Fix NfcActivity task stack problem

OpenKeychain/src/main/AndroidManifest.xml

@@ -620,9 +620,18 @@
         <activity
             android:name=".ui.PassphraseDialogActivity"
             android:theme="@android:style/Theme.NoDisplay" />
+        <!--
+        NOTE: singleTop is set to get NFC foreground dispatch to work.
+              Then, all NFC intents will be broadcasted to onNewIntent() of this activity!
+              If more than one task stack of OpenKeychain exists, the broadcast
+              restarts the activity with onCreate() instead of calling onNewIntent().
+              taskAffinity and allowTaskReparenting somehow prevents this from happening!
+         -->
         <activity
             android:name=".ui.NfcActivity"
-            android:launchMode="singleTop" />
+            android:launchMode="singleTop"
+            android:taskAffinity=":Nfc"
+            android:allowTaskReparenting="true" />
         <activity
             android:name=".ui.HelpActivity"
             android:label="@string/title_help" />

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/remote/OpenPgpService.java

@@ -194,7 +194,6 @@ public class OpenPgpService extends RemoteService {
 
         intent.putExtra(NfcActivity.EXTRA_NFC_HASH_TO_SIGN, hashToSign);
         intent.putExtra(NfcActivity.EXTRA_NFC_HASH_ALGO, hashAlgo);
-        intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
         PendingIntent pi = PendingIntent.getActivity(getBaseContext(), 0,
                 intent,
                 PendingIntent.FLAG_CANCEL_CURRENT);
@@ -215,7 +214,6 @@ public class OpenPgpService extends RemoteService {
         intent.putExtra(NfcActivity.EXTRA_PIN, pin);
 
         intent.putExtra(NfcActivity.EXTRA_NFC_ENC_SESSION_KEY, encryptedSessionKey);
-        intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
         PendingIntent pi = PendingIntent.getActivity(getBaseContext(), 0,
                 intent,
                 PendingIntent.FLAG_CANCEL_CURRENT);

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/DecryptFragment.java

@@ -97,7 +97,6 @@ public abstract class DecryptFragment extends Fragment {
         intent.putExtra(NfcActivity.EXTRA_PIN, pin);
 
         intent.putExtra(NfcActivity.EXTRA_NFC_ENC_SESSION_KEY, encryptedSessionKey);
-        intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
 
         startActivityForResult(intent, REQUEST_CODE_NFC_DECRYPT);
     }

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/EncryptActivity.java

@@ -40,7 +40,6 @@ public abstract class EncryptActivity extends DrawerActivity {
         intent.putExtra(NfcActivity.EXTRA_PIN, pin);
         intent.putExtra(NfcActivity.EXTRA_NFC_HASH_TO_SIGN, hashToSign);
         intent.putExtra(NfcActivity.EXTRA_NFC_HASH_ALGO, hashAlgo);
-        intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
 
         startActivityForResult(intent, REQUEST_CODE_NFC);
     }

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/NfcActivity.java

@@ -111,9 +111,8 @@ public class NfcActivity extends ActionBarActivity {
             Log.d(Constants.TAG, "NfcActivity mEncryptedSessionKey as hex: " + getHex(mEncryptedSessionKey));
             Log.d(Constants.TAG, "NfcActivity mServiceIntent: " + mServiceIntent.toString());
         } else if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
-            Log.e(Constants.TAG, "This should not happen, but there is a bug in Android!");
+            Log.e(Constants.TAG, "This should not happen! NfcActivity.onCreate() is being called instead of onNewIntent()!");
-
+            toast("This should not happen! Please create a new bug report that the NFC screen is restarted!");
-            toast("This should not happen, but there is a bug in Android! Clear all app tasks and start app from launcher again!");
             finish();
         } else {
             Log.d(Constants.TAG, "Action not supported: " + action);