ios8 iphone5s,6 touchid指纹登录

+(BOOL)touchIdLogin:(void(^)(int aCode))callBack{
    
    
    if (floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_7_1)
    {
        return NO;
    }
    
    
    // Get the local authentication context:
    LAContext *context = [[LAContext alloc] init];
    
    // Test if fingerprint authentication is available on the device and a fingerprint has been enrolled.
    if ([context canEvaluatePolicy: LAPolicyDeviceOwnerAuthenticationWithBiometrics error:nil])
    {
        NSLog(@"Fingerprint authentication available.");
        //左边按钮
        [context setLocalizedFallbackTitle:@""];
        [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
                localizedReason:@"金手指登录"
                          reply:^(BOOL success, NSError *authenticationError){
								authenticationError.localizedDescription,(int)authenticationError.code,authenticationError.userInfo);

                              
                              //success 0
                              //Aplication retry limit exceeded. -1
                              //Canceled by user. -2
                              //Fallback authentication mechanism selected.-3
                              
                              callBack((int)authenticationError.code);
                              if (success) {
                                  NSLog(@"Fingerprint validated.");
                              }
                              else {
                                  NSLog(@"Fingerprint validation failed: %@", authenticationError.localizedDescription);
                              }
                              
                          }];
        return YES;
    }
    return NO;
}