authentication - TouchID 转发到系统密码认证

Question

我想使用 TouchID 验证我自己的应用程序。

1.我希望用户可以点击“输入密码”来调用系统内置密码屏幕进行身份验证，如果成功则进入我自己的应用程序。
但我不知道如何在“case LAErrorUserFallback”中将其转发到密码验证 View ，如下面的屏幕所示


这是我的代码:

LAContext *context = [[LAContext alloc] init];
__block  NSString *msg;
__block  BOOL bAuth;
// show the authentication UI with our reason string
[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:NSLocalizedString(@"Unlock APP With FingerPrint", nil) reply:
^(BOOL success, NSError *authenticationError) {

   if (success) {
      bAuth = YES;
      msg =[NSString stringWithFormat:NSLocalizedString(@"EVALUATE_POLICY_SUCCESS", nil)];
      dispatch_async(dispatch_get_main_queue(), ^{
         [[MYAppDelegate theDelegate] initializeAppAfterKeyVaultUnlocked];
      });
      NSLog(@"%@",msg);
   } else {
      bAuth = NO;
      switch (authenticationError.code) {
         case LAErrorAuthenticationFailed:
            msg = [NSString stringWithFormat:NSLocalizedString(@"Authentication Failed", nil)];
            // ...
            break;

         case LAErrorUserCancel:
            msg = [NSString stringWithFormat:NSLocalizedString(@"User pressed Cancel button", nil)];
            dispatch_async(dispatch_get_main_queue(), ^{
               [[MYAppDelegate theDelegate] exitAndLock];
            });

            break;

         case LAErrorUserFallback:
            msg = [NSString stringWithFormat:NSLocalizedString(@"User pressed \"Enter Password\"", nil)];
            //Here I want to fallback to iOS build-in passcode authenticate view, and get the auth result.
            break;

         default:
            msg = [NSString stringWithFormat:NSLocalizedString(@"Touch ID is not configured", nil)];
            // ...
            break;
      }
      NSLog(@"%@",authenticationError.localizedDescription);

   }


}];

Answer 1

现在在 iOS 9 中它实际上非常简单——你只需要使用 LAPolicyDeviceOwnerAuthentication而不是 LAPolicyDeviceOwnerAuthenticationWithBiometrics
所以在你的代码中你只需替换这个:

[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:NSLocalizedString(@"Unlock APP With FingerPrint", nil) reply:
^(BOOL success, NSError *authenticationError) {

有了这个:

[context evaluatePolicy:LAPolicyDeviceOwnerAuthentication localizedReason:NSLocalizedString(@"Unlock APP With FingerPrint", nil) reply:
^(BOOL success, NSError *authenticationError) {

因此，当用户无法通过指纹进行身份验证时，会出现“输入密码”选项，该选项将调用系统密码输入屏幕。