NSKeyedArchiver编码器

约定不等于承诺〃 2023-10-17 05:26 32阅读 0赞

ViewController.m文件

- (void)viewDidLoad {
        [super viewDidLoad];
        NSLog(@"%@",NSHomeDirectory());
        NSData *data = [NSData dataWithContentsOfFile:[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/peopleFile.plist"]];
            //NSKeyedUnarchiver解码器，能够把二进制数据解码为对象。
        People *p = [NSKeyedUnarchiver unarchiveObjectWithData:data];
        NSLog(@"%@",p);
    }
    
    - (IBAction)savePeopleClick:(UIButton *)sender {
        
        People *p1 = [[People alloc] init];
        p1.name = @"张三";
        p1.age = 34;
        p1.sex = YES;
        
            //NSUserDefaults中只能存储系统自带的数据类
            //[[NSUserDefaults standardUserDefaults] setObject:p1 forKey:@"people"];
    
            //只有数组中存储的对象是系统自带的数据类(NSString,NSArray,NSNumber,NSDate)时，数组才可以writoFile.
    //    NSArray *array = [NSArray arrayWithObject:p1];
    //    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/arrayFile.plist"];
    //    if ([array writeToFile:path atomically:NO]) {
    //        NSLog(@"存储成功");
    //    }else {
    //        NSLog(@"存储失败");
    //    }
        
            //NSData数据类，表示一段二进制数据。
            //对于自定义的类，要想存入文件，必须把对象转换为二进制数据。就必须实现NSCoding协议。(对象序列化)
        
            //NSKeyedArchiver,编码器，能够把一个对象转换为二进制数据（前提是这个对象实现了NSCoding协议）
        NSData *data = [NSKeyedArchiver archivedDataWithRootObject:p1];
            //二进制数据可以直接写入文件
        [data writeToFile:[NSHomeDirectory() stringByAppendingPathComponent:@"Documents/peopleFile.plist"] atomically:NO];
    }

People.h

//只有声明并实现了NSCoding的类才能被转换为二进制数据。
    @interface People : NSObject<NSCoding>
    
    @property (nonatomic,copy)NSString *name;
    @property (nonatomic,assign)NSInteger age;
    @property (nonatomic,assign)BOOL sex;

People.m

- (void)dealloc{
            //[_name release];
        self.name = nil;
        [super dealloc];
    }
    
        //编码方法,方法中要把需要编码的属性进行编码。
    - (void)encodeWithCoder:(NSCoder *)aCoder{
        [aCoder encodeObject:_name forKey:@"name"];
        [aCoder encodeInteger:_age forKey:@"age"];
        [aCoder encodeBool:_sex forKey:@"sex"];
    }
        //解码方法，把每个属性进行解码
    - (id)initWithCoder:(NSCoder *)aDecoder{
        self = [super init];
        if (self) {
                //self.name = [aDecoder decodeObjectForKey:@"name"];
            _name = [[aDecoder decodeObjectForKey:@"name"] copy];
            _age = [aDecoder decodeIntegerForKey:@"age"];
            _sex = [aDecoder decodeBoolForKey:@"sex"];
        }
        return self;
    }
    
    - (NSString *)description{
        return [NSString stringWithFormat:@"%@,%lu,%@",_name,_age,_sex?@"男":@"女"];
    }

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