFormat = NumberFormat.getPercentFormat(); patternBox.setText(activeFormat.getPattern()); patternBox.setEnabled(false); break; case 4: patternBox.setEnabled(true); String pattern = patternBox.getText(); try { activeFormat = NumberFormat.getFormat(pattern); } catch (IllegalArgumentException e) { showErrorMessage(constants.cwNumberFormatInvalidPattern()); return; } break; } // Update the formatted value updateFormattedValue(); } }