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.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

beaTunes 4.6.13 - Organize your music co...
beaTunes is a full-featured music player and organizational tool for music collections. How well organized is your music library? Are your artists always spelled the same way? Any R.E.M. vs REM?... Read more
Vienna 3.1.9 :e81515b: - RSS and Atom ne...
Vienna is a freeware and Open-Source RSS/Atom newsreader with article storage and management via a SQLite database, written in Objective-C and Cocoa, for the OS X operating system. It provides... Read more
iExplorer 4.0.12.0 - View and transfer f...
iExplorer is an iPhone browser for Mac lets you view the files on your iOS device. By using a drag and drop interface, you can quickly copy files and folders between your Mac and your iPhone or... Read more
OpenEmu 2.0.5 - Open Source game-emulati...
OpenEmu is about to change the world of video game emulation, one console at a time... For the first time, the 'It just works' philosophy now extends to open source video game emulation on the Mac.... Read more
TextSoap 8.3.3 - Automate tedious text d...
TextSoap can automatically remove unwanted characters, fix up messed up carriage returns, and do pretty much anything else that we can think of to text. Save time and effort. Be more productive. Stop... Read more
Apple iTunes 12.6 - Play Apple Music and...
Apple iTunes lets you organize and stream Apple Music, download and watch video and listen to Podcasts. It can automatically download new music, app, and book purchases across all your devices and... Read more
Airmail 3.2.4 - Powerful, minimal email...
Airmail is an mail client with fast performance and intuitive interaction. Support for iCloud, MS Exchange, Gmail, Google Apps, IMAP, POP3, Yahoo!, AOL, Outlook.com, Live.com. Airmail was designed... Read more
MacPilot 9.0.6 - Enable over 1,200 hidde...
MacPilot gives you the power of UNIX and the simplicity of Macintosh, which means a phenomenal amount of untapped power in your hands! Use MacPilot to unlock over 1,200 features, and access them all... Read more
Jamf Pro 9.98 - Powerful sysadmin/enterp...
Jamf Pro (formerly Casper Suite) is the EMM tool that delights IT pros and the users they support by delivering on the promise of unified endpoint management for Apple devices. At Jamf, connecting... Read more
PopChar 7.7 - $16.99 (51% off)
PopChar helps you get the most out of your font collection. With its crystal-clear interface, PopChar provides a frustration-free way to access any font's special characters. Features Expanded... Read more

Leap to victory in Nexx Studios new plat...
You’re always a hop, skip, and a jump away from a fiery death in Temple Jump, a new platformer-cum-endless runner from Nexx Studio. It’s out now on both iOS and Android if you’re an adventurer seeking treasure in a crumbling, pixel-laden temple. | Read more »
Failbetter Games details changes coming...
Sunless Sea, Failbetter Games' dark and gloomy sea explorer, sets sail for the iPad tomorrow. Ahead of the game's launch, Failbetter took to Twitter to discuss what will be different in the mobile version of the game. Many of the changes make... | Read more »
Splish, splash! The Pokémon GO Water Fes...
Niantic is back with a new festival for dedicated Pokémon GO collectors. The Water Festival officially kicks off today at 1 P.M. PDT and runs through March 29. Magikarp, Squirtle, Totodile, and their assorted evolved forms will be appearing at... | Read more »
Death Road to Canada (Games)
Death Road to Canada 1.0 Device: iOS Universal Category: Games Price: $7.99, Version: 1.0 (iTunes) Description: Get it now at the low launch price! Price will go up a dollar every major update. Update news at the bottom of this... | Read more »
Bean's Quest Beginner's Guide:...
Bean's Quest is a new take on both the classic platformer and the endless runner, and it's free on the App Store for the time being. Instead of running constantly, you can't stop jumping. That adds a surprising new level of challenge to the game... | Read more »
How to rake in the cash in Bit City
Our last Bit City guide covered the basics. Now it's time to get into some of the more advanced techniques. In the later cities, cash flow becomes much more difficult, so you'll want to develop some strategies if you want to complete each level.... | Read more »
PixelTerra (Games)
PixelTerra 1.1.1 Device: iOS Universal Category: Games Price: $.99, Version: 1.1.1 (iTunes) Description: The world of PixelTerra is quite dangerous so you need to build a shelter, find some food supply and get ready to protect... | Read more »
Tokaido™ (Games)
Tokaido™ 1.0 Device: iOS Universal Category: Games Price: $6.99, Version: 1.0 (iTunes) Description: Discover the digital adaptation of Tokaido, the boardgame phenomenon that has already sold more than 250,000 copies worldwide, and... | Read more »
Card Thief (Games)
Card Thief 1.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0 (iTunes) Description: Card Thief is a solitaire style stealth game played with a deck of cards. In Card Thief you move through a deck of cards as a... | Read more »
Smilegate’s crafting battler Super Tank...
Super Tank Rumbleputs you in the seat of your very own, handcrafted tank. You can choose from over 100 different parts to create your Super Tank before taking it out to wreak havoc on your opponents in glorious PVP combat. Now, Smilegate is upping... | Read more »

Price Scanner via MacPrices.net

Save $230 with Apple Certified Refurbished 13...
Apple is now offering Certified Refurbished 2016 13″ 2.0GHz non-Touch Bar MacBook Pros for $230 off original MSRP. An Apple one-year warranty is included with each model, and shipping is free: - 13″... Read more
Apple price trackers, updated continuously
Scan our Apple Price Trackers for the latest information on sales, bundles, and availability on systems from Apple’s authorized internet/catalog resellers. We update the trackers continuously: - 15″... Read more
13-inch Touch Bar MacBook Pros on sale for up...
B&H Photo has the Apple 13″ Touch Bar MacBook Pros in stock today and on sale for up to $150 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 13″ 2.9GHz/512GB Touch Bar... Read more
Today only! 15-inch 2.7GHz Space Gray Touch B...
B&H Photo has the new 2016 15″ 2.7GHz Space Gray Apple Touch Bar MacBook Pro in stock today and on sale for $300 off MSRP for today only. Shipping is free, and B&H charges NY sales tax only... Read more
New $329 iPad A Fabulous Value; 10.5-Inch iPa...
Part of the iPad upgrade/new model puzzle is now in place. Yesterday, as KGI Securities financial services group analyst Ming-Chi Kuo last summer predicted they would, Apple released a new low-cost 9... Read more
New 9.7-Inch iPad Features All Of The Fun...
Apple today updated its most popular-sized iPad, featuring a brighter 9.7-inch Retina display and best-in-class performance at its most affordable price ever, starting at $329 (US) with 32GB of... Read more
Apple Introduces iPhone 7 and iPhone 7 Plus (...
Apple today announced iPhone 7 and iPhone 7 Plus (PRODUCT)RED Special Edition in a vibrant red matte aluminum finish, in recognition of more than 10 years of partnership between Apple and (RED). This... Read more
Apple now offering Certified Refurbished 15-i...
Apple is now offering Certified Refurbished 2016 15″ Touch Bar MacBook Pros for $360-$420 off original MSRP. An Apple one-year warranty is included with each model, and shipping is free: - 15″ 2.6GHz... Read more
Apple Introduces Clips: A Free Innovative Way...
Apple today introduced Clips, a new app that makes it quick and fun for anyone to create expressive videos on iPhone and iPad. The app features a unique design for combining video clips, photos and... Read more
Urban Armor Gear Unveils Case For 4th Generat...
Orange County, California based Urban Armor Gear (UAG), designers of rugged, lightweight protective cases for phones, tablets and laptops, has released its latest drop-tested cases for Apple’s 4th... Read more

Jobs Board

*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
Fulltime aan de slag als shopmanager in een h...
Ben jij helemaal gek van Apple -producten en vind je het helemaal super om fulltime shopmanager te zijn in een jonge en hippe elektronicazaak? Wil jij werken in Read more
Starte Dein Karriere-Abenteuer in den Hauptst...
…mehrsprachigen Teams betreust Du Kunden von bekannten globale Marken wie Apple , Mercedes, Facebook, Expedia, und vielen anderen! Funktion Du wolltest schon Read more
Starte Dein Karriere-Abenteuer in den Hauptst...
…mehrsprachigen Teams betreust Du Kunden von bekannten globale Marken wie Apple , Mercedes, Facebook, Expedia, und vielen anderen! Funktion Du wolltest schon Read more
*Apple* Retail - Multiple Positions - Apple,...
Job Description: Sales Specialist - Retail Customer Service and Sales Transform Apple Store visitors into loyal Apple customers. When customers enter the store, Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.