【深入学习iOS开发（五）】Archive（归档）

Dear 丶 2022-01-05 19:45 191阅读 0赞

**Archive（归档）**

Archives provide a means to convert objects and values into an architecture-independent stream of bytes that preserves the identity of and the relationships between the objects and values.

**1、归档与解档**

**Archive**

RootObject

[NSKeyedArchiver archiveRootObject:[contentTextField text] toFile:[self archiveFilePath]];

Keyed

NSString *content = [contentTextField text];
    NSMutableData *data = [NSMutableData data];
    NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
    [archiver encodeObject:content forKey:@"content"];
    [archiver finishEncoding];
    [data writeToFile:[self archiveFilePath] atomically:YES];

**Unarchive**

Root Object

[contentLabel setText:[NSKeyedUnarchiver unarchiveObjectWithFile:[self archiveFilePath]]];

Keyed

NSData *data = [NSData dataWithContentsOfFile:[self archiveFilePath]];
    NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
    [contentLabel setText:[unarchiver decodeObjectForKey:@"content"]];
    [unarchiver finishDecoding];

**2、NSCoding Protocol**

为了支持编码（encoding）和解码（decoding），类需要实现NSCoding Protocol。

以类Person为例：

Person.h

#import <Foundation/Foundation.h>
    
    #define PERSON_KEY_FIRSTNAME @"FIRSTNAME"
    #define PERSON_KEY_LASTNAME @"LASTNAME"
    #define PERSON_KEY_HEIGHT @"HEIGHT"
    
    @interface Person : NSObject <NSCoding>
    
    @property (nonatomic, retain) NSString *firstName;
    @property (nonatomic, retain) NSString *lastName;
    @property (nonatomic, assign) float height;
    
    @end

Person.m

#import "Person.h"
    
    @implementation Person
    
    @synthesize firstName, lastName, height;
    
    - (void)encodeWithCoder:(NSCoder *)aCoder {
        [aCoder encodeObject:self.firstName forKey:PERSON_KEY_FIRSTNAME];
        [aCoder encodeObject:self.lastName forKey:PERSON_KEY_LASTNAME];
        [aCoder encodeFloat:self.height forKey:PERSON_KEY_HEIGHT];
    }
    
    - (id)initWithCoder:(NSCoder *)aDecoder {
        self = [super init];
        if (self != nil) {
            self.firstName = [aDecoder decodeObjectForKey:PERSON_KEY_FIRSTNAME];
            self.lastName = [aDecoder decodeObjectForKey:PERSON_KEY_LASTNAME];
            self.height = [aDecoder decodeFloatForKey:PERSON_KEY_HEIGHT];
        }
        return self;
    }
    
    @end

参考：[https://developer.apple.com/library/ios/\#documentation/Cocoa/Conceptual/Archiving/Archiving.html][https_developer.apple.com_library_ios_documentation_Cocoa_Conceptual_Archiving_Archiving.html]

转载于:https://www.cnblogs.com/dyingbleed/archive/2013/05/02/3054058.html

[https_developer.apple.com_library_ios_documentation_Cocoa_Conceptual_Archiving_Archiving.html]: https://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/Archiving/Archiving.html