(绝对有用)iOS获取UUID，并使用keychain存储

UDID被弃用，使用UUID来作为设备的唯一标识。获取到UUID后，如果用NSUserDefaults存储，当程序被卸载后重装时，再获得的UUID和之前就不同了。使用keychain存储可以保证程序卸载重装时，UUID不变。但当刷机或者升级系统后，UUID还是会改变的。但这仍是目前为止最佳的解决办法了，如果有更好的解决办法，欢迎留言。（我整理的解决办法的参考来源：http://blog.k-res.net/archives/1081.html）给大家两个类：

UUID.h中的代码：

#import 尖括号（Foundation/Foundation.h）

@interface UUID : NSObject

+(NSString *)getUUID;

@end

UUID.m中的代码：

#import "UUID.h" #import 尖括号（Foundation/Foundation.h） #import "KeychainItemWrapper.h"

@implementation UUID

+(NSString *)getUUID { KeychainItemWrapper *keychainItem = [[KeychainItemWrapper alloc]

                                initWithIdentifier:@"UUID"
                                   
                                                                             accessGroup:@"YOUR_BUNDLE_SEED.com.yourcompany.userinfo"];


NSString *strUUID = [keychainItem objectForKey:(id)CFBridgingRelease(kSecValueData)];

//首次执行该方法时，uuid为空
if ([strUUID isEqualToString:@""])

{
    CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);

    strUUID = (NSString *)CFBridgingRelease(CFUUIDCreateString (kCFAllocatorDefault,uuidRef));

    [keychainItem setObject:strUUID forKey:(id)CFBridgingRelease(kSecValueData)];

}
return strUUID;

}

@end

第二个类是苹果官方的一个Demo里封装的,Demo的下载地址：http://developer.apple.com/library/ios/#samplecode/GenericKeychain/Listings/Classes_KeychainItemWrapper_h.html#//apple_ref/doc/uid/DTS40007797-Classes_KeychainItemWrapper_h-DontLinkElementID_9

KeychainItemWrapper.h中的代码：

#import 尖括号（UIKit/UIKit.h）

@interface KeychainItemWrapper : NSObject { NSMutableDictionary *keychainItemData; NSMutableDictionary *genericPasswordQuery; }

@property (nonatomic, retain) NSMutableDictionary *keychainItemData; @property (nonatomic, retain) NSMutableDictionary *genericPasswordQuery;

(id)initWithIdentifier: (NSString *)identifier accessGroup:(NSString *) accessGroup;
(void)setObject:(id)inObject forKey:(id)key;
(id)objectForKey:(id)key;
(void)resetKeychainItem;

@end

KeychainItemWrapper.m中的代码：

#import "KeychainItemWrapper.h" #import 尖括号(Security/Security.h)

@interface KeychainItemWrapper (PrivateMethods)

(NSMutableDictionary *)secItemFormatToDictionary:(NSDictionary *)dictionaryToConvert;
(NSMutableDictionary *)dictionaryToSecItemFormat:(NSDictionary *)dictionaryToConvert;
(void)writeToKeychain;

@end

@implementation KeychainItemWrapper

@synthesize keychainItemData, genericPasswordQuery;

(id)initWithIdentifier: (NSString *)identifier accessGroup:(NSString *) accessGroup; { if (self = [super init]) { genericPasswordQuery = [[NSMutableDictionary alloc] init];

[genericPasswordQuery setObject:(id)CFBridgingRelease(kSecClassGenericPassword) forKey:(id)kSecClass]; [genericPasswordQuery setObject:identifier forKey:(id)CFBridgingRelease(kSecAttrGeneric)];

if (accessGroup != nil) { #if TARGET_IPHONE_SIMULATOR

#else [genericPasswordQuery setObject:accessGroup forKey:(id)kSecAttrAccessGroup]; #endif }

    [genericPasswordQuery setObject:(id)CFBridgingRelease(kSecMatchLimitOne) forKey:(id)kSecMatchLimit];
    [genericPasswordQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnAttributes];
    
    NSDictionary *tempQuery = [NSDictionary dictionaryWithDictionary:genericPasswordQuery];
    
    NSMutableDictionary *outDictionary = nil;
    
    if (! SecItemCopyMatching((CFDictionaryRef)tempQuery, (CFTypeRef *)&outDictionary) == noErr)
    {
        
        [self resetKeychainItem];

[keychainItemData setObject:identifier forKey:(id)kSecAttrGeneric]; if (accessGroup != nil) { #if TARGET_IPHONE_SIMULATOR

#else [keychainItemData setObject:accessGroup forKey:(id)kSecAttrAccessGroup]; #endif } } else { self.keychainItemData = [self secItemFormatToDictionary:outDictionary]; }

[outDictionary release]; }

return self; }

(void)dealloc { [keychainItemData release]; [genericPasswordQuery release];

[super dealloc]; }

(void)setObject:(id)inObject forKey:(id)key { if (inObject == nil) return; id currentObject = [keychainItemData objectForKey:key]; if (![currentObject isEqual:inObject]) { [keychainItemData setObject:inObject forKey:key]; [self writeToKeychain]; } }
(id)objectForKey:(id)key { return [keychainItemData objectForKey:key]; }
(void)resetKeychainItem { OSStatus junk = noErr; if (!keychainItemData) { self.keychainItemData = [[NSMutableDictionary alloc] init]; } else if (keychainItemData) { NSMutableDictionary *tempDictionary = [self dictionaryToSecItemFormat:keychainItemData]; junk = SecItemDelete((CFDictionaryRef)tempDictionary); NSAssert( junk == noErr || junk == errSecItemNotFound, @"Problem deleting current dictionary." ); }

[keychainItemData setObject:@"" forKey:(id)kSecAttrAccount]; [keychainItemData setObject:@"" forKey:(id)kSecAttrLabel]; [keychainItemData setObject:@"" forKey:(id)kSecAttrDescription]; [keychainItemData setObject:@"" forKey:(id)kSecValueData]; }
(NSMutableDictionary *)dictionaryToSecItemFormat:(NSDictionary *)dictionaryToConvert { NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionaryToConvert]; [returnDictionary setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass]; NSString *passwordString = [dictionaryToConvert objectForKey:(id)kSecValueData]; [returnDictionary setObject:[passwordString dataUsingEncoding:NSUTF8StringEncoding] forKey:(id)kSecValueData];

return returnDictionary; }
(NSMutableDictionary *)secItemFormatToDictionary:(NSDictionary *)dictionaryToConvert { NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionaryToConvert]; [returnDictionary setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData]; [returnDictionary setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass]; NSData *passwordData = NULL; if (SecItemCopyMatching((CFDictionaryRef)returnDictionary, (CFTypeRef *)&passwordData) == noErr) { [returnDictionary removeObjectForKey:(id)kSecReturnData]; NSString *password = [[[NSString alloc] initWithBytes:[passwordData bytes] length:[passwordData length] encoding:NSUTF8StringEncoding] autorelease]; [returnDictionary setObject:password forKey:(id)kSecValueData]; } else { NSAssert(NO, @"Serious error, no matching item found in the keychain.\n"); }

[passwordData release];

return returnDictionary; }

(void)writeToKeychain { NSDictionary *attributes = NULL; NSMutableDictionary *updateItem = NULL; OSStatus result;

if (SecItemCopyMatching((CFDictionaryRef)genericPasswordQuery, (CFTypeRef *)&attributes) == noErr) { updateItem = [NSMutableDictionary dictionaryWithDictionary:attributes]; [updateItem setObject:[genericPasswordQuery objectForKey:(id)kSecClass] forKey:(id)kSecClass]; NSMutableDictionary *tempCheck = [self dictionaryToSecItemFormat:keychainItemData]; [tempCheck removeObjectForKey:(id)kSecClass];

#if TARGET_IPHONE_SIMULATOR

[tempCheck removeObjectForKey:(id)kSecAttrAccessGroup]; #endif result = SecItemUpdate((CFDictionaryRef)updateItem, (CFDictionaryRef)tempCheck); NSAssert( result == noErr, @"Couldn't update the Keychain Item." ); } else { result = SecItemAdd((CFDictionaryRef)[self dictionaryToSecItemFormat:keychainItemData], NULL); NSAssert( result == noErr, @"Couldn't add the Keychain Item." ); } }

@end

PS: 1. KeychainItemWrapper类在官方Demo里面也有，如果我复制出错了，大家可以在上面的链接上下载官方Demo. 2.使用时要添加Security.framework 3. 尤为注意的是，UUID类下面这句代码中group的设置方法。 KeychainItemWrapper *keychainItem = [[KeychainItemWrapper alloc]

                                     initWithIdentifier:@"UUID"
                                   
                                     accessGroup:@"YOUR_BUNDLE_SEED.com.yourcompany.userinfo"];
（1）在项目相同的目录下创建KeychainAccessGroups.plist文件。
     (绝对有用)iOS获取UUID，并使用keychain存储

该文件的结构中最顶层的节点必须是一个名为“keychain-access-groups”的Array，并且该Array中每一项都是一个描述分组的NSString。YOUR_BUNDLE_SEED.com.yourcompany.userinfo就是要设置的组名。（2）在项目相同的目录下创建KeychainAccessGroups.plist文件。在Target-Build Settings-Code Signing栏下的Code Signing Entitlements右侧添加KeychainAccessGroups.plist，如下图。 (绝对有用)iOS获取UUID，并使用keychain存储

到此，工作就完成了。首次安装程序时，打印出一个uuid,当把程序卸载后，再用getUUID获得 uuid，打印出来的结果和之前相同。证明达到目的。