/*
* DoubleClickState.java
*
* Copyright (C) 2009-12 by RStudio, Inc.
*
* Unless you have received this program directly from RStudio pursuant
* to the terms of a commercial license agreement with RStudio, then
* this program is licensed to you under the terms of version 3 of the
* GNU Affero General Public License. This program is distributed WITHOUT
* ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
* AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
*
*/
package org.rstudio.core.client.widget;
import com.google.gwt.dom.client.NativeEvent;
import org.rstudio.core.client.Point;
import java.util.Date;
/**
* Helper class to make it easy to detect double-clicks in click handlers.
*/
public class DoubleClickState
{
public boolean checkForDoubleClick(NativeEvent event)
{
if (event.getButton() != NativeEvent.BUTTON_LEFT)
{
lastClickPos_ = null;
lastClickTime_ = null;
return false;
}
Date now = new Date();
if (!isDoubleClick(event, now))
{
lastClickPos_ = new Point(event.getClientX(), event.getClientY());
lastClickTime_ = now;
return false;
}
else
{
// Prevent three clicks from generating two double clicks
lastClickPos_ = null;
lastClickTime_ = null;
return true;
}
}
private boolean isDoubleClick(NativeEvent event, Date now)
{
if (lastClickPos_ == null || lastClickTime_ == null)
return false;
long millisSinceLast = now.getTime() - lastClickTime_.getTime();
if (millisSinceLast > 500)
return false;
if (Math.abs(lastClickPos_.x - event.getClientX()) > 3
|| Math.abs(lastClickPos_.y - event.getClientY()) > 3)
return false;
return true;
}
private Point lastClickPos_;
private Date lastClickTime_;
}