归档与反归档

一.归档操作

NSArray *array =
@[@"归档",@"反归档",@"开始”];

//1.创建归档对象

NSMutableData *data = [NSMutableData
data];

NSKeyedArchiver *archiver = [[NSKeyedArchiver
alloc]  initForWritingWithMutableData:data];

//2.归档

[archiver encodeObject:per
forKey:@"array"];

//3.结束归档,当结束归档之后,再归档无效

[archiver finishEncoding];

[array release];

[archiver release];

//4.获取写入文件路径,没有会自动创建一个

NSString *documentPath =

[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,
YES)firstObject];

NSString *newFiel = [documentPath
stringByAppendingPathComponent:@"bb.txt"];

//5.data写入文件

BOOL isSucceed = [data
writeToFile:[self
getFiel]
atomically:YES];

二.反归档操作

//1.根据文件路径初始化NSMutableData

NSMutableData *Data = [NSMutableData
dataWithContentsOfFile:/Users/lanouhn/Library/Application Support/iPhone Simulator/7.1/Applications/300BEFD5-1F93-47A3-A1B3-936195FAA53F];

//2.创建一个反归档类

NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver
alloc]
initForReadingWithData:Data];

//3.反归档

NSArray *array  = [unarchiver
decodeObjectForKey:@"array"];

//4.结束反归档

[unarchiver finishDecoding];

[unarchiver release];

三 .注意

1.如果要对一个类的对象实现归档操作,必须让该类实现NSCoding协议

2.当对象为字符串,数组,字典,集合时,属性的语义特性声明为copy.

3.定义完属性的在给实例变量赋值时,要使用setter方法.

如下例

@interface Person : NSObject<NSCoding]]>

@property (nonatomic , copy)NSString *name