IssueTracker

Hi Ed, Thank you so much for these suggestions. I've been reviewing them and merging them in. Hopefully it should be live. I've included a thank you note too in the article.

But I do not have issue if I remove "setDeviceCredentialAllowed", that's what make me thing there is something wrong

Steps to reproduce:
- Fingerprint configured in settings
- Biometric prompt showing
- Tap on cancel
- Tap on Toast button
- Toast is showing

Scenario 2:
- Device credential configured (Pattern)
- Biometric prompt showing pattern authentication
- Tap on Cancel
- Tap on Toast button
- Activity is not responding (can't tap on button)

Behaviour is not the same between biometric and credentials authentication

Assigning back to triage queue so it's not lost in mine, will take a look soon.

mathieumolette@gmail.com: You're right that this is likely caused by invoking BiometricPrompt in onResume, causing an authentication loop. But the specific side effect of having the transparent handling activity get stuck onscreen is definitely not intended and ideally shouldn't be this easy to run into. I'll look into making this more robust.

Project: platform/frameworks/support
Branch: androidx-master-dev

commit a9cbd7e42fd38c18395c23fd17622c731c60c724
Author: Curtis Belmonte <curtislb@google.com>
Date:   Mon Oct 28 11:00:33 2019

    Fix leak of biometric credential handler activity
   
    Due to a race condition, which can be triggered by launching
    BiometricPrompt immediately after it's dismissed (e.g., by calling
    authenticate() in onResume() or onCreate()), it's currently possible for
    the transparent DeviceCredentialHandlerActivity to get stuck onscreen.
    This results in no visible change but consumes all touch events until
    the user presses back or pauses the activity.
   
    This commit fixes the issue of the activity getting stuck onscreen by
    ensuring that DeviceCredentialHandlerActivity is finished (without an
    explicit authentication result) in this case.
   
    Test: Have sample app call BiometricPrompt#authenticate() in onResume()
    Before: After first auth, transparent activity is stuck onscreen
    After: After first auth, the prompt launches again successfully
   
    Fixes: 143091227
    Change-Id: Id11918662be4634c017094806816a990e84ffd62

M       biometric/src/main/java/androidx/biometric/DeviceCredentialHandlerActivity.java

https://android-review.googlesource.com/1151594
https://goto.google.com/android-sha1/a9cbd7e42fd38c18395c23fd17622c731c60c724

  The following changes were cherrypicked through Coastguard (https://android-build.googleplex.com/coastguard/)
  Release Track: (https://android-build.googleplex.com/coastguard/dashboard/5176090922385408/#/history/all)
  Created: 2019-11-26 18:05:22.006209+00:00
  Changes: aosp/1151594