/**
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
2.1 归档
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);
使用数据对象自带的方法，如字典类写文件：
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
NSString *error;
NSData *xmlData = [NSPropertyListSerialization dataFromPropertyList:dataDictionary format:NSPropertyListXMLFormat_v1_0 errorDescription:&error];
if(xmlData) {
NSLog(@"No error creating XML data.");
[xmlData writeToFile:@"/Users/zhoumoban/Desktop/test2.plist" atomically:YES];
} else {
if (error) {
NSLog(@"error:%@", error);
// [error release];
}
}
//读取
NSDictionary *dictionaryFromFile2 = (NSDictionary *)[NSPropertyListSerialization propertyListWithData:[NSData dataWithContentsOfFile:@"/Users/zhoumoban/Desktop/test2.plist"] options:0 format:NULL error:&error];
NSLog(@"＝＝＝%@",[dictionaryFromFile2 objectForKey:@"intNumber"]);