复杂对象无法象 NSString,NSArray等简单对象一样直接通过 writeToFile 实现持久化,当对复杂对象进行持久化时需要将其转化为 NSData (归档),但获取数据时,将 NSData 转化为复杂对象 (反归档)
下面通过一个简单的 Person 类实现归档和反归档:
1.新建 Peoson 类,有两个属性 name,age,其需要遵守 <NSCoding> 协议,实现- (void)encodeWithCoder: 和 - (instancetype)initWithCoder: 方法
代码:
1 // 2 // Person.m 3 // UILesson18_archiver 4 // 5 // Created by Ager on 15/11/5. 6 // Copyright © 2015年 Ager. All rights reserved. 7 // 8 9 #import "Person.h"10 11 @implementation Person12 13 //对属性做归档处理14 - (void)encodeWithCoder:(NSCoder *)aCoder{15 16 [aCoder encodeObject:self.name forKey:@"name"];17 [aCoder encodeInteger: self.age forKey:@"age"];18 19 }20 21 //反归档处理22 - (instancetype)initWithCoder:(NSCoder *)aDecoder{23 24 if (self = [super init]) {25 self.name = [aDecoder decodeObjectForKey:@"name"];26 self.age = [aDecoder decodeIntegerForKey:@"age"];27 }28 return self;29 }30 31 @end
2.完成归档,实现本地存储:(NSKeyedArchiver)
代码:
1 //归档 2 NSMutableData *data = [NSMutableData data]; 3 NSKeyedArchiver *keyed = [[NSKeyedArchiver alloc]initForWritingWithMutableData:data]; 4 [keyed encodeObject:per forKey:@"per"]; 5 //结束归档 6 [keyed finishEncoding]; 7 //归档结束,存数据 8 NSString *cachesPath = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES)[0]; 9 10 NSLog(@"%@",cachesPath);11 12 NSString *newPath = [cachesPath stringByAppendingPathComponent:@"person"];13 [data writeToFile:newPath atomically:YES];
3.完成反归档,获取复杂对象:(NSKeyedUnarchiver)
代码:
1 //反归档2 NSData *data1 = [NSData dataWithContentsOfFile:newPath];3 NSKeyedUnarchiver *unKeyed = [[NSKeyedUnarchiver alloc]initForReadingWithData:data1];4 5 Person *per1 = [unKeyed decodeObjectForKey:@"per"];6 [unKeyed finishDecoding];7 NSLog(@"%@ %ld",per1.name,per1.age);