| Inherits from | |
| Conforms to | |
| Framework | /System/Library/Frameworks/Foundation.framework |
| Availability | Available in Mac OS X v10.2 and later. |
| Companion guide | |
| Declared in | NSKeyedArchiver.h |
| Related sample code |
NSKeyedArchiver, a concrete subclass of NSCoder, provides a way to encode objects (and scalar values) into an architecture-independent format that can be stored in a file. When you archive a set of objects, the class information and instance variables for each object are written to the archive. NSKeyedArchiver’s companion class, NSKeyedUnarchiver, decodes the data in an archive and creates a set of objects equivalent to the original set.
A keyed archive differs from a non-keyed archive in that all the objects and values encoded into the archive are given names, or keys. When decoding a non-keyed archive, values have to be decoded in the same order in which they were encoded. When decoding a keyed archive, because values are requested by name, values can be decoded out of sequence or not at all. Keyed archives, therefore, provide better support for forward and backward compatibility.
The keys given to encoded values must be unique only within the scope of the current object being encoded. A keyed archive is hierarchical, so the keys used by object A to encode its instance variables do not conflict with the keys used by object B, even if A and B are instances of the same class. Within a single object, however, the keys used by a subclass can conflict with keys used in its superclasses.
An NSArchiver object can write the archive data to a file or to a mutable-data object (an instance of NSMutableData) that you provide.
+ archivedDataWithRootObject:
+ archiveRootObject:toFile:
– finishEncoding
– outputFormat
– setOutputFormat:
– encodeBool:forKey:
– encodeBytes:length:forKey:
– encodeConditionalObject:forKey:
– encodeDouble:forKey:
– encodeFloat:forKey:
– encodeInt:forKey:
– encodeInt32:forKey:
– encodeInt64:forKey:
– encodeObject:forKey:
Returns an NSData object containing the encoded form of the object graph whose root object is given.
+ (NSData *)archivedDataWithRootObject:(id)rootObject
The root of the object graph to archive.
An NSData object containing the encoded form of the object graph whose root object is rootObject. The format of the archive is NSPropertyListBinaryFormat_v1_0.
NSKeyedArchiver.hArchives an object graph rooted at a given object by encoding it into a data object then atomically writes the resulting data object to a file at a given path, and returns a Boolean value that indicates whether the operation was successful.
+ (BOOL)archiveRootObject:(id)rootObject toFile:(NSString *)path
The root of the object graph to archive.
The path of the file in which to write the archive.
YES if the operation was successful, otherwise NO.
The format of the archive is NSPropertyListBinaryFormat_v1_0.
NSKeyedArchiver.hReturns the class name with which NSKeyedArchiver encodes instances of a given class.
+ (NSString *)classNameForClass:(Class)cls
The class for which to determine the translation mapping.
The class name with which NSKeyedArchiver encodes instances of cls. Returns nil if NSKeyedArchiver does not have a translation mapping for cls.
NSKeyedArchiver.hAdds a class translation mapping to NSKeyedArchiver whereby instances of of a given class are encoded with a given class name instead of their real class names.
+ (void)setClassName:(NSString *)codedName forClass:(Class)cls
The name of the class that NSKeyedArchiver uses in place of cls.
The class for which to set up a translation mapping.
When encoding, the class’s translation mapping is used only if no translation is found first in an instance’s separate translation map.
NSKeyedArchiver.hReturns the class name with which the receiver encodes instances of a given class.
- (NSString *)classNameForClass:(Class)cls
The class for which to determine the translation mapping.
The class name with which the receiver encodes instances of cls. Returns nil if the receiver does not have a translation mapping for cls. The class’s separate translation map is not searched.
NSKeyedArchiver.hReturns the receiver’s delegate.
- (id < NSKeyedArchiverDelegate >)delegate
The receiver's delegate.
NSKeyedArchiver.hEncodes a given Boolean value and associates it with a given key.
- (void)encodeBool:(BOOL)boolv forKey:(NSString *)key
The value to encode.
The key with which to associate boolv. This value must not be nil.
decodeBoolForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a given number of bytes from a given C array of bytes and associates them with the a given key.
- (void)encodeBytes:(const uint8_t *)bytesp length:(NSUInteger)lenv forKey:(NSString *)key
A C array of bytes to encode.
The number of bytes from bytesp to encode.
The key with which to associate the encoded value. This value must not be nil.
decodeBytesForKey:returnedLength: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a reference to a given object and associates it with a given key only if it has been unconditionally encoded elsewhere in the archive with encodeObject:forKey:.
- (void)encodeConditionalObject:(id)objv forKey:(NSString *)key
The object to encode.
The key with which to associate the encoded value. This value must not be nil.
NSKeyedArchiver.hEncodes a given double value and associates it with a given key.
- (void)encodeDouble:(double)realv forKey:(NSString *)key
The value to encode.
The key with which to associate realv. This value must not be nil.
decodeDoubleForKey: (NSKeyedUnarchiver)decodeFloatForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a given float value and associates it with a given key.
- (void)encodeFloat:(float)realv forKey:(NSString *)key
The value to encode.
The key with which to associate realv. This value must not be nil.
decodeFloatForKey: (NSKeyedUnarchiver)decodeDoubleForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a given 32-bit integer value and associates it with a given key.
- (void)encodeInt32:(int32_t)intv forKey:(NSString *)key
The value to encode.
The key with which to associate intv. This value must not be nil.
decodeInt32ForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a given 64-bit integer value and associates it with a given key.
- (void)encodeInt64:(int64_t)intv forKey:(NSString *)key
The value to encode.
The key with which to associate intv. This value must not be nil.
decodeInt64ForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a given int value and associates it with a given key.
- (void)encodeInt:(int)intv forKey:(NSString *)key
The value to encode.
The key with which to associate intv. This value must not be nil.
decodeIntForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hEncodes a given object and associates it with a given key.
- (void)encodeObject:(id)objv forKey:(NSString *)key
The value to encode. This value may be nil.
The key with which to associate objv. This value must not be nil.
decodeObjectForKey: (NSKeyedUnarchiver)NSKeyedArchiver.hInstructs the receiver to construct the final data stream.
- (void)finishEncoding
No more values can be encoded after this method is called. You must call this method when finished.
NSKeyedArchiver.hReturns the receiver, initialized for encoding an archive into a given a mutable-data object.
- (id)initForWritingWithMutableData:(NSMutableData *)data
The mutable-data object into which the archive is written.
The receiver, initialized for encoding an archive into data.
When you finish encoding data, you must invoke finishEncoding at which point data is filled. The format of the receiver is NSPropertyListBinaryFormat_v1_0.
NSKeyedArchiver.hReturns the format in which the receiver encodes its data.
- (NSPropertyListFormat)outputFormat
The format in which the receiver encodes its data. The available formats are NSPropertyListXMLFormat_v1_0 and NSPropertyListBinaryFormat_v1_0.
NSKeyedArchiver.hAdds a class translation mapping to the receiver whereby instances of of a given class are encoded with a given class name instead of their real class names.
- (void)setClassName:(NSString *)codedName forClass:(Class)cls
The name of the class that the receiver uses uses in place of cls.
The class for which to set up a translation mapping.
When encoding, the receiver’s translation map overrides any translation that may also be present in the class’s map.
NSKeyedArchiver.hSets the delegate for the receiver.
- (void)setDelegate:(id < NSKeyedArchiverDelegate >)delegate
The delegate for the receiver.
NSKeyedArchiver.hSets the format in which the receiver encodes its data.
- (void)setOutputFormat:(NSPropertyListFormat)format
The format in which the receiver encodes its data. format can be NSPropertyListXMLFormat_v1_0 or NSPropertyListBinaryFormat_v1_0.
NSKeyedArchiver.hNames of exceptions that are raised by NSKeyedArchiver if there is a problem creating an archive.
extern NSString *NSInvalidArchiveOperationException;
NSInvalidArchiveOperationExceptionThe name of the exception raised by NSKeyedArchiver if there is a problem creating an archive.
Available in Mac OS X v10.2 and later.
Declared in NSKeyedArchiver.h.
NSKeyedArchiver.hLast updated: 2009-04-15
Mac OS X Reference Library Data Management: File Management NSKeyedArchiver Class Reference