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
$100.40
Apple Inc.
-0.13
MSFT
$45.10
Microsoft Corpora
-0.23
GOOG
$583.91
Google Inc.
-2.95

MacTech Search:
Community Search:

Software Updates via MacUpdate

Parallels Desktop 10.0 - Run Windows app...
Parallels Desktop is simply the world's bestselling, top-rated, and most trusted solution for running Windows applications on your Mac. With Parallels Desktop for Mac, you can seamlessly run both... Read more
Chromium 36.0.1985.143 - Fast and stable...
Chromium is an open-source browser project that aims to build a safer, faster, and more stable way for all Internet users to experience the web. FreeSMUG-Free OpenSource Mac User Group build is... Read more
Macgo Blu-ray Player 2.10.6.1691 - Blu-r...
Macgo Mac Blu-ray Player can bring you the most unforgettable Blu-ray experience on your Mac. Overview Macgo Mac Blu-ray Player can satisfy just about every need you could possibly have in a Blu-ray... Read more
Apple Motion 5.1.2 - Create and customiz...
Apple Motion is designed for video editors, Motion 5 lets you customize Final Cut Pro titles, transitions, and effects. Or create your own dazzling animations in 2D or 3D space, with real-time... Read more
A Better Finder Rename 9.39 - File, phot...
A Better Finder Rename is the most complete renaming solution available on the market today. That's why, since 1996, tens of thousands of hobbyists, professionals and businesses depend on A Better... Read more
PopChar X 6.6 - Floating window shows av...
PopChar X helps you get the most out of your font collection. With its crystal-clear interface, PopChar X provides a frustration-free way to access any font's special characters. Expanded... Read more
MacUpdate Desktop 6.0.2 - Install Mac ap...
MacUpdate Desktop 6 brings seamless 1-click installs and version updates to your Mac. With a free MacUpdate account and MacUpdate Desktop 6, Mac users can now install almost any Mac app on macupdate.... Read more
PDFpenPro 6.3.2 - Advanced PDF toolkit f...
PDFpenPro allows users to edit PDF's easily. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Create... Read more
PDFpen 6.3.2 - Edit and annotate PDFs wi...
PDFpen allows users to easily edit PDF's. Add text, images and signatures. Fill out PDF forms. Merge or split PDF documents. Reorder and delete pages. Even correct text and edit graphics! Features... Read more
OS X Yosemite 10.10 DP6 - Developer Prev...
Note: This is a Developer Preview. You must be a registered Apple Mac Developer to download this update. You can also sign up for the free OS X Beta Program to download and preview public beta... Read more

Latest Forum Discussions

See All

One Tap RPG Review
One Tap RPG Review By Campbell Bird on August 20th, 2014 Our Rating: :: DUNGEON SLIDERUniversal App - Designed for iPhone and iPad This casual arcade game introduces some very light rpg elements into its fantasy-themed pachinko... | Read more »
Goodbye Paywall – Table Tennis Touch Eli...
Goodbye Paywall – Table Tennis Touch Eliminates In-App Purchases Posted by Jessica Fisher on August 20th, 2014 [ permalink ] | Read more »
Go to Bed – An Interview With Touchfight...
Touchfight Games is an exciting new indie studio that was co-formed between game journalist and author Nathan Meunier, artist Leonard Kenyon, and programmer Jon Kenyon. Their debut game Go To Bed will be released this fall, and with all the... | Read more »
Assault Vector Review
Assault Vector Review By Rob Thomas on August 19th, 2014 Our Rating: :: SIMPLE STRATEGYUniversal App - Designed for iPhone and iPad While this hex-based warp ride is fine in theory, Assault Vector is a bit too simple to be... | Read more »
Tom Hanks’ Hanx Writer has Taken the App...
Tom Hanks’ Hanx Writer has Taken the App Store by Storm Posted by Jessica Fisher on August 19th, 2014 [ permalink ] iPad Only App - Designed for the iPad | Read more »
It Came from Canada: Galaxy Dash
With its use of well-established tropes like endless flying and sci-fi space shooting, the upcoming Galaxy Dash: Race to the Outer Run most likely won’t confound expectations. However, with its robust amount of opportunities for fun player... | Read more »
PromptSmart Review
PromptSmart Review By Jennifer Allen on August 19th, 2014 Our Rating: :: SNAPPY SPEECHGIVINGUniversal App - Designed for iPhone and iPad Offering you a teleprompter in your pocket, PromptSmart is immensely helpful for those who do... | Read more »
The Firm (Games)
The Firm 1 Device: iOS iPhone Category: Games Price: $.99, Version: 1 (iTunes) Description: *** LIMITED TIME LAUNCH OFFER -50% ! *** "The Firm is one of those games that looks so easy on the surface, but it's actually like a cerebral... | Read more »
They Need To Be Fed 3 (Games)
They Need To Be Fed 3 1.0.0 Device: iOS Universal Category: Games Price: $1.99, Version: 1.0.0 (iTunes) Description: 360 degree gravity platforming is back! Run, jump, collect, avoid enemies and feed yourself to the monster at the... | Read more »
Who Wore it Best? Phantom Flower vs. And...
Who Wore it Best? takes a break from all the bloodshed to check out two decidedly tranquil and nature-loving puzzles games: Phantom Flower and And Then it Rained. [ Who Wore it Best? Phantom Flower vs. And Then it Rained is a post from... | Read more »

Price Scanner via MacPrices.net

Best Buy’s College Student Deals: $100 off Ma...
Take an additional $100 off all MacBooks and iMacs, $50 off iPad Airs and iPad minis, at Best Buy Online with their College Students Deals Savings, valid through September 6th. Anyone with a valid .... Read more
MacBook Airs on sale for $100 off MSRP, free...
B&H Photo has three 2014 MacBook Airs on sale for $100 off MSRP. Shipping is free, and B&H charges NY sales tax only. They also include free copies of Parallels Desktop and LoJack for Laptops... Read more
Razer Taipan Mouse For Gamers And Non-Gamers...
If you’re a serious gamer on either Mac or Windows PCs, a serious gaming mouse is a necessity for first-tier performance. However, even if like me you’re not much of a gamer, there’s still a strong... Read more
15-inch 2.2GHz MacBook Pro on sale for $1899,...
Adorama has the new 15″ 2.2GHz Retina MacBook Pro on sale for $1899 including free shipping plus NY & NJ sales tax only. Their price is $100 off MSRP, and it’s the lowest price available for this... Read more
Mid-Size Tablet Shootout Posted: iPad mini wi...
I ‘m curious about how many iPads Apple is actually selling these days. It’s been widely rumored and anticipated that new models with A8 SoCs, 2 GB of RAM, 8 megapixel cameras, and fingerprint... Read more
The 15 Biggest iPad Air Problems And How To A...
What’s this? Fifteen “biggest” problems with the iPad Air? Does that mean there are a lot of smaller problems as well? Say it isn’t so! My old iPad 2 has manifested no hardware problems in three... Read more
TYLT Syncable-Duo, 2-in-1 USB Cable With Appl...
TYLT has introduced the Syncable-Duo, a universal cable solution for charging and syncing data to smartphones and tablets. The Syncable-Duo eliminates the need for multiple cables by incorporating... Read more
Save up to $140 off MSRP with Apple refurbish...
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
2.5GHz Mac mini on sale for $549, save $50
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
Chromebooks Are Actually Sometimes A Better C...
Mac360′s Kate MacKenzie notes that when Steve Jobs announced the post-PC era, he was assuming that the dominant post-PC device would be the iPad he was unveiling, or another Apple product like the... Read more

Jobs Board

Position Opening at *Apple* - Apple (United...
**Job Summary** Being a Business Manager at an Apple Store means you're the catalyst for businesses to discover and leverage the power, ease, and flexibility of Apple Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** At the Apple Store, you connect business professionals and entrepreneurs with the tools they need in order to put Apple solutions to work in their Read more
Project Manager / Business Analyst, WW *Appl...
…a senior project manager / business analyst to work within our Worldwide Apple Fulfillment Operations and the Business Process Re-engineering team. This role will work Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** As businesses discover the power of Apple computers and mobile devices, it's your job - as a Solutions Engineer - to show them how to introduce these Read more
Position Opening at *Apple* - Apple (United...
**Job Summary** As more and more people discover Apple , they visit our stores seeking ways to incorporate our products into their lives. It's your job, as a Store Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.