归档和解档

- (void)encodeWithCoder:(NSCoder *)aCoder {
    unsigned int count;
    Ivar *ivar = class_copyIvarList([self class], &count);
    for (int i = 0; i < count; i++) {
        Ivar iv = ivar[i];
        const char *name = ivar_getName(iv);
        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 != nil) {
        unsigned int count = 0;
        Ivar *ivar = class_copyIvarList([self class], &count);
        for (int i = 0; i < count; i++) {
            Ivar var = ivar[i];
            const char *keyName = ivar_getName(var);
            NSString *key = [NSString stringWithUTF8String:keyName];
            id value = [aDecoder decodeObjectForKey:key];
            [self setValue:value forKey:key];
        }
        free(ivar);
    }
    return self;
}