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NSUserDefaults Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/Foundation.framework
Availability
Available in Mac OS X v10.0 and later.
Companion guide
Declared in
NSUserDefaults.h
Related sample code

Overview

The NSUserDefaults class provides a programmatic interface for interacting with the defaults system. The defaults system allows an application to customize its behavior to match a user’s preferences. For example, you can allow users to determine what units of measurement your application displays or how often documents are automatically saved. Applications record such preferences by assigning values to a set of parameters in a user’s defaults database. The parameters are referred to as defaults since they’re commonly used to determine an application’s default state at startup or the way it acts by default.

At runtime, you use an NSUserDefaults object to read the defaults that your application uses from a user’s defaults database. NSUserDefaults caches the information to avoid having to open the user’s defaults database each time you need a default value. The synchronize method, which is automatically invoked at periodic intervals, keeps the in-memory cache in sync with a user’s defaults database.

A default’s value must be a property list, that is, an instance of (or for collections a combination of instances of): NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary. If you want to store any other type of object, you should typically archive it to create an instance of NSData. For more details, see User Defaults Programming Topics for Cocoa.

Values returned from NSUserDefaults are immutable, even if you set a mutable object as the value. For example, if you set a mutable string as the value for "MyStringDefault", the string you later retrieve using stringForKey: will be immutable.

A defaults database is created automatically for each user. The NSUserDefaults class does not currently support per-host preferences. To do this, you must use the CFPreferences API (see Preferences Utilities Reference). However, NSUserDefaults correctly reads per-host preferences, so you can safely mix CFPreferences code with NSUserDefaults code.

If your application supports managed environments, you can use an NSUserDefaults object to determine which preferences are managed by an administrator for the benefit of the user. Managed environments correspond to computer labs or classrooms where an administrator or teacher may want to configure the systems in a particular way. In these situations, the teacher can establish a set of default preferences and force those preferences on users. If a preference is managed in this manner, applications should prevent users from editing that preference by disabling any appropriate controls.

The NSUserDefaults class is thread-safe.

Tasks

Getting the Shared NSUserDefaults Instance

Initializing an NSUserDefaults Object

Getting a Default Value

Setting and Removing Defaults

Registering Defaults

Maintaining Persistent Domains

Accessing Managed Environment Keys

Managing the Search List

Maintaining Volatile Domains

Maintaining Suites

Class Methods

resetStandardUserDefaults

Synchronizes any changes made to the shared user defaults object and releases it from memory.

+ (void)resetStandardUserDefaults

Discussion

A subsequent invocation of standardUserDefaults creates a new shared user defaults object with the standard search list.

Availability
Declared In
NSUserDefaults.h

standardUserDefaults

Returns the shared defaults object.

+ (NSUserDefaults *)standardUserDefaults

Return Value

The shared defaults object.

Discussion

If the shared defaults object does not exist yet, it is created with a search list containing the names of the following domains, in this order:

The defaults are initialized for the current user. Subsequent modifications to the standard search list remain in effect even when this method is invoked again—the search list is guaranteed to be standard only the first time this method is invoked. The shared instance is provided as a convenience—you can create custom instances using alloc along with initWithUser: or init.

Availability
Related Sample Code
Declared In
NSUserDefaults.h

Instance Methods

addSuiteNamed:

Inserts the specified domain name into the receiver’s search list.

- (void)addSuiteNamed:(NSString *)suiteName

Parameters
suiteName

The domain name to insert. This domain is inserted after the application domain.

Discussion

The suiteName domain is similar to a bundle identifier string, but is not tied to a particular application or bundle. A suite can be used to hold preferences that are shared between multiple applications.

Availability
See Also
Declared In
NSUserDefaults.h

arrayForKey:

Returns the array associated with the specified key.

- (NSArray *)arrayForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The array associated with the specified key, or nil if the key does not exist or its value is not an NSArray object.

Special Considerations

The returned array and its contents are immutable, even if the values you originally set were mutable.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

boolForKey:

Returns the Boolean value associated with the specified key.

- (BOOL)boolForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

If a boolean value is associated with defaultName in the user defaults, that value is returned. Otherwise, NO is returned.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

dataForKey:

Returns the data object associated with the specified key.

- (NSData *)dataForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The data object associated with the specified key, or nil if the key does not exist or its value is not an NSData object.

Special Considerations

The returned data object is immutable, even if the value you originally set was a mutable data object.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

dictionaryForKey:

Returns the dictionary object associated with the specified key.

- (NSDictionary *)dictionaryForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The dictionary object associated with the specified key, or nil if the key does not exist or its value is not an NSDictionary object.

Special Considerations

The returned dictionary and its contents are immutable, even if the values you originally set were mutable.

Availability
See Also
Declared In
NSUserDefaults.h

dictionaryRepresentation

Returns a dictionary that contains a union of all key-value pairs in the domains in the search list.

- (NSDictionary *)dictionaryRepresentation

Return Value

A dictionary containing the keys. The keys are names of defaults and the value corresponding to each key is a property list object (NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary).

Discussion

As with objectForKey:, key-value pairs in domains that are earlier in the search list take precedence. The combined result does not preserve information about which domain each entry came from.

Availability
Related Sample Code
Declared In
NSUserDefaults.h

floatForKey:

Returns the floating-point value associated with the specified key.

- (float)floatForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The floating-point value associated with the specified key. If the key does not exist, this method returns 0.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

init

Returns an NSUserDefaults object initialized with the defaults for the current user account.

- (id)init

Return Value

An initialized NSUserDefaults object whose argument and registration domains are already set up.

Discussion

This method does not put anything in the search list. Invoke it only if you’ve allocated your own NSUserDefaults instance instead of using the shared one.

Availability
See Also
Declared In
NSUserDefaults.h

initWithUser:

Returns an NSUserDefaults object initialized with the defaults for the specified user account.

- (id)initWithUser:(NSString *)username

Parameters
username

The name of the user account.

Return Value

An initialized NSUserDefaults object whose argument and registration domains are already set up. If the current user does not have access to the specified user account, this method returns nil.

Discussion

This method does not put anything in the search list. Invoke it only if you’ve allocated your own NSUserDefaults instance instead of using the shared one.

You do not normally use this method to initialize an instance of NSUserDefaults. Applications used by a superuser might use this method to update the defaults databases for a number of users. The user who started the application must have appropriate access (read, write, or both) to the defaults database of the new user, or this method returns nil.

Availability
See Also
Declared In
NSUserDefaults.h

integerForKey:

Returns the integer value associated with the specified key..

- (NSInteger)integerForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The integer value associated with the specified key. If the specified key does not exist, this method returns 0.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

objectForKey:

Returns the object associated with the first occurrence of the specified default.

- (id)objectForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The object associated with the specified key, or nil if the key was not found.

Discussion

This method searches the domains included in the search list in the order they are listed.

Special Considerations

The returned object is immutable, even if the value you originally set was mutable.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

objectIsForcedForKey:

Returns a Boolean value indicating whether the specified key is managed by an administrator.

- (BOOL)objectIsForcedForKey:(NSString *)key

Parameters
key

The key whose status you want to check.

Return Value

YES if the value of the specified key is managed by an administrator, otherwise NO.

Discussion

This method assumes that the key is a preference associated with the current user and application. For managed keys, the application should disable any user interface that allows the user to modify the value of key.

Availability
See Also
Declared In
NSUserDefaults.h

objectIsForcedForKey:inDomain:

Returns a Boolean value indicating whether the key in the specified domain is managed by an administrator.

- (BOOL)objectIsForcedForKey:(NSString *)key inDomain:(NSString *)domain

Parameters
key

The key whose status you want to check.

domain

The domain of the key.

Return Value

YES if the key is managed by an administrator in the specified domain, otherwise NO.

Discussion

This method assumes that the key is a preference associated with the current user. For managed keys, the application should disable any user interface that allows the user to modify the value of key.

Availability
See Also
Declared In
NSUserDefaults.h

persistentDomainForName:

Returns a dictionary containing the keys and values in the specified persistent domain.

- (NSDictionary *)persistentDomainForName:(NSString *)domainName

Parameters
domainName

The domain whose keys and values you want. This value should be equal to your application's bundle identifier.

Return Value

A dictionary containing the keys. The keys are names of defaults and the value corresponding to each key is a property list object (NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary).

Availability
See Also
Declared In
NSUserDefaults.h

persistentDomainNames

Returns an array of the current persistent domain names.

- (NSArray *)persistentDomainNames

Return Value

An array of NSString objects containing the domain names.

Discussion

You can get the keys and values for each domain by passing the returned domain names to the persistentDomainForName: method.

Availability
See Also
Declared In
NSUserDefaults.h

registerDefaults:

Adds the contents the specified dictionary to the registration domain.

- (void)registerDefaults:(NSDictionary *)dictionary

Parameters
dictionary

The dictionary of keys and values you want to register.

Discussion

If there is no registration domain, one is created using the specified dictionary, and NSRegistrationDomain is added to the end of the search list.

The contents of the registration domain are not written to disk; you need to call this method each time your application starts. You can place a plist file in the application's Resources directory and call registerDefaults: with the contents that you read in from that file.

Availability
Related Sample Code
Declared In
NSUserDefaults.h

removeObjectForKey:

Removes the value of the specified default key in the standard application domain.

- (void)removeObjectForKey:(NSString *)defaultName

Parameters
defaultName

The key whose value you want to remove.

Discussion

Removing a default has no effect on the value returned by the objectForKey: method if the same key exists in a domain that precedes the standard application domain in the search list.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

removePersistentDomainForName:

Removes the contents of the specified persistent domain from the user’s defaults.

- (void)removePersistentDomainForName:(NSString *)domainName

Parameters
domainName

The domain whose keys and values you want. This value should be equal to your application's bundle identifier.

Discussion

When a persistent domain is changed, an NSUserDefaultsDidChangeNotification is posted.

Availability
See Also
Declared In
NSUserDefaults.h

removeSuiteNamed:

Removes the specified domain name from the receiver’s search list.

- (void)removeSuiteNamed:(NSString *)suiteName

Parameters
suiteName

The domain name to remove.

Availability
See Also
Declared In
NSUserDefaults.h

removeVolatileDomainForName:

Removes the specified volatile domain from the user’s defaults.

- (void)removeVolatileDomainForName:(NSString *)domainName

Parameters
domainName

The volatile domain you want to remove.

Availability
See Also
Declared In
NSUserDefaults.h

setBool:forKey:

Sets the value of the specified default key to a string containing a Boolean value.

- (void)setBool:(BOOL)value forKey:(NSString *)defaultName

Parameters
value

The Boolean value to store in the defaults database.

defaultName

The key with which to associate with the value.

Discussion

Invokes setObject:forKey: as part of its implementation.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

setFloat:forKey:

Sets the value of the specified default key to a string containing a floating-point value.

- (void)setFloat:(float)value forKey:(NSString *)defaultName

Parameters
value

The floating-point value to store in the defaults database.

defaultName

The key with which to associate with the value.

Discussion

Invokes setObject:forKey: as part of its implementation.

Availability
See Also
Declared In
NSUserDefaults.h

setInteger:forKey:

Sets the value of the specified default key to a string containing an integer value.

- (void)setInteger:(NSInteger)value forKey:(NSString *)defaultName

Parameters
value

The integer value to store in the defaults database.

defaultName

The key with which to associate with the value.

Discussion

Invokes setObject:forKey: as part of its implementation.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

setObject:forKey:

Sets the value of the specified default key in the standard application domain.

- (void)setObject:(id)value forKey:(NSString *)defaultName

Parameters
value

The object to store in the defaults database. A default’s value can be only property list objects: NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary.

defaultName

The key with which to associate with the value.

Discussion

Setting a default has no effect on the value returned by the objectForKey: method if the same key exists in a domain that precedes the application domain in the search list.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

setPersistentDomain:forName:

Sets the dictionary for the specified persistent domain.

- (void)setPersistentDomain:(NSDictionary *)domain forName:(NSString *)domainName

Parameters
domain

The dictionary of keys and values you want to assign to the domain.

domainName

The domain whose keys and values you want to set. This value should be equal to your application's bundle identifier.

Discussion

When a persistent domain is changed, an NSUserDefaultsDidChangeNotification is posted.

Availability
See Also
Declared In
NSUserDefaults.h

setVolatileDomain:forName:

Sets the dictionary for the specified volatile domain.

- (void)setVolatileDomain:(NSDictionary *)domain forName:(NSString *)domainName

Parameters
domain

The dictionary of keys and values you want to assign to the domain.

domainName

The domain whose keys and values you want to set.

Discussion

This method raises an NSInvalidArgumentException if a volatile domain with the specified name already exists.

Availability
See Also
Declared In
NSUserDefaults.h

stringArrayForKey:

Returns the array of strings associated with the specified key.

- (NSArray *)stringArrayForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The array of NSString objects, or nil if the specified default does not exist, the default does not contain an array, or the array does not contain NSString objects.

Special Considerations

The returned array and its contents are immutable, even if the values you originally set were mutable.

Availability
See Also
Declared In
NSUserDefaults.h

stringForKey:

Returns the string associated with the specified key.

- (NSString *)stringForKey:(NSString *)defaultName

Parameters
defaultName

A key in the current user's defaults database.

Return Value

The string associated with the specified key, or nil if the default does not exist or does not contain a string.

Special Considerations

The returned string is immutable, even if the value you originally set was a mutable string.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

synchronize

Writes any modifications to the persistent domains to disk and updates all unmodified persistent domains to what is on disk.

- (BOOL)synchronize

Return Value

YES if the data was saved successfully to disk, otherwise NO.

Discussion

Because this method is automatically invoked at periodic intervals, use this method only if you cannot wait for the automatic synchronization (for example, if your application is about to exit) or if you want to update the user defaults to what is on disk even though you have not made any changes.

Availability
See Also
Related Sample Code
Declared In
NSUserDefaults.h

volatileDomainForName:

Returns the dictionary for the specified volatile domain.

- (NSDictionary *)volatileDomainForName:(NSString *)domainName

Parameters
domainName

The domain whose keys and values you want.

Return Value

The dictionary of keys and values belonging to the domain. The keys in the dictionary are names of defaults, and the value corresponding to each key is a property list object (NSData, NSString, NSNumber, NSDate, NSArray, or NSDictionary).

Availability
See Also
Declared In
NSUserDefaults.h

volatileDomainNames

Returns an array of the current volatile domain names.

- (NSArray *)volatileDomainNames

Return Value

An array of NSString objects with the volatile domain names.

Discussion

You can get the contents of each domain by passing the returned domain names to the volatileDomainForName: method.

Availability
See Also
Declared In
NSUserDefaults.h

Constants

NSUserDefaults Domains

These constants specify various user defaults domains.

extern NSString *NSGlobalDomain;
extern NSString *NSArgumentDomain;
extern NSString *NSRegistrationDomain;

Constants
NSGlobalDomain

The domain consisting of defaults meant to be seen by all applications.

Available in Mac OS X v10.0 and later.

Declared in NSUserDefaults.h.

NSArgumentDomain

The domain consisting of defaults parsed from the application’s arguments. These are one or more pairs of the form -default value included in the command-line invocation of the application.

Available in Mac OS X v10.0 and later.

Declared in NSUserDefaults.h.

NSRegistrationDomain

The domain consisting of a set of temporary defaults whose values can be set by the application to ensure that searches will always be successful.

Available in Mac OS X v10.0 and later.

Declared in NSUserDefaults.h.

Declared In
NSUserDefaults.h

Language-Dependent Date/Time Information

The NSUserDefaults class provides the following constants as a convenience. They provide access to values of the keys to the locale dictionary, which is discussed in User Defaults Programming Topics for Cocoa. (Deprecated. These constants are deprecated in Mac OS X v10.5. Where there are direct replacements, you can find typically them in NSDateFormatter—for example, monthSymbols, shortWeekdaySymbols, and AMSymbol—otherwise you should use the patterns described in Data Formatting Programming Guide for Cocoa.)

extern NSString *NSAMPMDesignation;
extern NSString *NSDateFormatString;
extern NSString *NSDateTimeOrdering;
extern NSString *NSEarlierTimeDesignations;
extern NSString *NSHourNameDesignations;
extern NSString *NSLaterTimeDesignations;
extern NSString *NSMonthNameArray;
extern NSString *NSNextDayDesignations;
extern NSString *NSNextNextDayDesignations;
extern NSString *NSPriorDayDesignations;
extern NSString *NSShortDateFormatString;
extern NSString *NSShortMonthNameArray;
extern NSString *NSShortTimeDateFormatString;
extern NSString *NSShortWeekDayNameArray;
extern NSString *NSThisDayDesignations;
extern NSString *NSTimeDateFormatString;
extern NSString *NSTimeFormatString;
extern NSString *NSWeekDayNameArray;
extern NSString *NSYearMonthWeekDesignations;

Constants
NSAMPMDesignation

Key for the value that specifies how the morning and afternoon designations are printed, affecting strings that use the %p format specifier. (Deprecated. Use AMSymbol or PMSymbol (NSDateFormatter) instead.)

The defaults are “AM” and “PM”.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSDateFormatString

Key for the format string that specifies how how dates are printed using the date format specifiers. (Deprecated. Use the appropriate API from NSDateFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is to use weekday names with full month names and full years, as in “Saturday, March 24, 2001.”

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSDateTimeOrdering

Key for the string that specifies how to use ambiguous numbers in date strings.

Specify this value as a permutation of the letters M (month), D (day), Y (year), and H (hour). For example, MDYH treats “2/3/01 10” as the 3rd day of February 2001 at 10:00 am, whereas DMYH treats the same value as the 2nd day of March 2001 at 10:00 am. If fewer numbers are specified than are needed, the numbers are prioritized to satisfy day first, then month, and then year. For example, if you supply only the value 12, it means the 12th day of this month in this year because the day must be specified. If you supply “2 12” it means either February 12 or December 2, depending on if the ordering is “MDYH” or “DMYH.”

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSEarlierTimeDesignations

Key for an array of strings that denote a time in the past. (Deprecated. There is no direct replacement. If you need to localize words such as “prior,” you should use a strings file as you would for any other localizable text—see Strings Files.)

These are adjectives that modify values from NSYearMonthWeekDesignations. The defaults are “prior,” “last,” “past,” and “ago.”

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSHourNameDesignations

Key for strings that identify the time of day.

These strings should be bound to an hour. The default is this array of arrays: (0, midnight), (10, morning), (12, noon, lunch), (14, afternoon), (19, dinner).

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSLaterTimeDesignations

Key for an array of strings that denote a time in the future. (Deprecated. There is no direct replacement. If you need to localize words such as “next,” you should use a strings file as you would for any other localizable text—see Strings Files.)

Strings in this array are adjectives that modify a value from NSYearMonthWeekDesignations.

The default is an array that contains a single string, "next".

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSMonthNameArray

Key for the value that specifies the names for the months, affecting strings that use the %B format specifier. (Deprecated. Use monthSymbols or—if you are going to display these in the user interface by themselves—standaloneMonthSymbols (NSDateFormatter) instead.)

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSNextDayDesignations

Key for an array of strings that denote the day after today. (Deprecated. There is no direct replacement. If you need to localize words such as “tomorrow,” you should use a strings file as you would for any other localizable text—see Strings Files.)

The default is an array that contains a single string, "tomorrow".

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSNextNextDayDesignations

Key for an array of strings that denote the day after tomorrow. (Deprecated. There is no direct replacement. If you need to localize words such as “nextday,” you should use a strings file as you would for any other localizable text—see Strings Files.)

The default is an array that contains a single string, "nextday".

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSPriorDayDesignations

Key for an array of strings that denote the day before today. (Deprecated. There is no direct replacement. If you need to localize words such as “yesterday,” you should use a strings file as you would for any other localizable text—see Strings Files.)

The default is an array that contains a single string, "yesterday".

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSShortDateFormatString

Key for a format string that specifies how dates are abbreviated. (Deprecated. Use the appropriate API from NSDateFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is to separate the day month and year with slashes and to put the day first, as in 31/10/01.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSShortWeekDayNameArray

Key for an array of strings that specify the abbreviations for the days of the week, affecting strings that use the %a format specifier. (Deprecated. Use shortWeekdaySymbols or—if you are going to display these in the user interface by themselves—shortStandaloneWeekdaySymbols (NSDateFormatter) instead.)

Sunday should be the first day of the week.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSShortMonthNameArray

Key for an array of strings that specify the abbreviations for the months, affecting strings that use the %b format specifier. (Deprecated. Use shortMonthSymbolsor—if you are going to display these in the user interface by themselves—shortStandaloneMonthSymbols (NSDateFormatter) instead.)

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSShortTimeDateFormatString

Key for a format string that specifies how times and dates are abbreviated. (Deprecated. Use the appropriate API fromNSDateFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is to use dashes to separate the day, month, and year and to use a 12-hour clock, as in "31-Jan-01 1:30 PM."]

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSThisDayDesignations

Key for an array of strings that specify what this day is called. (Deprecated. There is no direct replacement. If you need to localize words such as “today,” you should use a strings file as you would for any other localizable text—see Strings Files.)

The default is an array containing two strings, "today" and "now".

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSTimeDateFormatString

Key for the value that specifies how dates with times are printed, affecting strings that use the format specifiers %c, %X, or %x. (Deprecated. Use the appropriate API from NSDateFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is to use full month names and days with a 24-hour clock, as in "Sunday, January 01, 2001 23:00:00 Pacific Standard Time."

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSTimeFormatString

Key for a format string that specifies how dates with times are printed. (Deprecated. Use the appropriate API from NSDateFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is to use a 12-hour clock.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSWeekDayNameArray

Key for an array of strings that specify the names for the days of the week, affecting strings that use the %A format specifier. (Deprecated. Use weekdaySymbols or—if you are going to display these in the user interface by themselves—standaloneWeekdaySymbols (NSDateFormatter) instead.)

Sunday should be the first day of the week.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSYearMonthWeekDesignations

Key for an array of strings that specify the words for year, month, and week in the current locale. (Deprecated. There is no direct replacement. If you need to localize words such as “year,” you should use a strings file as you would for any other localizable text—see Strings Files.)

The defaults are “year,” “month,” and “week.”

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

Declared In
NSUserDefaults.h

Language-Dependent Numeric Information

The NSUserDefaults class provides the following constants as a convenience. They provide access to values of the keys to the locale dictionary, which is discussed in User Defaults Programming Topics for Cocoa. (Deprecated. These constants are deprecated in Mac OS X v10.5. Where there are replacements, you can typically find them in NSNumberFormatter or NSLocale—for example, currencySymbol, currencyDecimalSeparator, and thousandSeparator—otherwise you should use the patterns described in Data Formatting Programming Guide for Cocoa.)

extern NSString *NSCurrencySymbol;
extern NSString *NSDecimalDigits;
extern NSString *NSDecimalSeparator;
extern NSString *NSInternationalCurrencyString;
extern NSString *NSNegativeCurrencyFormatString;
extern NSString *NSPositiveCurrencyFormatString;
extern NSString *NSThousandsSeparator;

Constants
NSCurrencySymbol

A string that specifies the symbol used to denote currency in this language. (Deprecated. Use currencySymbol (NSNumberFormatter) or retrieve the NSLocaleCurrencySymbol from the current locale instead.)

The default is “$”.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSDecimalDigits

Strings that identify the decimal digits in addition to or instead of the ASCII digits.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSDecimalSeparator

A string that specifies the decimal separator. (Deprecated. Use decimalSeparator or currencyDecimalSeparator (NSNumberFormatter) or retrieve the NSLocaleDecimalSeparator from the current locale instead.)

The decimal separator separates the ones place from the tenths place. The default is “.”.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSInternationalCurrencyString

A string containing a three-letter abbreviation for currency, following the ISO 4217 standard. (Deprecated. Retrieve the NSLocaleCurrencySymbol from the current locale instead.)

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSNegativeCurrencyFormatString

A format string that specifies how negative numbers are printed when representing a currency value. (Deprecated. Use the appropriate API from NSNumberFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is –$9,999.00.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSPositiveCurrencyFormatString

A format string that specifies how positive numbers are printed when representing a currency value. (Deprecated. Use the appropriate API from NSNumberFormatter instead—see Data Formatting Programming Guide for Cocoa.)

The default is $9,999.00.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

NSThousandsSeparator

A string that specifies the separator character for the thousands place of a decimal number. (Deprecated. Retrieve the NSLocaleGroupingSeparator from the current locale instead.)

The default is a comma.

Available in Mac OS X v10.0 and later.

Deprecated in Mac OS X v10.5.

Declared in NSUserDefaults.h.

Declared In
NSUserDefaults.h

Notifications

NSUserDefaultsDidChangeNotification

This notification is posted when a change is made to defaults in a persistent domain.

The notification object is the NSUserDefaults object. This notification does not contain a userInfo dictionary.

Availability
Declared In
NSUserDefaults.h

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© 2009 Apple Inc. All Rights Reserved. (Last updated: 2009-04-08)

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