ios学习记录 day36 UI12初级数据持久化(沙盒)

浏览数：28 / 时间：2015年06月11日

1.沙盒机制

文件夹之间不能通信

Finder前往按Alt键出来资源库

//返回类型是个数组第一个参数是枚举,有很多文件夹类型第三个参数YES的话是详细路径,NO的话~/最后一个文件夹名
//数组里放的是同一文件下所有相同名字的文件夹按角标取出我们要的

NSArray *arr = NSSearchPathForDirectoriesInDomains(<#NSSearchPathDirectory directory#>, <#NSSearchPathDomainMask domainMask#>, <#BOOL expandTilde#>)

//返回bundle(.app)文件夹路径

-(NSString *)searchInBundle
{
NSString *bundlePath = [[NSBundle mainBundle]pathForResource:@"InfoPlist" ofType:@"strings"];
return bundlePath;
}
Bundle 程序运行时不可改安装程序是只有这里有东西用的时候把Bundle的东西拷贝到下面三个文件夹里用

Documents文件夹存数据库 / coreData文件限制不能超过20M

Library文件夹 caches存储图片网址... Preferences存储系统的配置文件NSUserDefaulfs

tmp文件夹存储临时文件老版本按home键自动清空现在需要手动和上两个一样

2.简单对象的读写文件(NSString,Array,dic,set)

atomically 是否自动存储 encoding 编码格式(国际编码汉字一般用的 NSUTF8StringEncoding) error:存储错误信息双指针类型

#pragma mark 字符串的写入
-(void)writeWithString
{
    NSString *str = [self searchPath];
    //添加字符
//    NSString *newPath = [str stringByAppendingString:@"/text.txt"];
    //拼接字符
    NSString *newPath = [NSString stringWithFormat:@"%@/%@",str,@"text.txt"];
//    NSLog(@"newPath == %@",newPath);
    NSString *writeStr = @"xiaozhangdezifuchuan";

    NSError *error = nil;

    [writeStr writeToFile:newPath atomically:YES encoding:NSUTF8StringEncoding error:&error];//第四个参数直接写nil也可以
    if (error) {
        NSLog(@"error == %@",error);
    }
}

#pragma mark 字符串的读取
-(void)readWithString
{
    NSString *path = [self searchPath];
    NSString *newPath = [path stringByAppendingString:@"/text.txt"];

    NSError *error = nil;
    NSString *readStr = [NSString stringWithContentsOfFile:newPath encoding:NSUTF8StringEncoding error:&error];//+方法
    if (error) {
        NSLog(@"error ===== %@",error);
    }
    NSLog(@"read == %@",readStr);

    NSString *a = [[NSString alloc]initWithContentsOfFile:newPath encoding:NSUTF8StringEncoding error:&error];//-方法
    NSLog(@"a === %@",a);

}

//写入

1.创建要写入的内容

2.找路径加新路径

3.写入方法writeToFile

4.调用

//读取

1.找路径加名

2.读取方法ContentsOfFile

3.调用

//UIImage 转换成data类型

UIImage *image = [UIImage imageNamed:@"刘健.jpg"] ;
NSData *data = UIImagePNGRepresentation(image);

NSString *name = @"shengqingjun";
//字符串转换成2进制
NSData *data = [name dataUsingEncoding:NSUTF8StringEncoding];

//2进制转换成字符串只有一个方法
NSString *str = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

3.复杂对象的读写文件(自定义model,有属性/在Foundation框架内不存在,无法通过writeToFile写入,至少有一个实例对象)

NSCoding协议

ABPersonInfo.m//自定义的类型

//归档的方法
- (void)encodeWithCoder:(NSCoder *)aCoder
{
    [aCoder encodeObject:self.name forKey:@"name"];
    [aCoder encodeObject:self.age forKey:@"age"];
    [aCoder encodeObject:self.frame forKey:@"frame"];
}
//解档的方法
- (id)initWithCoder:(NSCoder *)aDecoder
{
    if (self = [super init]) {
        self.name = [aDecoder decodeObjectForKey:@"name"];
        self.age = [aDecoder decodeObjectForKey:@"age"];
        self.frame = [aDecoder decodeObjectForKey:@"frame"];
    }
    return self;
}

FirstViewController.m

//归档对象
-(void)archiveObject
{
    ABPersonInfo *person = [[ABPersonInfo alloc]init];
    person.name = @"sqj";
    person.age = [NSNumber numberWithInt:12];
    person.frame = [NSValue valueWithCGPoint:CGPointMake(10, 20)];

    NSData *data = [NSKeyedArchiver archivedDataWithRootObject:person];

    NSString *path = [self searchPath];
    NSString *newPath = [path stringByAppendingString:@"/person.txt"];
    [data writeToFile:newPath atomically:YES];
}
//解档对象
-(void)unArchivedObject
{
    NSString *path = [self searchPath];
    NSString *newPath = [path stringByAppendingString:@"/person.txt"];
    NSData *data = [NSData dataWithContentsOfFile:newPath];
    //解档
    ABPersonInfo *person = [NSKeyedUnarchiver unarchiveObjectWithData:data];
    NSLog(@"name == %@,age == %@,frame == %@",person.name,person.age,person.frame);
}

4.NSUserDefaults 系统的一个简单的本地存储 plist文件存的东西比较小

#pragma mark -
#pragma mark NSUserDefaults 存储小型数据
//存储
-(void)writeUserDefaults
{
    NSUserDefaults *object = [NSUserDefaults standardUserDefaults];
    //[object setObject:@"shenqingjun" forKey:@"name"];//第一个参数系统的对象
    //添加内容
    [object setObject:@"aishangyipiyema" forKey:@"xinqing"];
    //同步存储
    [object synchronize];
}
//读取
-(void)readUserDefaules{
    NSUserDefaults *object = [NSUserDefaults standardUserDefaults];
    NSString *name = [object objectForKey:@"name"];
    NSLog(@"name == %@",name);
}