用runtime封装归档(encoding)

runtime一套比较基层的c语言的API(库)

归档(OC对象-->字典—>2进制—>写入沙盒 || 目的.数据持久化)

 

#import <UIKit/UIKit.h>
//遵循协议
@interface NSObject (Coding)<NSCoding>
@end

 

 

#import "NSObject+Coding.h"
#import <objc/runtime.h>

@implementation NSObject (Coding)

//归档必须实现的方法
- (void)encodeWithCoder:(NSCoder *)coder
{
    //属性个数
    unsigned int count = 0;
    //拷贝所有成员的属性,传count的地址,count的值会改变,传值和传地址的区别
    Ivar * ivars = class_copyIvarList([self class], &count);
    for (int i = 0; i < count; i++) {
        // 从列表中取出属性,在c语言中指针就相当于数组
        Ivar ivar = ivars[i];
        //取出名称
        const char * name = ivar_getName(ivar);
        //转NSString,取出key
        NSString *key = [NSString stringWithUTF8String:name];
        //kvc取值value,归档
        [coder encodeObject:[self valueForKey:key] forKey:key];
    }
    //在C语言中,只要用到copy就会有指针泄露,所以要释放指针
    free(ivars);
}

//解挡
- (instancetype)initWithCoder:(NSCoder *)coder
{
    if (self = [self init]) {
        //解档
        unsigned int count = 0;
        //copy所有属性
        Ivar * ivars = class_copyIvarList([self class], &count);
        for (int i = 0;  i < count; i++) {
            //取属性
            Ivar ivar = ivars[i];
            //取name
            const char * name = ivar_getName(ivar);
            //转NSString
            NSString *key = [NSString stringWithUTF8String:name];
            //解挡
            id value = [coder decodeObjectForKey:key];
            //设置到自己的属性上去
            [self setValue:value forKey:key];
        }
        //释放指针
               free(ivars);
    }
    return self;
}

@end
用的时候直接建这样一对category文件,用的时候直接把头文件导进去就可以了