获取设备UUID，并使用keychain存储

      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。

1.新建一个工程，看一下自己的Bundle Id.这个Bundle Id 要和你用真机测试时的证书上面的Bundle Id相匹配。

2.Target - Capabilities - Keychain Sharing  改为ON

然后，在左侧的目录会自动生成Entitlements文件，不用自己创建了。

注意：Bundle Identifier、Keychain Sharing的Keychain Groups、Entitlements文件的Keychain Access Groups的第一个元素，它们要保持上图所示的一致性。

设置好了以后可以运行下程序，没问题可以进行下一步。

3.接下来，就是UUID类和keychain类了（我也是从网上搬运来的，作者看到勿喷。。。）

UUID.h

#import  

@interface UUID : NSObject

+(NSString *)getUUID;

@end

UUID.m

#import "UUID.h"

#import "KeyChainStore.h"

@implementation UUID

+(NSString *)getUUID

{

NSString * strUUID = (NSString *)[KeyChainStore load:@"com.company.app.usernamepassword"];

//首次执行该方法时，uuid为空

if ([strUUID isEqualToString:@""] || !strUUID)

{

//生成一个uuid的方法

CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);

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

//将该uuid保存到keychain

[KeyChainStore save:KEY_USERNAME_PASSWORD data:strUUID];

}

return strUUID;

}

@end

KeyChainStore.h

#import

@interface KeyChainStore : NSObject

+ (void)save:(NSString *)service data:(id)data;

+ (id)load:(NSString *)service;

+ (void)deleteKeyData:(NSString *)service;

@end

KeyChainStore.m

#import "KeyChainStore.h"

@implementation KeyChainStore

+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {

return [NSMutableDictionary dictionaryWithObjectsAndKeys:

(id)kSecClassGenericPassword,(id)kSecClass,

service, (id)kSecAttrService,

service, (id)kSecAttrAccount,

(id)kSecAttrAccessibleAfterFirstUnlock,(id)kSecAttrAccessible,

nil];

}

+ (void)save:(NSString *)service data:(id)data {

//Get search dictionary

NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];

//Delete old item before add new item

SecItemDelete((CFDictionaryRef)keychainQuery);

//Add new object to search dictionary(Attention:the data format)

[keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(id)kSecValueData];

//Add item to keychain with the search dictionary

SecItemAdd((CFDictionaryRef)keychainQuery, NULL);

}

+ (id)load:(NSString *)service {

id ret = nil;

NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];

//Configure the search setting

//Since in our simple case we are expecting only a single attribute to be returned (the password) we can set the attribute kSecReturnData to kCFBooleanTrue

[keychainQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];

[keychainQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];

CFDataRef keyData = NULL;

if (SecItemCopyMatching((CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {

@try {

ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge NSData *)keyData];

} @catch (NSException *e) {

NSLog(@"Unarchive of %@ failed: %@", service, e);

} @finally {

}

}

if (keyData)

CFRelease(keyData);

return ret;

}

+ (void)deleteKeyData:(NSString *)service {

NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];

SecItemDelete((CFDictionaryRef)keychainQuery);

}

@end

将这两个类添加到工程中

4.新建一个pch文件，给pch文件添加的内容如下：

#define  KEY_USERNAME_PASSWORD @"com.company.app.usernamepassword"

#define  KEY_USERNAME @"com.company.app.username"

#define  KEY_PASSWORD @"com.company.app.password"

添加pch文件方法可参照：创建.pch文件 -

5.最后，在viewController里面添加头文件，调用

NSString * uuid= [UUID getUUID];

NSLog(@"UUID = %@",uuid);

打印出来的是这个样子：UUID = F6574AFA-6B6E-4699-A889-799944AA3861

然后呢就可以多试几次，看看各种情况下，会不会改变

PS：重装系统没有试过，但是卸载APP重装后，UUID不会变，要是有人测试过重装系统后，一定将结果告诉我喔！