TweetFollow Us on Twitter

A Dashboard Widget that Reads and Saves its Preferences

Volume Number: 24
Issue Number: 10
Column Tag: Dashboard Widgets

A Dashboard Widget that Reads and Saves its Preferences

Create a Dashboard Widget that can save and read data after restarting it.

by Mihalis Tsoukalos

Introduction

In this article I am going to illustrate how to create a Dashboard Widget that saves its preferences. After saving the preferences, you will learn how to read and use the saved information and display the selected data in the front side of the Widget. The name of the Widget is "Save Prefs".

The files that compose the Widget

Figure 1 shows the files of the Widget as well as their sizes (in bytes).


Figure 1: The files that compose the "Save Prefs" Widget.

As you can understand by looking at Figure 1, the "Save Prefs" Widget is relatively simple. You should notice that it has a directory -the AppleClasses directory- that contains three JavaScript files. Apple provides the contents of the AppleClasses directory and the only thing that you should do is to copy the three JavaScript files inside your Widget's directory.

Also, as you will see in the next section, you will have to include them in the main HTML file of your Widget. Source code for this project can be downloaded from ftp.mactech.com/src/mactech/volume24_2008/24.10.sit. The source archive contains the following files:

SavePrefs.html file

SavePrefs.js file

SavePrefs.css

Info.plist

You may think that the SavePrefs.js JavaScript file contains a lot of code but most of the code is typical when creating a Dashboard Widget. The showPrefs() and hidePrefs() functions are used for watching and hiding the back side of the Widget and you usually have to copy and paste their definitions to your new Widgets.

The SavePrefs.css file

The CSS file looks pretty simple. Nevertheless, if you make small mistakes to the CSS code the Widget may misbehave very badly! I am saying this because I had some problems with the #OptionPopup declaration. Due to my wrong declarations the option list was displayed outside of the Widget area and I could not see it at all!

The Info.plist file

The Info.plist file is pretty simple and 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>BackwardsCompatibleClassLookup</key>
<true/>
<key>CFBundleDisplayName</key>
<string>Save Prefs</string>
<key>CFBundleIdentifier</key>
<string>com.mtsouk.widget.saveprefs</string>
<key>CFBundleName</key>
<string>Save Prefs</string>
<key>CFBundleShortVersionString</key>
<string>1.0</string>
<key>CFBundleVersion</key>
<string>1.0</string>
<key>CloseBoxInsetX</key>
<integer>14</integer>
<key>CloseBoxInsetY</key>
<integer>16</integer>
<key>MainHTML</key>
<string>SavePrefs.html</string>
</dict>
</plist>

Explaining the Technique

The presented technique uses the following two JavaScript methods:

  • widget.preferenceForKey(keyName): This method tries to read the value of a key, if the value is already saved.
  • widget.setPreferenceForKey(value, keyName): This method sets the value of a key. The Dashboard Reference suggests that you should pass null in order to delete an existing key.

Apple suggests that you utilize the widget.preferenceForKey(keyName) function using the following practice:

   if(window.widget)
   {
       var optionString = widget.preferenceForKey("optionString");
       if (optionString && optionString.length > 0)
       {
           optionText.innerText = optionString;
       }
   }

Similarly, Apple suggests that you use the widget.setPreferenceForKey(value, keyName) function as follows:

   if(window.widget)
   {
       widget.setPreferenceForKey("Hello MacTech!","optionString");
   }

A word of advice: The described method stores strings without any encryption. It is therefore not a secure way to store your sensitive information.

The following lines of JavaScript code declare two global variables, called glassDoneButton and whiteInfoButton, respectively. Each of the two variables holds one button. The first declaration creates the done button whereas the second declaration creates that little info (i) button that you frequently see in Widgets.

   var glassDoneButton;
   var whiteInfoButton;

The following JavaScript code implements the two button definitions:

   glassDoneButton = new AppleGlassButton(document.getElementById("doneButton"),
            "Done", hidePrefs);
   whiteInfoButton = new AppleInfoButton(document.getElementById("infoButton"),
            document.getElementById("front"), "white", "white", showPrefs);

The following command line output text explains where Dashboard keeps the Widget stored information using the described method:

mtsouk$ ll ~/Library/Preferences/widget-com.mtsouk.widget.saveprefs.plist
-rw————
    1 mtsouk   mtsouk         98 May 18 22:13
    /Users/mtsouk/Library/Preferences/widget-com.mtsouk.widget.saveprefs.plist
mtsouk$

The contents of the widget-com.mtsouk.widget.save-prefs.plist file are the following:

   <?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
   <key>OptionString</key>
   <string>Option 4</string>
</dict>
</plist>


Figure 2: The final look of the presented Widget (both sides).

A word of advice: You can now understand why it is extremely important to have a uniquely defined CFBundleIdentifier key for every Widget that you create or use. The above plist file that stores the Widget preferences uses the CFBundleIdentifier value as a part of its filename. It is also important to have a UNIQUE CFBundleName key because if you try to install a Widget with the same CFBundleName key, Dashboard will ask you if you want to replace the existing Widget (the other, different Widget with the same CFBundleName name)!!

Conclusions

This article presents an advanced technique that lets you store and retrieve your Dashboard Widget preferences or any other data you like. The presented Widget uses the back side for selecting the desired preference and its front side for displaying it but you can choose to implement it any way you want.

Bibliography and References

Introduction to Dashboard Programming Topics: http://developer.apple.com/documentation/AppleApplications/Conceptual/Dashboard_ProgTopics/Introduction/Introduction.html

Introduction to Dashboard Tutorial: http://developer.apple.com/documentation/AppleApplications/Conceptual/Dashboard_Tutorial/Introduction/chapter_1_section_1.html

Developing Dashboard Widgets: http://developer.apple.com/macosx/dashboard.html

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

Debugging Dashboard Widgets: http://developer.apple.com/technotes/tn2005/tn2139.html

Dashboard Sample Code: http://developer.apple.com/samplecode/AppleApplications/idxDashboard-date.html#//apple_ref/doc/uid/TP30000925-TP30000418-TP40001366

Disclaimer: The presented Widget code is a modified version of the "GoodBye" Widget provided by Apple and located on your Tiger machine (but not in Mac OS X 10.5), inside the "/Developer/Examples/Dashboard/GoodbyeWorld/3-SavingPreferences" folder. The "Save Prefs" Widget that is presented in this article has four options and, as you saw, it is a little bit more complicated than the "GoodBye" Apple Widget.


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

Dash 3.0.2 - Instant search and offline...
Dash is an API Documentation Browser and Code Snippet Manager. Dash helps you store snippets of code, as well as instantly search and browse documentation for almost any API you might use (for a full... Read more
FontExplorer X Pro 5.0 - Font management...
FontExplorer X Pro is optimized for professional use; it's the solution that gives you the power you need to manage all your fonts. Now you can more easily manage, activate and organize your... Read more
Typinator 6.6 - Speedy and reliable text...
Typinator turbo-charges your typing productivity. Type a little. Typinator does the rest. We've all faced projects that require repetitive typing tasks. With Typinator, you can store commonly used... Read more
Arq 4.12.1 - Online backup to Google Dri...
Arq is super-easy online backup for the Mac. Back up to your own Google Drive storage (15GB free storage), your own Amazon Glacier ($.01/GB per month storage) or S3, or any SFTP server. Arq backs up... Read more
Gutenprint 5.2.11-pre1 - Quality drivers...
Gutenprint is a suite of printer drivers that may be used with most common UNIX print spooling systems, including CUPS, lpr, LPRng, or others. Gutenprint currently supports over 2000 printer models.... Read more
Dropbox 3.6.8 - Cloud backup and synchro...
Dropbox is an application that creates a special Finder folder that automatically syncs online and between your computers. It allows you to both backup files and keep them up-to-date between systems... Read more
Evernote 6.0.15 - Create searchable note...
Evernote allows you to easily capture information in any environment using whatever device or platform you find most convenient, and makes this information accessible and searchable at anytime, from... Read more
MacUpdate Desktop 6.0.7 - Search and ins...
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
Freeway Pro 7.0.4 - Drag-and-drop Web de...
Freeway Pro lets you design and build sophisticated responsive websites code free. With its user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of your dreams. Add... Read more
VueScan 9.5.18 - Scanner software with a...
VueScan is a scanning program that works with most high-quality flatbed and film scanners to produce scans that have excellent color fidelity and color balance. VueScan is easy to use, and has... Read more

This Week at 148Apps:June 22-26, 2015
June's Summer Journey Continues With 148Apps How do you know what apps are worth your time and money? Just look to the review team at 148Apps. We sort through the chaos and find the apps you're looking for. The ones we love become Editor’s Choice,... | Read more »
LEGO® Minifigures Online (Games)
LEGO® Minifigures Online 1.0.1 Device: iOS iPhone Category: Games Price: $4.99, Version: 1.0.1 (iTunes) Description: | Read more »
World of Tanks Blitz celebrates its firs...
Today marks the first anniversary of the launch of World of Tanks Blitz, the mobile version of the PC tank battler, World of Tanks. World of Tanks Blitz launched on iOS and Android on June 26th last year and to celebrate, Wargaming is giving all... | Read more »
Heroes and Castles 2 Has its Own Standal...
Heroes and Castles 2 is a third-person castle defense game from the same team behind Block Fortress and Bug Heroes. It's cool, it's fun, and now it has its very own free version. [Read more] | Read more »
Formula Cartoon All-Stars Lets You Race...
Ever want to pit your favorite characters from shows like Steven Universe, Adventure Time, and Regular Show against each other in a not quite death race? Well once upon a time you could, but Formula All Stars Touch N' Go doesn't exist anymore. Hope... | Read more »
Retype - Typography Photo Editor (Photo...
Retype - Typography Photo Editor 1.0 Device: iOS Universal Category: Photography Price: $2.99, Version: 1.0 (iTunes) Description: Retype is built out of passion for great typography and it's all about adding text to photo with style... | Read more »
Hungry Shark Evolution Celebrates Shark...
Shark Week is almost here, as is Independence Day, so naturally Hungry Shark Evolution is going to get in on the action. Yes, even the fireworks. [Read more] | Read more »
The New Trivia Crack Will Feature a Musi...
It's official: iHeartMedia (you may know them from iHeartRadio) will be in charge of providing music-related questions for Trivia Crack's upcoming sequel. Also Trivia Crack is getting a sequel. [Read more] | Read more »
Toca Life: City (Education)
Toca Life: City 1.0 Device: iOS Universal Category: Education Price: $2.99, Version: 1.0 (iTunes) Description: Welcome to Toca Life: City, a metropolis filled with everyday fun! Customize characters, explore exciting locations and... | Read more »
Ironkill's Big New Update is Big an...
The other popular robot fighting game on the App Store, Ironkill, has received a pretty substantial update today. We're talking new bots, new rewards, graphical tweaks; the works. [Read more] | Read more »

Price Scanner via MacPrices.net

MacBook Airs on sale for up to $75 off MSRP
Save up to $75 on the purchase of a new 2015 13″ or 11″ 1.6GHz MacBook Air at the following resellers. Shipping is free with each model: 11" 128GB MSRP $899 11" 256GB... Read more
Apple’s Education discount saves up to $300 o...
Purchase a new Mac or iPad at The Apple Store for Education and take up to $300 off MSRP. All teachers, students, and staff of any educational institution qualify for the discount. Shipping is free,... Read more
Save up to $600 with Apple refurbished Mac Pr...
The Apple Store has Apple Certified Refurbished Mac Pros available for up to $600 off the cost of new models. An Apple one-year warranty is included with each Mac Pro, and shipping is free. The... Read more
Mac Pros on sale for up to $260 off MSRP
B&H Photo has Mac Pros on sale for up to $260 off MSRP. Shipping is free, and B&H charges sales tax in NY only: - 3.7GHz 4-core Mac Pro: $2799, $200 off MSRP - 3.5GHz 6-core Mac Pro: $3719.99... Read more
Save up to $400 on 2014 15-inch Retina MacBoo...
B&H Photo has previous-generation 2014 15″ Retina MacBook Pros on sale for up to $400 off original MSRP. Shipping is free, and B&H charges NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro... Read more
15-inch Retina MacBook Pros on sale for up to...
B&H Photo has new 2015 15″ Retina MacBook Pros on sale for up to $125 off MSRP including free shipping plus NY sales tax only: - 15″ 2.2GHz Retina MacBook Pro: $1899.99 $100 off - 15″ 2.5GHz... Read more
College Student Deals: Additional $100 off Ma...
Take an additional $100 off all MacBooks and iMacs at Best Buy Online with their College Students Deals Savings, valid through July 11, 2015. Anyone with a valid .EDU email address can take advantage... Read more
Apple refurbished Time Capsules available for...
The Apple Store has certified refurbished Time Capsules available for $100 off MSRP. Apple’s one-year warranty is included with each Time Capsule, and shipping is free: - 2TB Time Capsule: $199, $100... Read more
Newsweek Launches iPhone App
The venerable weekly news magazine Newsweek, owned by IBT Media, has announced the launch of its first iPhone app. The new app is available through Apple’s App Store and will allow consumers to read... Read more
New Initiative Covering 80 Million Homes Will...
Today, Internet service providers, equipment suppliers and retail equipment manufacturers joined the Consumer Electronics Association (CEA) and the National Cable & Telecommunications Association... Read more

Jobs Board

Architect / Senior Software Engineer, *Apple...
**Job Summary** Apple Pay is already changing our pay-habit in a deeper and fundamental level. We are looking for a software engineer with a passion for large scale inte Read more
Project Manager, *Apple* Retail New Store O...
**Job Summary** An Apple Retail New Store Openings & Remodels Project Manager is responsible for successfully managing the openings, remodels, and small works of Read more
*Apple* Solutions Consultant - Retail Sales...
**Job Summary** As an Apple Solutions Consultant (ASC) you are the link between our customers and our products. Your role is to drive the Apple business in a retail Read more
Program Manger, WW *Apple* Direct Fulfillme...
**Job Summary** We are seeking a business analyst to work within our Worldwide Apple Direct Fulfillment Operations team. This role will work closely with related program Read more
Hardware Design Validation Engineer - *Apple...
**Job Summary** The Apple Watch team is looking for a Hardware Design Validation Engineer. This person will be part of the Apple Watch hardware team with Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.