Fix AddCardFragment NPE on Configuration Change (#430)

* Fix issue that caused a NPE when accessing bundle arguments in AddCardFragment.

* Update bundle args to remove prefill card extra once it's applied.

* Update CHANGELOG.

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Braintree Android Drop-In Release Notes
 
+## unreleased
+
+* Reset bundle arguments for AddCardFragment after prefill card text is applied to Card Form (fixes #429)
+
 ## 6.11.0
 
 * Add California Privacy Laws notice of collection to credit card form

Drop-In/src/main/java/com/braintreepayments/api/AddCardFragment.java

@@ -23,6 +23,9 @@
 public class AddCardFragment extends DropInFragment implements OnCardFormSubmitListener,
         CardEditText.OnCardTypeChangedListener {
 
+    private static final String EXTRA_DROP_IN_REQUEST = "EXTRA_DROP_IN_REQUEST";
+    private static final String EXTRA_CARD_NUMBER = "EXTRA_CARD_NUMBER";
+
     @VisibleForTesting
     CardForm cardForm;
 
@@ -38,9 +41,9 @@ public class AddCardFragment extends DropInFragment implements OnCardFormSubmitL
 
     static AddCardFragment from(DropInRequest dropInRequest, @Nullable String cardNumber) {
         Bundle args = new Bundle();
-        args.putParcelable("EXTRA_DROP_IN_REQUEST", dropInRequest);
+        args.putParcelable(EXTRA_DROP_IN_REQUEST, dropInRequest);
         if (cardNumber != null) {
-            args.putString("EXTRA_CARD_NUMBER", cardNumber);
+            args.putString(EXTRA_CARD_NUMBER, cardNumber);
         }
 
         AddCardFragment instance = new AddCardFragment();
@@ -119,9 +122,13 @@ public void onResume() {
                 cardForm.getCardEditText().setText(cardNumber);
                 CardType cardType = cardForm.getCardEditText().getCardType();
                 onCardTypeChanged(cardType);
+
+                // reset bundle args to prevent existing input from being overriden
+                // when the fragment is re-created (e.g. on configuration change)
+                Bundle newArgs = new Bundle();
+                newArgs.putString(EXTRA_DROP_IN_REQUEST, args.getString(EXTRA_DROP_IN_REQUEST));
+                setArguments(newArgs);
             }
-            // prevent card number from overriding existing input
-            setArguments(null);
         }
     }