标签:des style blog http io ar os 使用 sp
/** 1:Documents:应用中用户数据可以放在这里,iTunes备份和恢复的时候会包括此目录 2:tmp:存放临时文件,iTunes不会备份和恢复此目录,此目录下文件可能会在应用退出后删除 3:Library/Caches:存放缓存文件,iTunes不会备份此目录,此目录下文件不会在应用退出删除 */ NSArray *paths1=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask , YES); NSString *documentsDirect=[paths1 objectAtIndex:0]; assert(1 == paths1.count); NSLog(@">>documentsDirect=%@",documentsDirect); NSArray *Librarypaths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSDocumentDirectory, YES); NSString* libraryDirectory = [Librarypaths objectAtIndex:0]; NSLog(@">>Librarypaths.length =%d",[Librarypaths count]); assert(1 < Librarypaths.count); NSLog(@"libraryDirectory=%@",libraryDirectory); //如果要指定其他文件目录,比如Caches目录,需要更换目录工厂常量,上面代码其他的可不变 NSArray *pathcaches=NSSearchPathForDirectoriesInDomains(NSCachesDirectory , NSUserDomainMask , YES); NSString* cacheDirectory = [pathcaches objectAtIndex:0]; NSLog(@"cacheDirectory=%@",cacheDirectory); /** 使用NSSearchPathForDirectoriesInDomains只能定位Caches目录和Documents目录。 tmp目录,不能按照上面的做法获得目录了,有个函数可以获得应用的根目录 */ NSString *tempDir1=NSHomeDirectory() ; NSString *tempDir2=NSTemporaryDirectory(); NSLog(@"tempDir1=%@",tempDir1); NSLog(@"tempDir2=%@",tempDir2);
归档 普通自定义对象和字节流之间的转换
序列化 某些特定类型(NSDictionary, NSArray, NSString, NSDate, NSNumber,NSData)的数据和字节流之间(通常将其保存为plist文件)的转换
如果我们需要将自定义的一个对象保存到文件,应该如何做呢?
这里引入两个东西:一个是NSCoding协议 ;另一个是NSKeyedArchiver,NSKeyedArchiver其实继承于NSCoder,可以以键值对的方式将对象的属性进行序列化和反序列化。
具体的过程可以这样描述 通过NSKeyedArchiver 可以将实现了NSCoding协议的对象 和 字节流 相互转换 。
像一些框架中的数据类型如NSDictionary,NSArray,NSString... 都已经实现了NSCoding协议,所以可以直接对他们进行归档操作。
这里来一个比较完整的例子,一个Address类,一个User类,User类下有个Address类型的属性
#import <Foundation/Foundation.h> @interface Address : NSObject<NSCoding> { NSString *country; NSString *city; } @property(nonatomic,copy) NSString *country; @property(nonatomic,copy) NSString *city; @end
#import "Address.h" @implementation Address @synthesize country; @synthesize city; - (void)encodeWithCoder:(NSCoder *)aCoder{ [aCoder encodeObject:country forKey:@"country"]; [aCoder encodeObject:city forKey:@"city"]; } - (id)initWithCoder:(NSCoder *)aDecoder{ if (self = [super init]) { [self setCountry:[aDecoder decodeObjectForKey:@"country"]]; [self setCity:[aDecoder decodeObjectForKey:@"city"]]; } return self; } @end
#import <Foundation/Foundation.h> #import "Address.h" @interface User : NSObject<NSCoding>{ NSString *_name; NSString *_password; Address *_address; } @property(nonatomic,copy) NSString *name; @property(nonatomic,copy) NSString *password; @property(nonatomic,retain) Address *address; @end
#import "User.h" @implementation User @synthesize name = _name; @synthesize password = _password; @synthesize address = _address; - (void)encodeWithCoder:(NSCoder *)aCoder{ [aCoder encodeObject:_name forKey:@"name"]; [aCoder encodeObject:_password forKey:@"password"]; [aCoder encodeObject:_address forKey:@"address"]; } - (id)initWithCoder:(NSCoder *)aDecoder{ if (self = [super init]) { [self setName:[aDecoder decodeObjectForKey:@"name"]]; [self setPassword:[aDecoder decodeObjectForKey:@"password"]]; [self setAddress:[aDecoder decodeObjectForKey:@"address"]]; } return self; } @end
操作应用
NSString *tempDir2=NSTemporaryDirectory(); // Do any additional setup after loading the view, typically from a nib. Address *myAddress = [[Address alloc] init] ; myAddress.country = @"中国"; myAddress.city = @"杭州"; User *user = [[User alloc] init] ; user.name = @"卢克"; user.password = @"lukejin"; user.address = myAddress; //归档 保存的是plist的二进制数据格式 NSString *path = [tempDir2 stringByAppendingPathComponent:@"user"]; [NSKeyedArchiver archiveRootObject:user toFile:path]; //从文档中读取 User *object = [NSKeyedUnarchiver unarchiveObjectWithFile:path]; NSLog(@"object.name : %@",object.name);
数据:
NSMutableDictionary *dataDictionary = [[NSMutableDictionary alloc] init] ; [dataDictionary setValue:[NSNumber numberWithInt:222] forKey:@"intNumber"]; [dataDictionary setValue:[NSArray arrayWithObjects:@"1",@"2", nil] forKey:@"testArray"];
写文件
[dataDictionary writeToFile:@"/Users/zhoumoban/Desktop/test.plist" atomically:YES];
读文件:
NSDictionary *dictionaryFromFile = [NSDictionary dictionaryWithContentsOfFile:@"/Users/zhoumoban/Desktop/test.plist"]; NSLog(@"%@",[dictionaryFromFile objectForKey:@"intNumber"]);
另外:使用NSPropertyListSerialization类。通过NSPropertyListSerialization类可以将数据对象直接转成NSData或者直接写到文件或者流中去
iOS 各种系统文件目录 临时,缓存,document,lib,归档,序列化
标签:des style blog http io ar os 使用 sp
原文地址:http://www.cnblogs.com/lovewx/p/4158999.html