/*
* 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.cell;
import com.google.gwt.cell.client.AbstractCell;
import com.google.gwt.cell.client.Cell;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.safecss.shared.SafeStyles;
import com.google.gwt.safecss.shared.SafeStylesUtils;
import com.google.gwt.safehtml.client.SafeHtmlTemplates;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlBuilder;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.google.gwt.user.cellview.client.CellList;
import com.google.gwt.user.client.ui.RootPanel;
import java.util.Arrays;
import java.util.List;
/**
* Example of creating a custom {@link Cell}.
*/
public class CellExample implements EntryPoint {
/**
* A custom {@link Cell} used to render a string that contains the name of a
* color.
*/
static class ColorCell extends AbstractCell<String> {
/**
* The HTML templates used to render the cell.
*/
interface Templates extends SafeHtmlTemplates {
/**
* The template for this Cell, which includes styles and a value.
*
* @param styles the styles to include in the style attribute of the div
* @param value the safe value. Since the value type is {@link SafeHtml},
* it will not be escaped before including it in the template.
* Alternatively, you could make the value type String, in which
* case the value would be escaped.
* @return a {@link SafeHtml} instance
*/
@SafeHtmlTemplates.Template("<div style=\"{0}\">{1}</div>")
SafeHtml cell(SafeStyles styles, SafeHtml value);
}
/**
* Create a singleton instance of the templates used to render the cell.
*/
private static Templates templates = GWT.create(Templates.class);
@Override
public void render(Context context, String value, SafeHtmlBuilder sb) {
/*
* Always do a null check on the value. Cell widgets can pass null to
* cells if the underlying data contains a null, or if the data arrives
* out of order.
*/
if (value == null) {
return;
}
// If the value comes from the user, we escape it to avoid XSS attacks.
SafeHtml safeValue = SafeHtmlUtils.fromString(value);
// Use the template to create the Cell's html.
SafeStyles styles = SafeStylesUtils.forTrustedColor(safeValue.asString());
SafeHtml rendered = templates.cell(styles, safeValue);
sb.append(rendered);
}
}
/**
* The list of data to display.
*/
private static final List<String> COLORS = Arrays.asList("red", "green", "blue", "violet",
"black", "gray");
@Override
public void onModuleLoad() {
// Create a cell to render each value.
ColorCell cell = new ColorCell();
// Use the cell in a CellList.
CellList<String> cellList = new CellList<String>(cell);
// Push the data into the widget.
cellList.setRowData(0, COLORS);
// Add it to the root panel.
RootPanel.get().add(cellList);
}
}