com.extjs.gxt.ui.client.dnd.StatusProxy.java Source code

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Here is the source code for com.extjs.gxt.ui.client.dnd.StatusProxy.java

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/*
 * Sencha GXT 2.3.1 - Sencha for GWT
 * Copyright(c) 2007-2013, Sencha, Inc.
 * licensing@sencha.com
 * 
 * http://www.sencha.com/products/gxt/license/
 */
package com.extjs.gxt.ui.client.dnd;

import com.extjs.gxt.ui.client.core.El;
import com.extjs.gxt.ui.client.widget.BoxComponent;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Element;

/**
 * A custom component used to display the status of the drag operation and
 * information about the data being dragged. The component is displayed next to
 * the cursor as the user drags data.
 */
public class StatusProxy extends BoxComponent {

    private static StatusProxy instance;

    /**
     * Returns the singleton instance.
     * 
     * @return the status proxy
     */
    public static StatusProxy get() {
        if (instance == null) {
            instance = new StatusProxy();
            instance.render(DOM.createDiv());
        }
        return instance;
    }

    private El ghost;
    private boolean status;
    private String dropStatus;
    protected String dropAllowed = "x-dd-drop-ok";
    protected String dropNotAllowed = "x-dd-drop-nodrop";

    StatusProxy() {
        setShadow(true);
    }

    /**
     * Updates the proxy's visual element to indicate the status of whether or not
     * drop is allowed over the current target element.
     * 
     * @param allowed true for the standard ok icon, false fo standard no icon
     */
    public void setStatus(boolean allowed) {
        setStatus(allowed, allowed ? dropAllowed : dropNotAllowed);
    }

    /**
     * Returns true if the drop is allowed.
     * 
     * @return the status
     */
    public boolean getStatus() {
        return status;
    }

    /**
     * Updates the proxy's visual element to indicate the status of whether or not
     * drop is allowed over the current target element.
     * 
     * @param cssClass cssClass the css class for the new drop status indicator
     *          image
     */
    public void setStatus(boolean status, String cssClass) {
        this.status = status;
        if (cssClass == null) {
            cssClass = dropNotAllowed;
        }
        if (dropStatus == null || !dropStatus.equals(cssClass)) {
            el().replaceStyleName(dropStatus, cssClass);
            dropStatus = cssClass;
        }
    }

    /**
     * Updates the contents of the ghost element.
     * 
     * @param element the new ghost content
     */
    public void update(Element element) {
        ghost.setInnerHtml(SafeHtmlUtils.EMPTY_SAFE_HTML);
        ghost.setStyleAttribute("margin", "");
        ghost.appendChild(element);
    }

    /**
     * Updates the contents of the ghost element.
     * 
     * @param html the html that will replace the current contents of the ghost
     *          element
     */
    public void update(SafeHtml html) {
        ghost.setInnerHtml(html);
    }

    @Override
    protected void onRender(Element target, int index) {
        setElement(DOM.createDiv(), target, index);
        setStyleName("x-dd-drag-proxy");

        el().createChild("<div class=x-dd-drop-icon></div>");
        ghost = el().createChild("<div class=x-dd-drag-ghost></div>");
        setStatus(false);
    }

}