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

1Password 6.6.1 - Powerful password mana...
1Password is a password manager that uniquely brings you both security and convenience. It is the only program that provides anti-phishing protection and goes beyond password management by adding Web... Read more
Safari Technology Preview 10.2 - The new...
Safari Technology Preview contains the most recent additions and improvements to WebKit and the latest advances in Safari web technologies. And once installed, you will receive notifications of... Read more
Eye Candy 7.2.0.50 - 30 professional Pho...
Eye Candy renders realistic effects that are difficult or impossible to achieve in Photoshop alone, such as Fire, Chrome, and the new Lightning. Effects like Animal Fur, Smoke, and Reptile Skin are... Read more
Microsoft Office 2016 15.31 - Popular pr...
Microsoft Office 2016 - Unmistakably Office, designed for Mac. The new versions of Word, Excel, PowerPoint, Outlook and OneNote provide the best of both worlds for Mac users - the familiar Office... Read more
Spotify 1.0.49.125. - Stream music, crea...
Spotify is a streaming music service that gives you on-demand access to millions of songs. Whether you like driving rock, silky R&B, or grandiose classical music, Spotify's massive catalogue puts... Read more
QuickBooks 16.1.12.1564 R13 - Financial...
QuickBooks helps you manage your business easily and efficiently. Organize your finances all in one place, track money going in and out of your business, and spot areas where you can save. Built for... Read more
Dash 4.0.1 - 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
Tinderbox 7.0.0 - Store and organize you...
Tinderbox is a personal content management assistant. It stores your notes, ideas, and plans. It can help you organize and understand them. And Tinderbox helps you share ideas through Web journals... Read more
Apple Remote Desktop Client 3.9 - Client...
Apple Remote Desktop Client is the best way to manage the Mac computers on your network. Distribute software, provide real-time online help to end users, create detailed software and hardware reports... Read more
Sparkle 2.1.1 - $79.99
Sparkle will change your mind if you thought building websites wasn't for you. Sparkle is the intuitive site builder that lets you create sites for your online portfolio, team or band pages, or... Read more

Tavern Guardians (Games)
Tavern Guardians 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: Tavern Guardians is a Hack-and-Slash action game played in the style of a match-three. You can experience high pace action... | Read more »
Slay your way to glory in idle RPG Endle...
It’s a golden age for idle games on the mobile market, and those addictive little clickers have a new best friend. South Korean developer Ekkorr released Endless Frontier last year, and players have been idling away the hours in the company of its... | Read more »
Tiny Striker: World Football Guide - How...
| Read more »
Good news everyone! Futurama: Worlds of...
Futurama is finding a new home on mobile in TinyCo and Fox Interactive's new game, Futurama: Worlds of Tomorrow. They're really doing it up, bringing on board Futurama creator Matt Groening along with the original cast and writers. TinyCo wants... | Read more »
MUL.MASH.TAB.BA.GAL.GAL (Games)
MUL.MASH.TAB.BA.GAL.GAL 1.0 Device: iOS Universal Category: Games Price: $2.99, Version: 1.0 (iTunes) Description: ENDLESS UPGRADES. CONSTANT DANGER. ANCIENT WISDOM. BOUNCY BALLS. Launch Sale, 40% OFF for a very limited time!!! MUL.... | Read more »
Dungeon Rushers (Games)
Dungeon Rushers 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: Dungeon Rushers is a 2D tactical RPG combining dungeon crawler’s gameplay and turn based fights. Manage your team, loot dusty... | Read more »
Blasty Bubs is a colorful Pinball and Br...
QuickByte Games has another arcade treat in the works -- this time it's a mishmash of brick breaking and Pinball mechanics. It's called Blasty Bubs, and it's a top down brickbreaker that has you slinging balls around a board. [Read more] | Read more »
Corsola and Heracross are the new region...
Generation 2 finally launched in Pokémon GO, unleashing a brand new batch of Pokémon into the wild. Even before the update went live people were speculating on how to catch elusive Pokémon like the legendary "dogs", Unknown, and whether or not... | Read more »
The Warlock of Firetop Mountain (Games)
The Warlock of Firetop Mountain 1.0 Device: iOS Universal Category: Games Price: $4.99, Version: 1.0 (iTunes) Description: An epic adventure through a mysterious mountain filled with monsters, magic and mayhem! “...it looks downright... | Read more »
Fantasy MMORPG MU Origin’s receives a hu...
Developer Webzen are looking to take their highly popular fantasy battler MU Origin to the next level this month, with its most ambitious overhaul yet. The latest update introduces the long sought after Server Arena, new treasure dungeons, and much... | Read more »

Price Scanner via MacPrices.net

Apple restocks refurbished 11-inch MacBook Ai...
Apple has Certified Refurbished 11″ MacBook Airs (the latest models recently discontinued by Apple), available for up to $170 off original MSRP. An Apple one-year warranty is included with each... Read more
Apple Park Opens to Employees in April With T...
Apple has announced that Apple Park, the company’s new 175-acre campus, will be ready for employees to begin occupying in April. The process of moving more than 12,000 people will take over six... Read more
Manhattan Neighbors for Safer Telecommunicati...
A new education and advocacy group focused on cell phone and wireless risks, Manhattan Neighbors for Safer Telecommunications, launched today at http://www.ManhattanNeighbors.org. Manhattan... Read more
Portable Dual DisplayPort Monitor Dock Enable...
IOGEAR has announced the launch of its USB-C Dual DisplayPort Monitor Portable Dock (GUC3CMST). The dock enables users to easily connect two DisplayPort monitors to a USB-C or Thunderbolt 3 laptop to... Read more
13-inch 2.7GHz Retina MacBook Pro on sale for...
Amazon.com has restocked the 13″ 2.7GHz/128GB Retina MacBook Pro (MF839LL/A) for $200 off MSRP including free shipping: - 13″ 2.7GHz/128GB Retina MacBook Pro: $1099 $200 off MSRP This model tends to... Read more
Apple’s New iPad Ads Don’t Address Pro Users’...
Apple launched a new tranche of iPad Pro TV ads last week addressing actual queries and challenges from the Twitterverse, albeit using actors for the visuals. That’s great. As an iPad fan and heavy... Read more
Free Verbum Catholic Bible Study App For iOS
The Verbum mobile app runs on Logos’ powerful Bible software and is an advanced resource for mobile Catholic study. The Verbum app surrounds the Bible with the Tradition. Verbum comes with 15 free... Read more
27-inch Apple iMacs on sale for up to $200 of...
B&H Photo has 27″ Apple iMacs on sale for up to $200 off MSRP, each including free shipping plus NY sales tax only: - 27″ 3.3GHz iMac 5K: $2099.99 $200 off MSRP - 27″ 3.2GHz/1TB Fusion iMac 5K: $... Read more
15-inch 2.2GHz Retina MacBook Pro on sale for...
Amazon has 2015 15″ 2.2GHz Retina MacBook Pros (MJLQ2LL/A) available for $1849.99 including free shipping. Apple charges $1999 for this model, so Amazon’s price is represents a $150 savings. Read more
Apple refurbished iPad Air 2s available start...
Apple has Certified Refurbished iPad Air 2 WiFis available for starting at $319 including free shipping. A standard Apple one-year warranty is included: - 16GB iPad Air 2 WiFi: $319 $60 off original... Read more

Jobs Board

Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and 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
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and 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
Manager *Apple* Systems Administration - Pu...
Req ID 3315BR Position Title Manager, Apple Systems Administration Job Description The Manager of Apple Systems Administration oversees the administration and Read more
All contents are Copyright 1984-2011 by Xplain Corporation. All rights reserved. Theme designed by Icreon.