缓存

存储缓存：第三方应用只能把信息保存在应用程序的沙盒中，因为缓存数据不是用户产生，所以应该将其保存在NSCahcesDictionary中而不是NSDocumentsDirectory中。因为把缓存存储在缓存文件夹下的原因是iCloud（和iTunes）的备份不包括此目录。如果放在了Documents目录下创建的大缓存将备份到iCloud的有限空间中。
 *  序列化数据
 *  以keyValue形式对基本数据类型Encoding
 */
-(void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:_title forKey:@"title"];
    [aCoder encodeObject:_content forKey:@"content"];
    [aCoder encodeObject:_modelId forKey:@"modelId"];
}

/**
 *  反序列化数据
 *  以keyValue形式对基本数据类型Decoding,返回数据模型本身
 */
-(id)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super init]) {
        NSLog(@"----> %s",__FUNCTION__);
        self.title = [aDecoder decodeObjectForKey:@"title"];
        self.content = [aDecoder decodeObjectForKey:@"content"];
        self.modelId = [aDecoder decodeObjectForKey:@"modelId"];
    }
    return self;
}

    for ( int i = 0;  i < 10; i++) {
        model= [[ZQModel alloc] init];
        model.title = [NSString stringWithFormat:@"title%d",i];
        model.content = [NSString stringWithFormat:@"content%d",i];
        model.modelId = [NSString stringWithFormat:@"modelId%d",i];
        [self.modelsArray addObject:model];
    }
    
    if ([NSKeyedArchiver archiveRootObject:self.modelsArray toFile:[[YCTools alloc] getCachePath:@"Appcache"]]) {
        NSLog(@"<<<<< success >>>>");
    }

-(void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
    NSString * path = [[YCTools alloc] getCachePath:@"Appcache"];
    cellArray  = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
    [self.tableView reloadData];
}