Java tutorial
/* * Copyright 2010 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.cell.client; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.NativeEvent; import com.google.gwt.event.logical.shared.CloseEvent; import com.google.gwt.event.logical.shared.CloseHandler; import com.google.gwt.event.logical.shared.ValueChangeEvent; import com.google.gwt.event.logical.shared.ValueChangeHandler; import com.google.gwt.i18n.client.DateTimeFormat; import com.google.gwt.i18n.client.DateTimeFormat.PredefinedFormat; import com.google.gwt.safehtml.shared.SafeHtmlBuilder; import com.google.gwt.text.shared.SafeHtmlRenderer; import com.google.gwt.text.shared.SimpleSafeHtmlRenderer; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.Event.NativePreviewEvent; import com.google.gwt.user.client.ui.PopupPanel; import com.google.gwt.user.client.ui.PopupPanel.PositionCallback; import com.google.gwt.user.datepicker.client.DatePicker; import java.util.Date; /** * A {@link Cell} used to render and edit {@link Date}s. When a cell is selected * by clicking on it, a {@link DatePicker} is popped up. When a date is selected * using the {@link DatePicker}, the new date is passed to the * {@link ValueUpdater#update update} method of the {@link ValueUpdater} that * was passed to {@link #onBrowserEvent} for the click event. Note that this * means that the call to {@link ValueUpdater#update} will occur after {@link * #onBrowserEvent} has returned. Pressing the 'escape' key dismisses the {@link * DatePicker} popup without calling {@link ValueUpdater#update}. * * <p> * Each {@link DatePickerCell} has a unique {@link DatePicker} popup associated * with it; thus, if a single {@link DatePickerCell} is used as the cell for a * column in a table, only one entry in that column will be editable at a given * time. * </p> */ public class DatePickerCell extends AbstractEditableCell<Date, Date> { private static final int ESCAPE = 27; private final DatePicker datePicker; private final DateTimeFormat format; private int offsetX = 10; private int offsetY = 10; private Object lastKey; private Element lastParent; private int lastIndex; private int lastColumn; private Date lastValue; private PopupPanel panel; private final SafeHtmlRenderer<String> renderer; private ValueUpdater<Date> valueUpdater; /** * Constructs a new DatePickerCell that uses the date/time format given by * {@link DateTimeFormat#getFullDateFormat}. */ @SuppressWarnings("deprecation") public DatePickerCell() { this(DateTimeFormat.getFullDateFormat(), SimpleSafeHtmlRenderer.getInstance()); } /** * Constructs a new DatePickerCell that uses the given date/time format and a * {@link SimpleSafeHtmlRenderer}. * * @param format a {@link DateTimeFormat} instance */ public DatePickerCell(DateTimeFormat format) { this(format, SimpleSafeHtmlRenderer.getInstance()); } /** * Constructs a new DatePickerCell that uses the date/time format given by * {@link DateTimeFormat#getFullDateFormat} and the given * {@link SafeHtmlRenderer}. * * @param renderer a {@link SafeHtmlRenderer SafeHtmlRenderer<String>} instance */ public DatePickerCell(SafeHtmlRenderer<String> renderer) { this(DateTimeFormat.getFormat(PredefinedFormat.DATE_FULL), renderer); } /** * Constructs a new DatePickerCell that uses the given date/time format and * {@link SafeHtmlRenderer}. * * @param format a {@link DateTimeFormat} instance * @param renderer a {@link SafeHtmlRenderer SafeHtmlRenderer<String>} instance */ public DatePickerCell(DateTimeFormat format, SafeHtmlRenderer<String> renderer) { super("click", "keydown"); if (format == null) { throw new IllegalArgumentException("format == null"); } if (renderer == null) { throw new IllegalArgumentException("renderer == null"); } this.format = format; this.renderer = renderer; this.datePicker = new DatePicker(); this.panel = new PopupPanel(true, true) { @Override protected void onPreviewNativeEvent(NativePreviewEvent event) { if (Event.ONKEYUP == event.getTypeInt()) { if (event.getNativeEvent().getKeyCode() == ESCAPE) { // Dismiss when escape is pressed panel.hide(); } } } }; panel.addCloseHandler(new CloseHandler<PopupPanel>() { public void onClose(CloseEvent<PopupPanel> event) { lastKey = null; lastValue = null; lastIndex = -1; lastColumn = -1; if (lastParent != null && !event.isAutoClosed()) { // Refocus on the containing cell after the user selects a value, but // not if the popup is auto closed. lastParent.focus(); } lastParent = null; } }); panel.add(datePicker); // Hide the panel and call valueUpdater.update when a date is selected datePicker.addValueChangeHandler(new ValueChangeHandler<Date>() { public void onValueChange(ValueChangeEvent<Date> event) { // Remember the values before hiding the popup. Element cellParent = lastParent; Date oldValue = lastValue; Object key = lastKey; int index = lastIndex; int column = lastColumn; panel.hide(); // Update the cell and value updater. Date date = event.getValue(); setViewData(key, date); setValue(new Context(index, column, key), cellParent, oldValue); if (valueUpdater != null) { valueUpdater.update(date); } } }); } @Override public boolean isEditing(Context context, Element parent, Date value) { return lastKey != null && lastKey.equals(context.getKey()); } @Override public void onBrowserEvent(Context context, Element parent, Date value, NativeEvent event, ValueUpdater<Date> valueUpdater) { super.onBrowserEvent(context, parent, value, event, valueUpdater); if ("click".equals(event.getType())) { onEnterKeyDown(context, parent, value, event, valueUpdater); } } @Override public void render(Context context, Date value, SafeHtmlBuilder sb) { // Get the view data. Object key = context.getKey(); Date viewData = getViewData(key); if (viewData != null && viewData.equals(value)) { clearViewData(key); viewData = null; } String s = null; if (viewData != null) { s = format.format(viewData); } else if (value != null) { s = format.format(value); } if (s != null) { sb.append(renderer.render(s)); } } @Override protected void onEnterKeyDown(Context context, Element parent, Date value, NativeEvent event, ValueUpdater<Date> valueUpdater) { this.lastKey = context.getKey(); this.lastParent = parent; this.lastValue = value; this.lastIndex = context.getIndex(); this.lastColumn = context.getColumn(); this.valueUpdater = valueUpdater; Date viewData = getViewData(lastKey); Date date = (viewData == null) ? lastValue : viewData; datePicker.setCurrentMonth(date); datePicker.setValue(date); panel.setPopupPositionAndShow(new PositionCallback() { public void setPosition(int offsetWidth, int offsetHeight) { panel.setPopupPosition(lastParent.getAbsoluteLeft() + offsetX, lastParent.getAbsoluteTop() + offsetY); } }); } }