catch EnableForegroundDispatch exception. disable

back button on yubikey 2fa.

src/Android/MainActivity.cs

@@ -233,9 +233,13 @@ namespace Bit.Android
                 ndef.AddDataScheme("https");
                 var filters = new IntentFilter[] { ndef };
 
+                try
+                {
                     // register for foreground dispatch so we'll receive tags according to our intent filters
                     adapter.EnableForegroundDispatch(this, pendingIntent, filters, null);
                 }
+                catch { }
+            }
             else
             {
                 adapter.DisableForegroundDispatch(this);

src/App/Pages/LoginTwoFactorPage.cs

@@ -335,6 +335,17 @@ namespace Bit.App.Pages
             MessagingCenter.Unsubscribe<Application>(Application.Current, "ResumeYubiKey");
         }
 
+        protected override bool OnBackButtonPressed()
+        {
+            // ref: https://github.com/bitwarden/mobile/issues/350
+            if(Device.RuntimePlatform == Device.Android && _providerType.HasValue &&
+                _providerType.Value == TwoFactorProviderType.YubiKey)
+            {
+                return true;
+            }
+            return base.OnBackButtonPressed();
+        }
+
         private async void AnotherMethodAsync()
         {
             var beforeProviderType = _providerType;