这篇攻略是利用keychain来持久化存储数据，所以可以利用这个来做设备唯一标志符。另外你只要按照我的步骤操作就没有什么问题，简称傻瓜式操作~~
1.先来了解一下keychain
这里我想很多人都对yourAppID理解不对，这个yourAppID不是工程的appid，而是在开发者中心的个人界面就有；其次yourAppID只对应所使用的开发者账号。
2.对这个东西有所理解后，开始动手操作了。
把这两个类文件添加到你项目里，按照我的文件命名即可。
第一个 ：
#import@interface KeychainItemWrapper : NSObject
{
NSMutableDictionary *keychainItemData; // The actual keychain item data backing store.
NSMutableDictionary *genericPasswordQuery; // A placeholder for the generic keychain item query used to locate the item.
}
@property (nonatomic, retain) NSMutableDictionary *keychainItemData;
@property (nonatomic, retain) NSMutableDictionary *genericPasswordQuery;
// Designated initializer.
- (id)initWithAccount:(NSString *)account service:(NSString *)service accessGroup:(NSString *) accessGroup;
- (id)initWithIdentifier: (NSString *)identifier accessGroup:(NSString *) accessGroup;
- (void)setObject:(id)inObject forKey:(id)key;
- (id)objectForKey:(id)key;
// Initializes and resets the default generic keychain item data.
- (void)resetKeychainItem;
@end
#import "KeychainItemWrapper.h"#import/*
These are the default constants and their respective types,
available for the kSecClassGenericPassword Keychain Item class:
kSecAttrAccessGroup - CFStringRef
kSecAttrCreationDate - CFDateRef
kSecAttrModificationDate - CFDateRef
kSecAttrDescription - CFStringRef
kSecAttrComment - CFStringRef
kSecAttrCreator - CFNumberRef
kSecAttrType - CFNumberRef
kSecAttrLabel - CFStringRef
kSecAttrIsInvisible - CFBooleanRef
kSecAttrIsNegative - CFBooleanRef
kSecAttrAccount - CFStringRef
kSecAttrService - CFStringRef
kSecAttrGeneric - CFDataRef
See the header file Security/SecItem.h for more details.
*/
@interface KeychainItemWrapper (PrivateMethods)
/*
The decision behind the following two methods (secItemFormatToDictionary and dictionaryToSecItemFormat) was
to encapsulate the transition between what the detail view controller was expecting (NSString *) and what the
Keychain API expects as a validly constructed container class.
*/
- (NSMutableDictionary *)secItemFormatToDictionary:(NSDictionary *)dictionaryToConvert;
- (NSMutableDictionary *)dictionaryToSecItemFormat:(NSDictionary *)dictionaryToConvert;
// Updates the item in the keychain, or adds it if it doesn't exist.
- (void)writeToKeychain;
@end
@implementation KeychainItemWrapper
@synthesize keychainItemData, genericPasswordQuery;
- (id)initWithAccount:(NSString *)account service:(NSString *)service accessGroup:(NSString *) accessGroup;
{
if (self = [super init])
{
NSAssert(account != nil || service != nil, @"Both account and service are nil. Must specifiy at least one.");
// Begin Keychain search setup. The genericPasswordQuery the attributes kSecAttrAccount and
// kSecAttrService are used as unique identifiers differentiating keychain items from one another
genericPasswordQuery = [[NSMutableDictionary alloc] init];
[genericPasswordQuery setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
[genericPasswordQuery setObject:account forKey:(id)kSecAttrAccount];
[genericPasswordQuery setObject:service forKey:(id)kSecAttrService];
// The keychain access group attribute determines if this item can be shared
// amongst multiple apps whose code signing entitlements contain the same keychain access group.
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[genericPasswordQuery setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
}
// Use the proper search constants, return only the attributes of the first match.
[genericPasswordQuery setObject:(id)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)
{
// Stick these default values into keychain item if nothing found.
[self resetKeychainItem];
//Adding the account and service identifiers to the keychain
[keychainItemData setObject:account forKey:(id)kSecAttrAccount];
[keychainItemData setObject:service forKey:(id)kSecAttrService];
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[keychainItemData setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
}
}
else
{
// load the saved data from Keychain.
self.keychainItemData = [self secItemFormatToDictionary:outDictionary];
}
[outDictionary release];
}
return self;
}
- (id)initWithIdentifier: (NSString *)identifier accessGroup:(NSString *) accessGroup;
{
if (self = [super init])
{
// Begin Keychain search setup. The genericPasswordQuery leverages the special user
// defined attribute kSecAttrGeneric to distinguish itself between other generic Keychain
// items which may be included by the same application.
genericPasswordQuery = [[NSMutableDictionary alloc] init];
[genericPasswordQuery setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
[genericPasswordQuery setObject:identifier forKey:(id)kSecAttrAccount];
// The keychain access group attribute determines if this item can be shared
// amongst multiple apps whose code signing entitlements contain the same keychain access group.
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[genericPasswordQuery setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
}
// Use the proper search constants, return only the attributes of the first match.
[genericPasswordQuery setObject:(id)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)
{
// Stick these default values into keychain item if nothing found.
[self resetKeychainItem];
// Add the generic attribute and the keychain access group.
[keychainItemData setObject:identifier forKey:(id)kSecAttrAccount];
if (accessGroup != nil)
{
#if TARGET_IPHONE_SIMULATOR
// Ignore the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
#else
[keychainItemData setObject:accessGroup forKey:(id)kSecAttrAccessGroup];
#endif
}
}
else
{
// load the saved data from Keychain.
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." );
}
// Default attributes for keychain item.
[keychainItemData setObject:@"" forKey:(id)kSecAttrAccount];
[keychainItemData setObject:@"" forKey:(id)kSecAttrLabel];
[keychainItemData setObject:@"" forKey:(id)kSecAttrDescription];
// Default data for keychain item.
[keychainItemData setObject:@"" forKey:(id)kSecValueData];
}
- (NSMutableDictionary *)dictionaryToSecItemFormat:(NSDictionary *)dictionaryToConvert
{
// The assumption is that this method will be called with a properly populated dictionary
// containing all the right key/value pairs for a SecItem.
// Create a dictionary to return populated with the attributes and data.
NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionaryToConvert];
// Add the Generic Password keychain item class attribute.
[returnDictionary setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
// Convert the NSString to NSData to meet the requirements for the value type kSecValueData.
// This is where to store sensitive data that should be encrypted.
NSString *passwordString = [dictionaryToConvert objectForKey:(id)kSecValueData];
[returnDictionary setObject:[passwordString dataUsingEncoding:NSUTF8StringEncoding] forKey:(id)kSecValueData];
return returnDictionary;
}
- (NSMutableDictionary *)secItemFormatToDictionary:(NSDictionary *)dictionaryToConvert
{
// The assumption is that this method will be called with a properly populated dictionary
// containing all the right key/value pairs for the UI element.
// Create a dictionary to return populated with the attributes and data.
NSMutableDictionary *returnDictionary = [NSMutableDictionary dictionaryWithDictionary:dictionaryToConvert];
// Add the proper search key and class attribute.
[returnDictionary setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
[returnDictionary setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
// Acquire the password data from the attributes.
NSData *passwordData = NULL;
if (SecItemCopyMatching((CFDictionaryRef)returnDictionary, (CFTypeRef *)&passwordData) == noErr)
{
// Remove the search, class, and identifier key/value, we don't need them anymore.
[returnDictionary removeObjectForKey:(id)kSecReturnData];
// Add the password to the dictionary, converting from NSData to NSString.
NSString *password = [[[NSString alloc] initWithBytes:[passwordData bytes] length:[passwordData length]
encoding:NSUTF8StringEncoding] autorelease];
[returnDictionary setObject:password forKey:(id)kSecValueData];
}
else
{
// Don't do anything if nothing is found.
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)
{
// First we need the attributes from the Keychain.
updateItem = [NSMutableDictionary dictionaryWithDictionary:attributes];
// Second we need to add the appropriate search key/values.
[updateItem setObject:[genericPasswordQuery objectForKey:(id)kSecClass] forKey:(id)kSecClass];
// Lastly, we need to set up the updated attribute list being careful to remove the class.
NSMutableDictionary *tempCheck = [self dictionaryToSecItemFormat:keychainItemData];
[tempCheck removeObjectForKey:(id)kSecClass];
#if TARGET_IPHONE_SIMULATOR
// Remove the access group if running on the iPhone simulator.
//
// Apps that are built for the simulator aren't signed, so there's no keychain access group
// for the simulator to check. This means that all apps can see all keychain items when run
// on the simulator.
//
// If a SecItem contains an access group attribute, SecItemAdd and SecItemUpdate on the
// simulator will return -25243 (errSecNoAccessForItem).
//
// The access group attribute will be included in items returned by SecItemCopyMatching,
// which is why we need to remove it before updating the item.
[tempCheck removeObjectForKey:(id)kSecAttrAccessGroup];
#endif
// An implicit assumption is that you can only update a single item at a time.
result = SecItemUpdate((CFDictionaryRef)updateItem, (CFDictionaryRef)tempCheck);
NSAssert( result == noErr, @"Couldn't update the Keychain Item." );
}
else
{
// No previous item found; add the new one.
result = SecItemAdd((CFDictionaryRef)[self dictionaryToSecItemFormat:keychainItemData], NULL);
NSAssert( result == noErr, @"Couldn't add the Keychain Item." );
}
}
@end
```
第二个：
```
#import@interface AppUntils : NSObject
+(void)saveUUIDToKeyChain;
+(NSString *)readUUIDFromKeyChain;
+ (NSString *)getUUIDString;
@end
#import "AppUntils.h"#import#import "KeychainItemWrapper.h"
@implementation AppUntils
#pragma mark - 保存和读取UUID
+(void)saveUUIDToKeyChain{
KeychainItemWrapper *keychainItem = [[KeychainItemWrapper alloc] initWithAccount:@"Identfier" service:@"AppName" accessGroup:nil];
NSString *string = [keychainItem objectForKey: (__bridge id)kSecAttrGeneric];
if([string isEqualToString:@""] || !string){
[keychainItem setObject:[self getUUIDString] forKey:(__bridge id)kSecAttrGeneric];
}
}
+(NSString *)readUUIDFromKeyChain{
KeychainItemWrapper *keychainItemm = [[KeychainItemWrapper alloc] initWithAccount:@"Identfier" service:@"AppName" accessGroup:nil];
NSString *UUID = [keychainItemm objectForKey: (__bridge id)kSecAttrGeneric];
return UUID;
}
+ (NSString *)getUUIDString
{
CFUUIDRef uuidRef = CFUUIDCreate(kCFAllocatorDefault);
CFStringRef strRef = CFUUIDCreateString(kCFAllocatorDefault , uuidRef);
NSString *uuidString = [(__bridge NSString*)strRef stringByReplacingOccurrencesOfString:@"-" withString:@""];
CFRelease(strRef);
CFRelease(uuidRef);
return uuidString;
}
@end
3.因为KeychainItemWrapper.m文件是在非ARC环境下运行的，所以需要设置非arc编译环境，在tag下设置，如图所示：
4.在项目相同的目录下创建KeychainAccessGroups.plist文件，不是在info.plist里。
按照图里要求填写，前缀是appid，我自己瞎写的一个，你需要用对应你的开发者账号的来弄，还有公司名。
5.大功告成咯~~我们就随便用用看吧~~
添加两个头文件，这个方法就能获取到UUID
要取出来，用 readUUIDFromKeyChain 即可。
最后
有时候我们会发现有些app比较赖皮，卸载后再装竟然不需要登录就能上去，这个大多数原因也是因为他们把用户数据保存在了 keychain 里；另外如果涉及到安全性较高的，即使有两款产品，我们也不会建议让他们使用同一个 keychain。当然，如果只是采集一些用户行为数据的话，这个还是可以的
参考文章的链接 ：
