数据存储值归档Archive

Posted 2020-09-22 gavanwanggw

tags:

篇首语：本文由小常识网(cha138.com)小编为大家整理，主要介绍了数据存储值归档Archive相关的知识，希望对你有一定的参考价值。

先比較一下各个数据存储之间的关系：

技术分享

关于归档。是ios中的shu‘j数据存储中的一种数据存储方式。以下了解一下归档中的一个实例：

以下的是父类person
#import <Foundation/Foundation.h>

@interface Person : NSObject <NSCoding>
@property (nonatomic,copy) NSString *name;
@property (nonatomic,assign) int age;
@property (nonatomic,assign ) BOOL sex;
@property (nonatomic,assign) float height;
@property (nonatomic,assign) double weight;
@end

#import "Person.h"

@implementation Person

//有存必然是有取。所以存是为了取
- (id)initWithCoder:(NSCoder *)aDecoder{
    
    self = [super init];
    
    if (self) {
        NSLog(@"存在");
        self.name =   [aDecoder decodeObjectForKey:@"name"];
        self.age = [aDecoder decodeInt32ForKey:@"age"];
        self.sex = [aDecoder decodeBoolForKey:@"sex"];
        self.height = [aDecoder decodeFloatForKey:@"height"];
        self.weight = [aDecoder decodeDoubleForKey:@"weight"];
    }
    return self;
}

-(void)encodeWithCoder:(NSCoder *)aCoder{

    //有文件就能够看出编码的是一个方式编码
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeInt:self.age forKey:@"age"];
    [aCoder encodeBool:self.sex forKey:@"sex"];
    [aCoder encodeFloat:self.height forKey:@"height"];
    [aCoder encodeDouble:self.weight forKey:@"weight"];

}
@end

子类student继承person类：

#import <Foundation/Foundation.h>
#include "Person.h"

@interface Student : Person

@property (nonatomic,copy )NSString * content;
@property (nonatomic,assign ) float grade;

@end
#import "Student.h"

@implementation Student

//有存必然是有取，所以存是为了取
- (id)initWithCoder:(NSCoder *)aDecoder{

    if (self = [super initWithCoder:aDecoder]) {
        NSLog(@"存在");
        self.content =   [aDecoder decodeObjectForKey:@"content"];
        self.grade = [aDecoder decodeFloatForKey:@"grade"];
            }
    return self;
}

-(void)encodeWithCoder:(NSCoder *)aCoder{
    
    [super encodeWithCoder:aCoder];
    //有文件就能够看出编码的是一个方式编码
    [aCoder encodeObject:self.content forKey:@"content"];
    [aCoder encodeFloat:self.grade forKey:@"grade"];

}

@end

以下是在ViewController中中对数据通过两button对数据进归档和解归档

#import "ViewController.h"
#import "Person.h"
#import "Student.h"

@interface ViewController ()
//分别室保存和获取的两个button
- (IBAction)saveArchive:(id)sender;
- (IBAction)obtainUnarchive:(id)sender;
@end

@implementation ViewController
- (void)viewDidLoad {
    [super viewDidLoad];
}

//保存数据
- (IBAction)saveArchive:(id)sender {
    
    NSLog(@"開始编码归档而且保存");
    //归档需要要素：1、保存对象 2、保存的文件文件夹 3、保存管理器（归档器）

    //获取要保存的对象，对象必需要幼稚等等
//    Person *person = [[Person alloc]init];
//    person.age = 18;
//    person.name = @"linyu";
//    person.sex = YES; //表示为男的
//    person.height = 180;
//    person.weight = 60;
    
    Student *stu = [[Student alloc]init];
    stu.age = 18;
    stu.name = @"linyu";
    stu.sex = YES;
    stu.height = 180;
    stu.weight = 60;
    stu.content = @"I am a student !";
    stu.grade = 98.9;

    //获取要保存文件的路径
    NSString *documentDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString * dir = [documentDir stringByAppendingString:@"doc.txt"];
    NSLog(@"%@",dir);
    [NSKeyedArchiver archiveRootObject:stu toFile:dir];
}

//获取数据
- (IBAction)obtainUnarchive:(id)sender {
    //获取归档之后的内容、
    NSLog(@"获取内容");
    NSString *documentDir = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
    NSString * dir = [documentDir stringByAppendingString:@"doc.txt"];
    Student *per = [NSKeyedUnarchiver unarchiveObjectWithFile:dir];
    NSLog(@"%@",dir);
    NSLog(@"%@ %d %d %.2f %.2f %.2f %@",per.name,per.age,per.sex,per.height,per.weight,per.grade,per.content);
}
@end

输出的结果：

技术分享