Tuparev@EMBL-Heidelberg.de
)rfm@gnu.org
)Version: 1.118
Date: 2005/02/22 14:06:28
Copyright: (C) 1995-2001 Free Software Foundation, Inc.
- Declared in:
- Foundation/NSUserDefaults.h
Standards:
- MacOS-X
- OpenStep
- GNUstep
NSUserDefaults provides an interface to the defaults system, which allows an application access to global and/or application specific defualts set by the user. A particular instance of NSUserDefaults, standardUserDefaults, is provided as a convenience. Most of the information described below pertains to the standardUserDefaults. It is unlikely that you would want to instantiate your own userDefaults object, since it would not be set up in the same way as the standardUserDefaults.
Defaults are managed based on domains.
Certain domains, such as
NSGlobalDomain
, are persistant. These
domains have defaults that are stored externally.
Other domains are volitale. The defaults in these
domains remain in effect only during the existance
of the application and may in fact be different for
applications running at the same time. When
asking for a default value from
standardUserDefaults, NSUserDefaults
looks through the various domains in a particular
order.
NSArgumentDomain
... volatile
--GNU-Debug=...
are used to
enable debugging. Despite beginning with a hyphen,
these are not treated as default keys.
NSGlobalDomain
... persistent
NSRegistrationDomain
... volatile
The NSLanguages default value is used to set
up the constants for localization. GNUstep will also
look for the LANGUAGES
environment
variable if it is not set in the defaults system.
If it exists, it consists of an array of languages that
the user prefers. At least one of the languages should
have a corresponding localization file (typically
located in the Languages
directory of
the GNUstep resources).
As a special extension, on systems that support locales
(e.g. GNU/Linux and Solaris), GNUstep will use
information from the user specified locale, if
the NSLanguages default value is not found.
Typically the locale is specified in the
environment with the LANG
environment variable.
The first change to a persistent domain after a -synchronize will cause an NSUserDefaultsDidChangeNotification to be posted (as will any change caused by reading new values from disk), so your application can keep track of changes made to the defaults by other software.
NB. The GNUstep implementation differs from the Apple one in that it is thread-safe while Apple's (as of MacOS-X 10.1) is not.
Method summary
Resets the shared user defaults object to reflect
the current user ID. Needed by setuid processes which
change the user they are running as.
In
GNUstep you should call
GSSetUserName()
when changing your effective user ID, and that class
will call this function for you.
Sets the array of user languages preferences. Places the specified array in the NSLanguages user default.
Returns the shared defaults object. If it doesn't exist yet, it's created. The defaults are initialized for the current user. The search list is guaranteed to be standard only the first time this method is invoked. The shared instance is provided as a convenience; other instances may also be created.
Returns the array of user languages preferences. Uses the NSLanguages user default if available, otherwise tries to infer setup from operating system information etc (in particular, uses the LANGUAGES environment variable).
Adds the domain names aName to the search
list of the receiver.
The domain is added after
the application domain.
Suites may be removed
using the
-removeSuiteNamed:
method.
Looks up a value for a specified default using
-objectForKey:
and checks that it is an NSArray object. Returns
nil
if it is not.
Looks up a value for a specified default using
-objectForKey:
and returns its boolean representation.
Returns
NO
if it is not a boolean.
The
text 'yes' or 'true' or any non zero numeric value is
considered to be a boolean YES
.
Other string values are NO
.
NB.
This differs slightly from the documented behavior for
MacOS-X (August 2002) in that the GNUstep version
accepts the string 'TRUE' as equivalent to 'YES'.
Looks up a value for a specified default using
-objectForKey:
and checks that it is an NSData object. Returns
nil
if it is not.
Looks up a value for a specified default using
-objectForKey:
and checks that it is an NSDictionary object. Returns
nil
if it is not.
Returns a dictionary representing the current state of the defaults system... this is a merged version of all the domains in the search list.
Looks up a value for a specified default using -objectForKey: and checks that it is a float. Returns 0.0 if it is not.
Initializes defaults for current user calling initWithUser:
Initializes defaults for the specified path. Returns an object with an empty search list.
Initializes defaults for the specified user calling -initWithContentsOfFile:
Looks up a value for a specified default using -objectForKey: and checks that it is an integer. Returns 0 if it is not.
Looks up a value for a specified default using. The
lookup is performed by accessing the domains in the
order given in the search list.
Returns
nil
if defaultName cannot be
found.
Returns the persistent domain specified by domainName.
Returns an array listing the name of all the persistent domains.
Merges the contents of the dictionary newVals into the registration domain. Registration defaults may be added to or replaced using this method, but may never be removed. Thus, setting registration defaults at any point in your program guarantees that the defaults will be available thereafter.
Removes the default with the specified name from the application domain.
Removes the persistent domain specified by
domainName from the user defaults.
Causes a NSUserDefaultsDidChangeNotification to be
posted if this is the first change to a
persistent-domain since the last
-synchronize
.
Removes the named domain from the serach list of
the receiver.
Suites may be added using the
-addSuiteNamed:
method.
Removes the volatile domain specified by domainName from the user defaults.
Returns an array listing the domains searched in order to look up a value in the defaults system. The order of the names in the array is the order in which the domains are searched.
Sets a boolean value for
defaultName in the application domain.
The boolean value is stored as a
string - either YES
or NO
.
Calls
-setObject:forKey:
to make the change.
Sets a float value for
defaultName in the application domain.
Calls
-setObject:forKey:
to make the change.
Sets an integer value for
defaultName in the application domain.
Calls
-setObject:forKey:
to make the change.
Sets an object value for
defaultName in the application domain.
The defaultName must be a
non-empty string.
The value
must be an instance of one of the
[NSString -propertyList]
classes.
Causes a NSUserDefaultsDidChangeNotification to be posted if this is the first change to a persistent-domain since the last -synchronize .
If value is nil
, this is
equivalent to the
-removeObjectForKey:
method.
Replaces the persistent-domain specified by
domainName with domain... a
dictionary containing keys and defaults values.
Raises an NSInvalidArgumentException if
domainName already exists as a
volatile-domain.
Causes a
NSUserDefaultsDidChangeNotification
to be posted if this is the first change to a
persistent-domain since the last
-synchronize
.
Sets the list of the domains searched in order to look
up a value in the defaults system. The order of the
names in the array is the order in which the domains
are searched.
On lookup, the first match is
used.
Sets the volatile-domain specified by
domainName to domain... a
dictionary containing keys and defaults values.
Raises an NSInvalidArgumentException if
domainName already exists as either a
volatile-domain or a persistent-domain.
Calls
-arrayForKey:
to get an array value for defaultName and
checks that the array contents are string objects...
if not, returns nil
.
Looks up a value for a specified default using
-objectForKey:
and checks that it is an NSString. Returns
nil
if it is not.
Ensures that the in-memory and on-disk
representations of the defaults are in
sync. You may call this yourself, but probably don't
need to since it is invoked at intervals whenever a
runloop is running.
If any persistent domain
is changed by reading new values from disk, an
NSUserDefaultsDidChangeNotification
is posted.
Returns the volatile domain specified by domainName.
Returns an array listing the name of all the volatile domains.