/*
* 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.view;
import com.google.gwt.cell.client.TextCell;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.user.cellview.client.CellList;
import com.google.gwt.user.cellview.client.SimplePager;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.VerticalPanel;
import com.google.gwt.view.client.AsyncDataProvider;
import com.google.gwt.view.client.HasData;
import com.google.gwt.view.client.Range;
import java.util.ArrayList;
import java.util.List;
/**
* Example of {@link AsyncDataProvider}.
*/
public class AsyncDataProviderExample implements EntryPoint {
/**
* A custom {@link AsyncDataProvider}.
*/
private static class MyDataProvider extends AsyncDataProvider<String> {
/**
* {@link #onRangeChanged(HasData)} is called when the table requests a new
* range of data. You can push data back to the displays using
* {@link #updateRowData(int, List)}.
*/
@Override
protected void onRangeChanged(HasData<String> display) {
// Get the new range.
final Range range = display.getVisibleRange();
/*
* Query the data asynchronously. If you are using a database, you can
* make an RPC call here. We'll use a Timer to simulate a delay.
*/
new Timer() {
@Override
public void run() {
// We are creating fake data. Normally, the data will come from a
// server.
int start = range.getStart();
int length = range.getLength();
List<String> newData = new ArrayList<String>();
for (int i = start; i < start + length; i++) {
newData.add("Item " + i);
}
// Push the data to the displays. AsyncDataProvider will only update
// displays that are within range of the data.
updateRowData(start, newData);
}
}.schedule(3000);
}
}
public void onModuleLoad() {
// Create a CellList.
CellList<String> cellList = new CellList<String>(new TextCell());
// Create a data provider.
MyDataProvider dataProvider = new MyDataProvider();
// Add the cellList to the dataProvider.
dataProvider.addDataDisplay(cellList);
// Create paging controls.
SimplePager pager = new SimplePager();
pager.setDisplay(cellList);
// Add the widgets to the root panel.
VerticalPanel vPanel = new VerticalPanel();
vPanel.add(pager);
vPanel.add(cellList);
RootPanel.get().add(vPanel);
}
}