数据存取之归档

 - (IBAction)savebtn:(id)sender {

//    GYLPerson * p = [[GYLPerson alloc]init];

//    p.name = @"guoyule";

//    p.age = 24;

//    p.hight = 178.0f;

    GYLStudent * stu = [[GYLStudent alloc]init];

    stu.name = @"guoyule";

    stu.age = 24;

    stu.hight = 178.0f;

    stu.email = @"[e-mail]";

    

    //2.获取文件路径

    NSString * docPath = [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory , NSUserDomainMask , YES) lastObject];

    //尾加文件名

    NSString * path = [docPath stringByAppendingString:@"guoyule.arc"];

    NSLog(@"path = %@",path);

//    3.将自己定义的对象保存到文件中

    [NSKeyedArchiver archiveRootObject:stu toFile:path];

    

    

}

- (IBAction)readBtn:(id)sender {

    NSString * docPth = [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory,NSUserDomainMask,YES) lastObject];

    NSString * path = [docPth stringByAppendingString:@"guoyule.arc"];

//    2.从文件中读取对象

    GYLStudent * guo = [NSKeyedUnarchiver unarchiveObjectWithFile:path];

    NSLog(@"%@,%d,%.1f,%@",guo.name,guo.age,guo.hight,guo.email);

}

在使用继承的时候 一定要让父类使用    [super encodeWithCoder:aCoder];

@class GYLStudent,GYLPerson;

-(void)encodeWithCoder:(NSCoder *)aCoder

{

    [super encodeWithCoder:aCoder];

    NSLog(@"GYLStudent encodeWithCoder");

    [aCoder encodeObject:self.email forKey:@"email"];

    

}

-(id)initWithCoder:(NSCoder *)aDecoder

{

    if (self = [super initWithCoder:aDecoder]) {

        NSLog(@"GYLStudent initWithCoder");

        self.email = [aDecoder decodeObjectForKey:@"email"];

    }

    return self;

}