TweetFollow Us on Twitter

A Dashboard Widget that supports Drag-and-Drop

Volume Number: 24
Issue Number: 12
Column Tag: Dashboard Widgets

A Dashboard Widget that supports Drag-and-Drop

How to Drag-and-Drop files and directories between Dashboard Widgets and/or Finder

By Mihalis Tsoukalos

Introduction

This article is going to show you how to program a well-known Drag-and-Drop technique for Dashboard Widgets.

The idea of the presented Widget is pretty simple. You Drag-and-Drop either a file or a directory from the Finder to the Dashboard Widget. The Widget will then show you the full path of the file or the directory.

The Widget is called DaD and its output can be seen in figure 1.


Figure 1: The DaD Dashboard Widget

The files that compose the Widget

Figure 2 shows the files of the Widget as well as their sizes (in bytes).


Figure 2: The directory structure of the DaD Widget

If you have already read the previous articles about Dashboard Widgets that I have written for MacTech, you should know by now about the Default.png and Icon.png graphic files. If not, please check the Bibliography and References section of this article.

The DaD.html file

The contents of the DaD.html file are the following:

<!–
File: DaD.html
Programmer: Mihalis Tsoukalos
Date: Tuesday 06 November 2007
–>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
        "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
<!– The CSS file for this widget –>
<!– This is a very simple CSS file –>
<style type="text/css">
   @import "DaD.css";
</style>
<!– The JavaScript code for this Widget –>
<script type='text/javascript' src='DaD.js' charset='utf-8'/>
</head>
   <body ondragenter='dragenter(event);' ondragover='dragover(event);' 
           ondrop='dragdrop(event);' ondragleave='dragleave(event);'>
   <img src="default.png" >
   <div class="Data">
      <div class="PATHoutput">
         <div id="myText">Drop the file or the directory HERE!</div>
         <div id="PATH"></div>
      </div>
   </div>
</body>
</html>

The DaD.html HTML file encapsulates the JavaScript and the CSS files of the Widget as usual but it also declares four events using the following HTML code:

<body ondragenter='dragenter(event);' ondragover='dragover(event);' 
           ondrop='dragdrop(event);' ondragleave='dragleave(event);'>

The DaD.js JavaScript file

The following JavaScript code is used in the DaD.js file:

/*
File: DaD.js
Programmer: Mihalis Tsoukalos
Date: Thursday 08 November 2007
*/
// You must have an event handler for every handler
// that you are going to support.
// This Widget only supports the dragdrop event.
function dragdrop (event)
{
   var uri = null;
   try {
       uri = event.dataTransfer.getData("text/uri-list");
   } catch (ex)
   {
   }
   // if the acquisition is successful:
   if (uri)
   {
      // Write some text to the output
      document.getElementById("myText").innerText = "The full path is:";
      // And display the file's PATH
      document.getElementById("PATH").innerText = uri;
   }
   event.stopPropagation();
   event.preventDefault();
}
// Although the following events are not supported
// their handlers must be present and do nothing.
function dragenter(event)
{
   event.stopPropagation();
   event.preventDefault();
}
function dragover(event)
{
   event.stopPropagation();
   event.preventDefault();
}
function dragleave(event)
{
   event.stopPropagation();
   event.preventDefault();
}

The DaD.css file

The DaD.css file contains the following CSS code:

/*
File: DaD.css
Programmer: Mihalis Tsoukalos
Date: Tuesday 06 November 2007
*/
body
{
   margin: 0;
}
#myText
{
   font-weight: bold;
   color: white; 
   padding-top: 4px;
   padding-bottom: 2px;
   text-align: center;
}
#PATH
{
   font: 12px "Lucida Grande";
   font-weight: bold;
   color: white;
   word-wrap: break-word;
   padding-top: 2px;
   padding-bottom: 4px;
}
.Data
{
   opacity: 1.0;
   position: absolute;
   top: 30px;
   left: 15px;
}
.PATHoutput
{
   color: grey;
   padding-right: 8px;
   padding-left: 8px;
   width: 140px;
}

The CSS file of the Widget is simple and easily understood.

The Info.plist file of the Widget

The XML version of the Info.plist file is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" 
        "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
   <key>AllowFileAccessOutsideOfWidget</key>
   <true/>
   <key>CFBundleDisplayName</key>
   <string>DaD</string>
   <key>CFBundleIdentifier</key>
   <string>com.mtsouk.widget.DaD</string>
   <key>CFBundleName</key>
   <string>Drag and Drop Widget</string>
   <key>CFBundleShortVersionString</key>
   <string>1.1</string>
   <key>CFBundleVersion</key>
   <string>1.1</string>
   <key>CloseBoxInsetX</key>
   <integer>45</integer>
   <key>CloseBoxInsetY</key>
   <integer>35</integer>
   <key>MainHTML</key>
   <string>DaD.html</string>
</dict>
</plist>

As you can see you have to set the AllowFileAccessOutsideOfWidget key to true in order to be able to access files or directories that reside outside the Widget directory. Please note that this can be a security risk.

Explaining the Technique

First, I have to tell you that although the dragover, dragenter and dragleave handlers are not doing anything useful, they must be present in the DaD.js JavaScript file. The only handler that in fact does a useful thing is the dragdrop handler. The dragdrop handler reads the file or the directory name using the event.dataTransfer.getData("text/uri-list") code. Then the data is written to the Widget area and the Widget is ready to accept other input using drag and drop.

As you can see if you try it, you cannot copy the output of the DaD Widget and use it somewhere else. This is going to be corrected in the next article.

Conclusions

The presented Widget implements "dragging and dropping" between the Finder and the Dashboard. The presented technique is not very difficult, yet it is very valuable - especially when combined with the "Copy and Paste" practice.

Disclaimer: Please note that the presented Widget is based on the Dropper example Widget from Apple. The Dropper Widget is available if you install the Tiger Developer Tools but it is not available in a Leopard Mac OS X system.

Bibliography and References

Dashboard sample code (from Apple developer site): http://developer.apple.com/samplecode/AppleApplications/idxDashboard-date.html

Apple Dashboard Page: http://developer.apple.com/appleapplications/dashboard/

Debugging Dashboard Widgets (from Apple developer site): http://developer.apple.com/technotes/tn2005/tn2139.html

"Programming Dashboard Widgets" eBook by Mihalis Tsoukalos. You can find more information about the book at http://widgetbook.blogspot.com/. You can buy it at: http://store.kagi.com/cgi-bin/store.cgi?storeID=6FFME_LIVE

"Creating Widgets with Dashcode", Mihalis Tsoukalos, August 2008, MacTech


Mihalis Tsoukalos lives in Greece with his wife Eugenia and enjoys digital photography and writing articles. He is the author of the "Programming Dashboard Widgets" eBook. You can reach him at tsoukalos@sch.gr.

 
AAPL
$95.94
Apple Inc.
-2.21
MSFT
$43.40
Microsoft Corpora
-0.18
GOOG
$575.68
Google Inc.
-11.75

MacTech Search:
Community Search:

Software Updates via MacUpdate

OmniPlan 2.3.6 - Robust project manageme...
With OmniPlan, you can create logical, manageable project plans with Gantt charts, schedules, summaries, milestones, and critical paths. Break down the tasks needed to make your project a success,... Read more
Command-C 1.1.1 - Clipboard sharing tool...
Command-C is a revolutionary app which makes easy to share your clipboard between iOS and OS X using your local WiFi network, even if the app is not currently opened. Copy anything (text, pictures,... Read more
Knock 1.1.7 - Unlock your Mac by knockin...
Knock is a faster, safer way to sign in. You keep your iPhone with you all the time. Now you can use it as a password. You never have to open the app -- just knock on your phone twice, even when it's... Read more
Mellel 3.3.6 - Powerful word processor w...
Mellel is the leading word processor for OS X and has been widely considered the industry standard since its inception. Mellel focuses on writers and scholars for technical writing and multilingual... Read more
LibreOffice 4.3.0.4 - Free Open Source o...
LibreOffice is an office suite (word processor, spreadsheet, presentations, drawing tool) compatible with other major office suites. The Document Foundation is coordinating development and... Read more
Freeway Pro 7.0 - Drag-and-drop Web desi...
Freeway Pro lets you build websites with speed and precision... without writing a line of code! With it's user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of... Read more
Drive Genius 3.2.4 - Powerful system uti...
Drive Genius is an OS X utility designed to provide unsurpassed storage management. Featuring an easy-to-use interface, Drive Genius is packed with powerful tools such as a drive optimizer, a... Read more
Vitamin-R 2.15 - Personal productivity t...
Vitamin-R creates the optimal conditions for your brain to work at its best by structuring your work into short bursts of distraction-free, highly focused activity alternating with opportunities for... Read more
Toast Titanium 12.0 - The ultimate media...
Toast Titanium goes way beyond the very basic burning in the Mac OS and iLife software, and sets the standard for burning CDs, DVDs, and now Blu-ray discs on the Mac. Create superior sounding audio... Read more
OS X Yosemite Wallpaper 1.0 - Desktop im...
OS X Yosemite Wallpaper is the gorgeous new background image for Apple's upcoming OS X 10.10 Yosemite. This wallpaper is available for all screen resolutions with a source file that measures 5,418... Read more

Latest Forum Discussions

See All

Hexiled Review
Hexiled Review By Rob Thomas on July 31st, 2014 Our Rating: :: HEX SELLSUniversal App - Designed for iPhone and iPad In space, no one can hear you… spell? Hexiled is a neat concept for a word scramble puzzle, but it doesn’t go too... | Read more »
Despicable Me: Minion Rush is One Year O...
Despicable Me: Minion Rush is One Year Old, Gets its Biggest Update Yet Posted by Jennifer Allen on July 31st, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Plants vs. Zombies 2 Enters the Second H...
Plants vs. Zombies 2 Enters the Second Half of the Dark Ages Posted by Ellis Spice on July 31st, 2014 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Why Does It Spin? (Games)
Why Does It Spin? 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: THERE'S ONLY ONE RULE: DON'T TOUCH THE WALLS! Do you think you're able to follow this simple rule even if you would have to... | Read more »
Ice Wings Plus (Games)
Ice Wings Plus 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: THE GREAT ENDLESS RUNNER OF COMBAT JETS IS BACK !! With more than 680.000 downloads in the App Store, Ice Wings: Skies of Steel... | Read more »
Murl the Squirrel (Games)
Murl the Squirrel 1.0 Device: iOS Universal Category: Games Price: $.99, Version: 1.0 (iTunes) Description: Meet Murl. He is teased by a group of flying squirrels because he can't fly. Determined to show them he's can fly, he meets... | Read more »
Celleste (Games)
Celleste 0.1 Device: iOS Universal Category: Games Price: $2.99, Version: 0.1 (iTunes) Description: Lots of cute action with amazing 3D graphics and a new type of gameplay! Take control over the forces of the universe to help a group... | Read more »
Super Heavy Sword (Games)
Super Heavy Sword 0.0.1 Device: iOS Universal Category: Games Price: $.99, Version: 0.0.1 (iTunes) Description: Get Ready to Get HEAVY! Monster Robot Studios presents SUPER Heavy Sword! The sequel to the smash hit HEAVY sword which... | Read more »
Angels In The Sky (Games)
Angels In The Sky 1.00 Device: iOS Universal Category: Games Price: $6.99, Version: 1.00 (iTunes) Description: - A.I.S will only run smoothly on iPhone 5s. It's NOT compatible with iPad, iPhone 5 or earlier devices.- In order to... | Read more »
80 Days (Games)
80 Days 1.0.2 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0.2 (iTunes) Description: 1872, with a steampunk twist. Phileas Fogg has wagered he can circumnavigate the world in just eighty days. Choose your own route... | Read more »

Price Scanner via MacPrices.net

iPad Cannibalization Threat “Overblown”
Seeking Alpha’s Kevin Greenhalgh observes that while many commentators think Apple’s forthcoming 5.5-inch panel iPhone 6 will cannibalize iPad sales, in his estimation, these concerns are being... Read more
Primate Labs Releases July 2014 MacBook Pro P...
Primate Labs’ John Poole has posted Geekbench 3 results for most of the new MacBook Pro models that Apple released on Tuesday. Poole observes that overall performance improvements for the new MacBook... Read more
Apple Re-Releases Bugfixed MacBook Air EFI Fi...
Apple has posted a bugfixed version EFI Firmware Update 2.9 a for MacBook Air (Mid 2011) models. The update addresses an issue where systems may take longer to wake from sleep than expected, and... Read more
Save $50 on the 2.5GHz Mac mini, plus free sh...
B&H Photo has the 2.5GHz Mac mini on sale for $549.99 including free shipping. That’s $50 off MSRP, and B&H will also include a free copy of Parallels Desktop software. NY sales tax only. Read more
Save up to $140 on an iPad Air with Apple ref...
Apple is offering Certified Refurbished iPad Airs for up to $140 off MSRP. Apple’s one-year warranty is included with each model, and shipping is free. Stock tends to come and go with some of these... Read more
$250 price drop on leftover 15-inch Retina Ma...
B&H Photo has dropped prices on 2013 15″ Retina MacBook Pros by $250 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.3GHz Retina MacBook Pro: $2249, $250 off... Read more
More iPad Upgrade Musings – The ‘Book Mystiqu...
Much discussed recently, what with Apple reporting iPad sales shrinkage over two consecutive quarters, is that it had apparently been widely assumed that tablet users would follow a two-year hardware... Read more
13-inch 2.5GHz MacBook Pro on sale for $999,...
Best Buy has the 13″ 2.5GHz MacBook Pro available for $999.99 on their online store. Choose free shipping or free instant local store pickup (if available). Their price is $100 off MSRP. Price is... Read more
Save up to $300 on an iMac with Apple refurbi...
The Apple Store has Apple Certified Refurbished iMacs available for up to $300 off the cost of new models. Apple’s one-year warranty is standard, and shipping is free. These are the best prices on... Read more
WaterField Unveils 15″ Outback Solo & 13″...
Hard on the heels of Apple’s refreshed MacBook Pro Retina laptops announcement, WaterField Designs has unveiled a 15-inch version of the waxed-canvas and leather Outback Solo and a 13-inch version of... Read more

Jobs Board

Sr. Product Leader, *Apple* Store Apps - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
Sr Software Lead Engineer, *Apple* Online S...
Sr Software Lead Engineer, Apple Online Store Publishing Systems Keywords: Company: Apple Job Code: E3PCAK8MgYYkw Location (City or ZIP): Santa Clara Status: Full Read more
*Apple* Solutions Consultant (ASC) - Apple (...
**Job Summary** The ASC is an Apple employee who serves as an Apple brand ambassador and influencer in a Reseller's store. The ASC's role is to grow Apple Read more
Sr. Product Leader, *Apple* Store Apps - Ap...
**Job Summary** Imagine what you could do here. At Apple , great ideas have a way of becoming great products, services, and customer experiences very quickly. Bring Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.