TweetFollow Us on Twitter

Checking Out Kiosk Mode Features

Volume Number: 19 (2003)
Issue Number: 12
Column Tag: Programming

Mac OS X Programming Secrets

Checking Out Kiosk Mode Features

by Scott Knaster

For about 20 years now, Apple has been telling us that modes in software are bad. It's hard to remember, especially if you're a youngster, but we used to drive software around by getting into and out of modes, restricted places that provided their own definitions for the way commands worked and actions were interpreted (kind of the way a lot of venerable UNIX text editors and command line tools work in OS X today, except this was for everybody, not just us geeks). For example, when you typed a slash into a little old spreadsheet program called VisiCalc, you went into command mode, signaling that the next character was an instruction rather than something that should appear in a cell.

But Apple in its wisdom says modes are OK in certain situations. For example, modes that emulate the real world are permitted, such as picking a type of brush in a painting program. Another kind of mode is useful when you intentionally want to limit what your users can do. This rare situation becomes reality when you consider the kiosk, a public computer that has to fend for itself when accosted by clueless newbies, hostile geeks, and keyboard-pounding toddlers.

If you're developing an application that has to run at a kiosk, Apple helps you out by providing a set of features for kiosk mode in Mac OS X. In this column, we'll take a look at how to take advantage of what OS X can do for you in kiosk mode.

Simple API

Apple put the cool new kiosk mode features into OS X 10.2, adding a little more in 10.3. You get to the features through two function calls: SetSystemUIMode and GetSystemUIMode. These calls let you effectively lock the user inside your application, preventing the hostile, curious, or ignorant from wreaking havoc. The SetSystemUIMode call is defined like this:

OSStatus SetSystemUIMode (SystemUIMode inMode,
                                        SystemUIOptions inOptions);

The inMode parameter specifies the UI mode you want, and inOptions lets you choose settings for that mode. There are five modes you can pick for your application, as shown in the following table:

System UI mode setting      Details

kUIModeNormal               The usual mode for all applications, and the mode you get if you don't 
                            make any calls to this API.
                            
kUIModeContentSuppressed    This mode prevents the system from drawing anything into the content 
                            area of the screen below the menu bar unless the user performs an action 
                            that triggers an auto-show behavior. In practice, this mode simply turns 
                            dock hiding on, which makes the dock vanish until the mouse pointer 
                            moves over it, whereupon it slides onto the screen. Note: this was 
                            broken in 10.2 and is fixed in 10.3.  
                            
kUIModeContentHidden        This mode hides the dock - technically, all system UI elements other 
                            than the menu bar - and does not show it even if the user mouses into 
                            the dock region. Note: this was also broken in 10.2 and fixed in 10.3.
                            
kUIModeAllHidden            Use this mode to hide the menu bar along with the dock, with no 
                            auto-showing feature.   
                            
kUIModeAllSuppressed        This mode was added in 10.3. Use it for hiding the dock and menu bar, 
                            but in this mode they will both auto-show if the user mouses over their 
                            content areas.  

When you call SetSystemUIMode, you also get to pass a set of options in addition to the mode you want to use. These options provide even more lock-in features for your kiosk and help you further refine the imprisonment of your rowdy user. Here's a list of the options you can choose:

System UI option                    Details

kUIOptionDisableAppleMenu           Use this option to disable all items in the Apple menu, 
                                    although despite the option's name, the appearance of the 
                                    Apple itself isn't disabled (must be a corporate logo thing). 
                                    
kUIOptionDisableProcessSwitch       This option turns off the user's ability to switch apps using 
                                    Command-Tab and Command-Shift-Tab.  
                                    
kUIOptionDisableForceQuit           If you select this option, the Force Quit item in the Apple 
                                    menu is disabled, and Command-Option-Escape doesn't do 
                                    anything. Powerful!  
                                    
kUIOptionDisableSessionTerminate    This option helps prevent the user from shutting down or 
                                    logging out. When you use it, the Restart, Shut Down, and 
                                    Log Out menu items are disabled. Also, if the user presses 
                                    the power button, the Restart/Sleep/Cancel/Shut Down alert 
                                    won't appear.  
                                    
kUIOptionAutoShowMenuBar            This option is only valid when used with kUIModeAllHidden. 
                                    Pass it to make the menu bar show itself if the user rolls 
                                    the mouse into its content region.  
                                    
kUIOptionDisableHide                This option was added in 10.3. Set it to disable the Hide item 
                                    in the application menu.  


Figure 1. You can use SetSystemUIMode to prevent users from getting access to the Force Quit and Power windows.

One of the cautions to note in using SetSystemUIMode is that the mode you set is only respected when your application is frontmost. If through magical incantation or other method the user somehow manages to bring another application to the front, the UI mode for your application is switched out along with the rest of the app.

There is a corresponding call to find out the current UI mode:

GetSystemUIMode(SystemUIMode *outMode, 
                        SystemUIOptions *outOptions);

As you can guess, calling GetSystemUIMode gets the current mode and options, in case you need to know what they are.

Depending on what your kiosk does, you might want to make the Finder go away. One good reason for this is that it prevents users from clicking on the desktop to switch out of your application. You can get rid of the Finder by sending it a kAEQuitApplication Apple event. Apple has an example to show you how to do that - it's at http://developer.apple.com/technotes/tn2002/downloads/tn2062_2.hqx .

If you just want your application to start up in one of the modified system UI modes and stay there, and you don't need to set any options, you can specify your desire in the application's property list. Just add a key named LSUIPresentationMode with type number and a value of 0, 1, 2, 3, or 4. Use 0 for normal mode, 1 for content suppressed, 2 for content hidden, 3 for all hidden, and 4 for all suppressed.

To help you view the power of the kiosk mode APIs in all their majesty, Apple provides a cool sample app, called UsingSystemUIMode, that demonstrates the various available features and tweaks. See Figure 2 for a shot of the app's screen.


Figure 2. Apple's sample application for testing kiosk mode APIs.

To get the sample app and to learn more about implementing kiosk mode in your application, see Technical Note TN2062, Guide to Creating Kiosks on Mac OS X, available at http://developer.apple.com/technotes/tn2002/tn2062.html.

No Can Do

Although the kiosk mode API is a good start toward locking up your kiosk machine, there are some things you'll want to do that you can't do yet. And just when you thought everything was perfect. Here's more information about some of those limitations:

You can't disable the eject key. If your kiosk has to run with a CD or DVD inserted, you can design the kiosk so that it's physically impossible to eject the disk.

To disable various wacky scenarios, such as taking control of the machine by booting off an external disk or booting into single-user mode by holding down Command-S, you can enable the Mac's Open Firmware password. When the Open Firmware password is enabled, the Mac will only boot from the startup disk you select in System Preferences.

You can't prevent the user from messing with the brightness keys and darkening the screen, nor can you intercept the volume keys.

One More Thing

Needless to say, locking your users in and preventing them from having basic features is not a standard design principle. In a kiosk, many of these features are necessary. In a typical app, they're practically criminal. Please use them with care, or at least a sense of humor.


Scott Knaster has been writing about Macs for as long as there have been Macs. Scott's books How To Write Macintosh Software and Macintosh Programming Secrets were required reading for Mac programmers for more than a decade. Scott wrote developer books for General Magic and worked on Mac software for Microsoft. Scott's books have been translated into Japanese and Pascal. Scott has every issue of Mad magazine, which explains a lot.

 

Community Search:
MacTech Search:

Software Updates via MacUpdate

Logic Pro X 10.1.1 - Music creation and...
Apple Logic Pro X is the most advanced version of Logic ever. Sophisticated new tools for professional songwriting, editing, and mixing are built around a modern interface that's designed to get... Read more
VLC Media Player 2.2.0 - Popular multime...
VLC Media Player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, MP3, OGG, ...) as well as DVDs, VCDs, and various streaming protocols. It... Read more
Sound Studio 4.7.8 - Robust audio record...
Sound Studio lets you easily record and professionally edit audio on your Mac. Easily rip vinyls and digitize cassette tapes, or record lectures and voice memos. Prepare for live shows with live... Read more
LibreOffice 4.4.1.2 - Free, open-source...
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 7.0.3 - Drag-and-drop Web de...
Freeway Pro lets you build websites with speed and precision... without writing a line of code! With its user-oriented drag-and-drop interface, Freeway Pro helps you piece together the website of... Read more
Cloud 3.3.0 - File sharing from your men...
Cloud is simple file sharing for the Mac. Drag a file from your Mac to the CloudApp icon in the menubar and we take care of the rest. A link to the file will automatically be copied to your clipboard... Read more
Cyberduck 4.6.5 - FTP and SFTP browser....
Cyberduck is a robust FTP/FTP-TLS/SFTP browser for the Mac whose lack of visual clutter and cleverly intuitive features make it easy to use. Support for external editors and system technologies such... Read more
Firefox 36.0 - Fast, safe Web browser. (...
Firefox for Mac offers a fast, safe Web browsing experience. Browse quickly, securely, and effortlessly. With its industry-leading features, Firefox is the choice of Web development professionals and... Read more
Thunderbird 31.5.0 - Email client from M...
As of July 2012, Thunderbird has transitioned to a new governance model, with new features being developed by the broader free software and open source community, and security fixes and improvements... Read more
VOX 2.4 - Music player that supports man...
VoxIt just sounds better! The beauty is in its simplicity, yet behind the minimal exterior lies a powerful music player with a ton of features & support for all audio formats you should ever need... Read more

Get The Whole Story – Lone Wolf Complete...
Get The Whole Story – Lone Wolf Complete is Now Available and On Sale Posted by Jessica Fisher on February 27th, 2015 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
Check Out the Trailer for the Upcoming F...
Check Out the Trailer for the Upcoming FINAL FANTASY: Record Keeper Posted by Jessica Fisher on February 26th, 2015 [ permalink ] DeNA and Square Enix have announced that | Read more »
Legacy Quest is an Upcoming Rouge-like T...
Legacy Quest is an Upcoming Rouge-like That’ll Kill the Whole Family Posted by Jessica Fisher on February 26th, 2015 [ permalink ] Nexon Co. | Read more »
Grudgeball: Enter the Chaosphere Review
Grudgeball: Enter the Chaosphere Review By Jordan Minor on February 26th, 2015 Our Rating: :: MUSCLE MENUniversal App - Designed for iPhone and iPad Regular Show gets an above average game.   | Read more »
Action RPG League of Angels – Fire Raide...
Gaia is being invaded by the Devil Prince and the demonic Devil Army at his disposal, and it’s up to you and your avatar to defeat him in League of Angels – Fire Raiders. Raise a mighty army from hundreds of recruitable angel heroes and take the... | Read more »
Burn Rubber on the Ice With a New Cars:...
Burn Rubber on the Ice With a New Cars: Fast as Lightning Update Posted by Jessica Fisher on February 26th, 2015 [ permalink ] Universal App - Designed for iPhone and iPad | Read more »
AdVenture Capitalist Review
AdVenture Capitalist Review By Jordan Minor on February 26th, 2015 Our Rating: :: DAS KAPITALUniversal App - Designed for iPhone and iPad An inadvertent Marxist manifesto.   | Read more »
Monster vs Sheep Review
Monster vs Sheep Review By Jennifer Allen on February 25th, 2015 Our Rating: :: SAMEY FUNUniversal App - Designed for iPhone and iPad What Monster vs Sheep lacks in variety it makes up for with stress relieving fun. At least, for a... | Read more »
Is Your Face Ready for the New Outwitter...
Is Your Face Ready for the New Outwitters 2.0 Trailer? Posted by Jessica Fisher on February 25th, 2015 [ permalink ] One Man Left Studios has announced that their turn-based strategy game, | Read more »
HowToFormat Review
HowToFormat Review By Jennifer Allen on February 25th, 2015 Our Rating: :: USEFUL TIPSiPhone App - Designed for the iPhone, compatible with the iPad Making a presentation and want to get it just right? HowToFormat teaches you how... | Read more »

Price Scanner via MacPrices.net

Apple restocks refurbished Mac minis for up t...
The Apple Store has restocked Apple Certified Refurbished 2014 Mac minis, with models available starting at $419. Apple’s one-year warranty is included with each mini, and shipping is free: - 1.4GHz... Read more
Save up to $50 on iPad Air 2s, NY tax only, f...
 B&H Photo has iPad Air 2s on sale for $50 off MSRP including free shipping plus NY sales tax only: - 16GB iPad Air 2 WiFi: $469.99 $30 off - 64GB iPad Air 2 WiFi: $549 $50 off - 128GB iPad Air 2... Read more
16GB iPad Air 2 on sale for $447, save $52
Walmart has the 16GB iPad Air 2 WiFi on sale for $446.99 on their online store for a limited time. Choose free shipping or free local store pickup (if available). Sale price for online orders only,... Read more
iMacs on sale for up to $205 off MSRP
B&H Photo has 21″ and 27″ iMacs on sale for up to $205 off MSRP including free shipping plus NY sales tax only: - 21″ 1.4GHz iMac: $1029 $70 off - 21″ 2.7GHz iMac: $1199 $100 off - 21″ 2.9GHz... Read more
Apple Takes 89 Percent Share of Global Smartp...
According to the latest research from Strategy Analytics, global smartphone operating profit reached US$21 billion in Q4 2014. The Android operating system captured a record-low 11 percent global... Read more
New Travel Health App “My Travel Health” iOS...
Rochester, Minnesota based Travel Health and Wellness LLC has announced that its new iOS app help safeguard the user’s health when traveling abroad — “My Travel Health” is now available on the Apple... Read more
Sale! MacBook Airs for up to $115 off MSRP
B&H Photo has MacBook Airs on sale for up to $100 off MSRP. Shipping is free, and B&H charges NY sales tax only: - 11″ 128GB MacBook Air: $799 100 off MSRP - 11″ 256GB MacBook Air: $999 $100... Read more
15-inch 2.0GHz Retina MacBook Pro (refurbishe...
The Apple Store has Apple Certified Refurbished previous-generation 15″ 2.0GHz Retina MacBook Pros available for $1489 including free shipping plus Apple’s standard one-year warranty. Their price is... Read more
Wither The iPad mini? End Of The Road Imminen...
AppleDailyReport’s Dennis Sellers predicts that the iPad mini is going to be left to wither on the vine, as it were, and then just allowed to fade away — a casualty of the IPhone 6 Plus and other... Read more
Android and iOS Duopoly Owns 96.3% of Smartph...
IDC reports that Android and iOS inched closer to total domination of the worldwide smartphone market in both the fourth quarter (4Q14) and the calendar year 2014 (CY14). According to data from the... Read more

Jobs Board

Sr. Technical Services Consultant, *Apple*...
**Job Summary** Apple Professional Services (APS) has an opening for a senior technical position that contributes to Apple 's efforts for strategic and transactional Read more
Event Director, *Apple* Retail Marketing -...
…This senior level position is responsible for leading and imagining the Apple Retail Team's global engagement strategy and team. Delivering an overarching brand Read more
*Apple* Pay - Site Reliability Engineer - 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
*Apple* Solutions Consultant - Retail Sales...
**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
*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
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.