IOS初级：NSKeyedArchiver

NSKeyedArchiver对象归档

首先要实现<NScoding>里面的两个代理方法initWithCoder,encodeWithCoder
@property (nonatomic, copy) NSString *keyName;
/*
    将某个对象写入文件时候会调用
    在这个方法中说清楚哪些属性需要存储
 */
- (void)encodeWithCoder:(NSCoder *)encoder{
    [encoder encodeObject:self.keyName forKey:@"KeyName"];
}
/*
    解析对象会调用这个方法
    需要解析哪些属性
 */
- (id)initWithCoder:(NSCoder *)decoder{
    if (self = [super init]) {
        self.name = [decoder decodeObjectForKey:@"KeyName"];
    }
    return self;
}

//宏定义一个数据存储路径
#define MyDataFilePath [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"myApp.data"]

@property (nonatomic, strong) NSMutableArray *myAppArr;
//从归档提取数据
_myAppArr = [NSKeyedUnarchiver unarchiveObjectWithFile:MyDataFilePath];

//将数据归档保存
[NSKeyedArchiver archiveRootObject:self.myAppArr toFile:MyDataFilePath];