本文转载至 http://blog.csdn.net/jinkaiouyang/article/details/35555123

IOS8将指纹识别技术开放出来了。我们能够利用用户设置的touch ID来进行用户鉴权。

TouchID的API主要集成在LocalAuthentication.framework中。将改framework加入到工程中，并且需要iPhone5S和IOS8系统的支持，就能使用TouchID的API

了。

TouchID的API非常简单：

1、使用之前，需要先判断TouchID是否支持

 

- (BOOL)canEvaluatePolicy:(LAPolicy)policy error:(NSError * __autoreleasing *)error;

2、调用TouchID识别接口

 

 

- (void)evaluatePolicy:(LAPolicy)policy localizedReason:(NSString *)localizedReason reply:(void(^)(BOOL success, NSError *error))reply;

 

 

policy枚举，表示需要使用到的权限，目前只有一个Biometrics，意思指的就是TouchID

 

{
    /// Device owner was authenticated using a biometric method. Biometrics (Touch ID) is required.
    /// If Touch ID is not enabled, policy evaluation fails.
    LAPolicyDeviceOwnerAuthenticationWithBiometrics = kLAPolicyDeviceOwnerAuthenticationWithBiometrics
} NS_ENUM_AVAILABLE(10_10, 8_0);

 

 

localizedReason

使用TouchID的理由，会出现在弹框中，提示用户。这个字段必须填写且不为nil或空值，否则会抛NSInvalidArgumentException异常，

 

 

(void(^)(BOOL success,NSError *error))

TouchID输入的结果回调。使用block方式。

 

示例代码：

 

LAContext *context = [[LAContext alloc] init];
NSError *contextError = nil;
NSString *localizedReasonString = @"Need Authorize";

if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&contextError]) {
    [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
            localizedReason:localizedReasonString
                      reply:^(BOOL success, NSError *error) {
                          NSString *title, *message;

                          if (success) {
                              title = @"Authorize Success";
                              message = nil;
                          } else {
                              title = @"Authorize Faied";
                              message = error.localizedFailureReason;
                          }

                          UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title
                                                                              message:message
                                                                             delegate:nil
                                                                    cancelButtonTitle:@"OK"
                                                                    otherButtonTitles:nil];
                          [alertView show];
                      }];
} else {
    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Context Error"
                                                        message:contextError.localizedFailureReason
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
    [alertView show];