Tukukkk

My app is starting an activity from another package with startActivityForResult. I observed problems when my launching activity gets recreated and saw that onActivityResult is not called in that case after the started activity returns. (It is called correctly if I do not trigger activity recreation.)

These are the steps I performed:

• Start my activity


• Click my button which calls startActivityForResult on the ykDroid app


• Bring my app to background. This causes my activity to be destroyed as I have enabled this in the Android developer settings


• Bring my app back to foreground (I see OnCreate is called)


• Swipe a Yubikey NEO which causes the other activity to return.


• Watch logcat to see that OnActivityResult is not called.

I found out that if I call RequestPermissions for Permission.UseFingerprint I get the OnActivityResult callback even after activity recreation. I don't have a clue why. Can anybody explain this behavior?
Could it be related to ykDroid? see https://github.com/pp3345/ykDroid for their source code.

Here is what I used for testing (Xamarin Android):

[Activity(Label = "@string/app_name", Theme = "@style/MyTheme")]

public class DatabaseSettingsActivity : Activity

{



    protected override void OnCreate(Bundle savedInstanceState)

    {

        base.OnCreate(savedInstanceState);

        SetContentView(Resource.Layout.yubichall_test);



        FindViewById<Button>(Resource.Id.btn_yubichall).Click += (sender, args) =>

        {



            byte challenge64 = new byte[64];

            for (int i = 0; i < 64; i++)

            {

                challenge64[i] = (byte) i;





            }

            var chalIntent = TryGetYubichallengeIntentOrPrompt(challenge64, true);



            StartActivityForResult(chalIntent, 123);



        };





        //Uncomment this and it will work

        /* if ((int)Build.VERSION.SdkInt >= 23)

            RequestPermissions(new { Manifest.Permission.UseFingerprint }, 99);*/

    }



    protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)

    {

        base.OnActivityResult(requestCode, resultCode, data);

        Kp2aLog.Log("OnActivityResult: " + requestCode);

        if (resultCode == Result.Ok)

        {

            byte challengeResponse = data.GetByteArrayExtra("response");

            if ((challengeResponse != null) && (challengeResponse.Length > 0))

            {

                FindViewById<TextView>(Resource.Id.text_result).Text =

                    MemUtil.ByteArrayToHexString(challengeResponse);



            }

        }

    }





    public Intent TryGetYubichallengeIntentOrPrompt(byte challenge, bool promptToInstall)

    {

        Intent chalIntent = new Intent("net.pp3345.ykdroid.intent.action.CHALLENGE_RESPONSE");

        chalIntent.PutExtra("challenge", challenge);



        IList<ResolveInfo> activities = PackageManager.QueryIntentActivities(chalIntent, 0);

        bool isIntentSafe = activities.Count > 0;

        if (isIntentSafe)

        {

            return chalIntent;

        }

        if (promptToInstall)

        {

            //please install https://play.google.com/store/apps/details?id=net.pp3345.ykdroid&hl=en

        }

        return null;

    }

}

where the layout yubicall_test is

    <?xml version="1.0" encoding="utf-8" ?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

              android:layout_width="fill_parent"

              android:orientation="vertical"

              android:layout_height="wrap_content">

  <Button android:id="@+id/btn_yubichall"

          android:layout_width="wrap_content"

          android:layout_height="wrap_content"

          android:text="yubi challenge"

  />



  <TextView

    android:id="@+id/text_result"

    android:layout_width="wrap_content"

    android:layout_height="wrap_content"

  />



</LinearLayout>