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.examples.cellview; import com.google.gwt.cell.client.DatePickerCell; import com.google.gwt.cell.client.FieldUpdater; import com.google.gwt.cell.client.TextInputCell; import com.google.gwt.core.client.EntryPoint; import com.google.gwt.i18n.client.DateTimeFormat; import com.google.gwt.i18n.client.DateTimeFormat.PredefinedFormat; import com.google.gwt.user.cellview.client.CellTable; import com.google.gwt.user.cellview.client.Column; import com.google.gwt.user.cellview.client.HasKeyboardSelectionPolicy.KeyboardSelectionPolicy; import com.google.gwt.user.cellview.client.TextColumn; import com.google.gwt.user.client.Window; import com.google.gwt.user.client.ui.RootPanel; import com.google.gwt.view.client.ProvidesKey; import java.util.Arrays; import java.util.Date; import java.util.List; /** * Example of using a {@link FieldUpdater} with a {@link CellTable}. */ public class CellTableFieldUpdaterExampleComplex implements EntryPoint { /** * A simple data type that represents a contact with a unique ID. */ private static class Contact { private static int nextId = 0; private final int id; private final String address; private Date birthday; private String name; public Contact(String name, Date birthday, String address) { nextId++; this.id = nextId; this.name = name; this.birthday = birthday; this.address = address; } } /** * The list of data to display. */ private static final List<Contact> CONTACTS = Arrays.asList( new Contact("John", new Date(80, 4, 12), "123 Fourth Avenue"), new Contact("Joe", new Date(85, 2, 22), "22 Lance Ln"), new Contact("George", new Date(46, 6, 6), "1600 Pennsylvania Avenue")); /** * The key provider that allows us to identify Contacts even if a field * changes. We identify contacts by their unique ID. */ private static final ProvidesKey<Contact> KEY_PROVIDER = new ProvidesKey<CellTableFieldUpdaterExampleComplex.Contact>() { @Override public Object getKey(Contact item) { return item.id; } }; @Override public void onModuleLoad() { // Create a CellTable with a key provider. final CellTable<Contact> table = new CellTable<Contact>(KEY_PROVIDER); table.setKeyboardSelectionPolicy(KeyboardSelectionPolicy.ENABLED); // Add a text input column to edit the name. final TextInputCell nameCell = new TextInputCell(); Column<Contact, String> nameColumn = new Column<Contact, String>(nameCell) { @Override public String getValue(Contact object) { return object.name; } }; table.addColumn(nameColumn, "Name"); // Add a field updater to be notified when the user enters a new name. nameColumn.setFieldUpdater(new FieldUpdater<Contact, String>() { @Override public void update(int index, Contact object, String value) { // Validate the data. if (value.length() < 3) { Window.alert("Names must be at least three characters long."); /* * Clear the view data. The view data contains the pending change and * allows the table to render with the pending value until the data is * committed. If the data is committed into the object, the view data * is automatically cleared out. If the data is not committed because * it is invalid, you must delete. */ nameCell.clearViewData(KEY_PROVIDER.getKey(object)); // Redraw the table. table.redraw(); return; } // Inform the user of the change. Window.alert("You changed the name of " + object.name + " to " + value); // Push the changes into the Contact. At this point, you could send an // asynchronous request to the server to update the database. object.name = value; // Redraw the table with the new data. table.redraw(); } }); // Add a date column to show the birthday. Column<Contact, Date> dateColumn = new Column<Contact, Date>(new DatePickerCell()) { @Override public Date getValue(Contact object) { return object.birthday; } }; table.addColumn(dateColumn, "Birthday"); // Add a field updater to be notified when the user enters a new birthday. dateColumn.setFieldUpdater(new FieldUpdater<Contact, Date>() { @Override public void update(int index, Contact object, Date value) { Window.alert("You changed the birthday of " + object.name + " to " + DateTimeFormat.getFormat(PredefinedFormat.DATE_LONG).format(value)); // Push the changes into the Contact. object.birthday = value; // Redraw the table with the new data. table.redraw(); } }); // Add a text column to show the address. TextColumn<Contact> addressColumn = new TextColumn<Contact>() { @Override public String getValue(Contact object) { return object.address; } }; table.addColumn(addressColumn, "Address"); // Set the total row count. This isn't strictly necessary, but it affects // paging calculations, so its good habit to keep the row count up to date. table.setRowCount(CONTACTS.size(), true); // Push the data into the widget. table.setRowData(0, CONTACTS); // Add it to the root panel. RootPanel.get().add(table); } }