1.什么是 归档 和 解档
数据本地存储持久化的一种。
归档：对象的序列化，通过某种格式把对象保存成本地文件。
解档：反序列化，把归档的对象文件读成原来的对象。
2.具体过程
- 在归档对象的
.h中遵循规定协议<NSCoding>
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface Person : NSObject<NSCoding>
@property (nonatomic,copy)NSString *name;
@property (nonatomic,copy)NSString *age;
@property (nonatomic,copy)NSString *number;
@end
NS_ASSUME_NONNULL_END
- 在归档对象的
.m中实现协议方法
#import "Person.h"
@implementation Person
- (NSString *)description{
return [NSString stringWithFormat:@"%@\n%@\n%@",_name,_age,_number];
}
- (void)encodeWithCoder:(NSCoder *)aCoder{
// 告诉系统归档的属性是哪些
[aCoder encodeObject:self.name forKey:@"name"];
[aCoder encodeObject:self.age forKey:@"age"];
[aCoder encodeObject:self.number forKey:@"number"];
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder{
self = [super init];
if (self) {
// 解档
self.name = [aDecoder decodeObjectForKey:@"name"];
self.age = [aDecoder decodeObjectForKey:@"age"];
self.number = [aDecoder decodeObjectForKey:@"number"];
}
return self;
}
@end
- 在
vc中进行存取操作（以temp路径为例）
（1）归档过程
Person *p = [[Person alloc] init];
p.name = @"wxh";
p.age = @"18岁";
p.number = @"23号";
NSString *filePath = NSTemporaryDirectory();
NSString *uniquePath = [filePath stringByAppendingPathComponent:@"p_wxh.plist"];
[NSKeyedArchiver archiveRootObject:p toFile:uniquePath];
（2）解档过程
NSString *filePath = NSTemporaryDirectory();
NSString *uniquePath = [filePath stringByAppendingPathComponent:@"p_wxh.plist"];
Person *p = [NSKeyedUnarchiver unarchiveObjectWithFile:uniquePath];
NSLog(@"%@",p);
（3）删除文件
- (void)deleteFileWithFileName:(NSString *)fileName filePath:(NSString *)filePath {
//创建文件管理对象
NSFileManager* fileManager = [NSFileManager defaultManager];
//获取文件目录
if (!filePath) {
//如果文件目录设置有空,默认删除Cache目录下的文件
filePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];
}
//拼接文件名
NSString *uniquePath=[filePath stringByAppendingPathComponent:[NSString stringWithFormat:@"%@",fileName]];
//文件是否存在
BOOL blHave=[[NSFileManager defaultManager] fileExistsAtPath:uniquePath];
//进行逻辑判断
if (!blHave) {
NSLog(@"文件不存在");
return ;
}
else {
// 文件是否被删除
BOOL blDele= [fileManager removeItemAtPath:uniquePath error:nil];
// 进行逻辑判断
if (blDele) {
NSLog(@"删除成功");
}
else {
NSLog(@"删除失败");
}
}
}
（4）获取文件路径有三种方法
// 获取沙盒Document路径
filePath = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) firstObject];
// 获取沙盒temp路径
filePath = NSTemporaryDirectory();
// 获取沙盒Cache路径
filePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) firstObject];
// 文件路径
NSString *uniquePath = [filePath stringByAppendingPathComponent:你的文件名称];
3.使用runtime
当在归档对象.m中实现协议方法时，如果对象的属性比较多，这个时候就会很繁琐。那么可以利用runtime获取属性，简化过程。
#import "Person.h"
#import <objc/runtime.h>
@implementation Person
- (NSString *)description{
unsigned int count;
Ivar *ivar = class_copyIvarList([self class], &count);
NSString *descString = @"打印:";
for (int i = 0; i<count; i++) {
Ivar iva = ivar[i];
const char *name = ivar_getName(iva);
NSString *strName = [NSString stringWithUTF8String:name];
//利用KVC取值
id value = [self valueForKey:strName];
descString = [NSString stringWithFormat:@"%@\n%@",descString,value];
}
free(ivar);
return descString;
}
- (void)encodeWithCoder:(NSCoder *)aCoder{
unsigned int count;
Ivar *ivar = class_copyIvarList([self class], &count);
for (int i = 0; i<count; i++) {
Ivar iva = ivar[i];
const char *name = ivar_getName(iva);
NSString *strName = [NSString stringWithUTF8String:name];
//利用KVC取值
id value = [self valueForKey:strName];
[aCoder encodeObject:value forKey:strName];
}
free(ivar);
}
- (instancetype)initWithCoder:(NSCoder *)aDecoder{
self = [super init];
if (self) {
unsigned int count = 0;
Ivar *ivar = class_copyIvarList([self class], &count);
for (int i = 0; i < count; i++) {
Ivar iva = ivar[i];
const char *name = ivar_getName(iva);
NSString *strName = [NSString stringWithUTF8String:name];
//进行解档取值
id value = [aDecoder decodeObjectForKey:strName];
//利用KVC对属性赋值
[self setValue:value forKey:strName];
}
free(ivar);
}
return self;
}
@end
