com.chinarewards.gwt.elt.client.widget.SortableHeader.java Source code

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Here is the source code for com.chinarewards.gwt.elt.client.widget.SortableHeader.java

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/*
 * 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.chinarewards.gwt.elt.client.widget;

import com.google.gwt.cell.client.ClickableTextCell;
import com.google.gwt.core.client.GWT;
import com.google.gwt.resources.client.ClientBundle;
import com.google.gwt.resources.client.ImageResource;
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.Header;
import com.google.gwt.user.client.ui.AbstractImagePrototype;

/**
 * A {@link Header} subclass that maintains sorting state and displays an icon
 * to indicate the sort direction.
 */
public class SortableHeader extends Header<String> {

    /**
     * Image resources.
     */
    public static interface Resources extends ClientBundle {

        ImageResource downArrow();

        ImageResource upArrow();
    }

    private static final Resources RESOURCES = GWT.create(Resources.class);
    private static final int IMAGE_WIDTH = 16;
    private static final String DOWN_ARROW = makeImage(RESOURCES.downArrow());
    private static final String UP_ARROW = makeImage(RESOURCES.upArrow());

    private static String makeImage(ImageResource resource) {
        AbstractImagePrototype proto = AbstractImagePrototype.create(resource);
        String html = proto.getHTML().replace("style='", "style='position:absolute;right:0px;top:0px;");
        return html;
    }

    private boolean reverseSort = false;
    private boolean sorted = false;
    private String text;

    public SortableHeader(String text) {
        super(new ClickableTextCell());
        this.text = text;
    }

    public boolean getReverseSort() {
        return reverseSort;
    }

    @Override
    public String getValue() {
        return text;
    }

    /* (non-Javadoc)
     * @see com.google.gwt.user.cellview.client.Header#render(com.google.gwt.safehtml.shared.SafeHtmlBuilder)
     */
    public void render(SafeHtmlBuilder sb) {
        if (sorted) {
            renderSortedHtml(IMAGE_WIDTH, reverseSort ? DOWN_ARROW : UP_ARROW, text, sb);
        } else {
            renderUnsortedHtml(IMAGE_WIDTH, text, sb);
        }
    }

    private void renderSortedHtml(int imageWidth, String arrow, String text, SafeHtmlBuilder sb) {

        sb.appendHtmlConstant("<div style=\"position:relative;cursor:hand;cursor:pointer;" + "padding-right:"
                + imageWidth + "px;\">");
        sb.appendHtmlConstant(arrow);
        sb.appendHtmlConstant("<div>");
        SafeHtml safeValue = SafeHtmlUtils.fromString(text);
        sb.append(safeValue);
        sb.appendHtmlConstant("</div></div>");

    }

    private void renderUnsortedHtml(int imageWidth, String text, SafeHtmlBuilder sb) {

        sb.appendHtmlConstant("<div style=\"position:relative;cursor:hand;cursor:pointer;" + "padding-right:"
                + imageWidth + "px;\">");
        sb.appendHtmlConstant("<div style=\"position:absolute;display:none;\"></div><div>");
        SafeHtml safeValue = SafeHtmlUtils.fromString(text);
        sb.append(safeValue).appendHtmlConstant("</div></div>");

    }

    public void setReverseSort(boolean reverseSort) {
        this.reverseSort = reverseSort;
    }

    public void setSorted(boolean sorted) {
        this.sorted = sorted;
    }

    public void toggleReverseSort() {
        this.reverseSort = !this.reverseSort;
    }
}