Better YubiKey UX flow for error handling

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

@@ -9,7 +9,9 @@ package org.sufficientlysecure.keychain.ui;
 import android.content.Intent;
 import android.os.AsyncTask;
 import android.os.Bundle;
+import android.view.View;
 import android.view.WindowManager;
+import android.widget.Button;
 import android.widget.TextView;
 import android.widget.ViewAnimator;
 
@@ -49,6 +51,7 @@ public class NfcOperationActivity extends BaseNfcActivity {
 
     public ViewAnimator vAnimator;
     public TextView vErrorText;
+    public Button vErrorTryAgainButton;
 
     private RequiredInputParcel mRequiredInput;
     private Intent mServiceIntent;
@@ -68,7 +71,20 @@ public class NfcOperationActivity extends BaseNfcActivity {
 
         vAnimator = (ViewAnimator) findViewById(R.id.view_animator);
         vAnimator.setDisplayedChild(0);
-        vErrorText = (TextView) findViewById(R.id.nfc_activity_error_text);
+        vErrorText = (TextView) findViewById(R.id.nfc_activity_3_error_text);
+        vErrorTryAgainButton = (Button) findViewById(R.id.nfc_activity_3_error_try_again);
+        vErrorTryAgainButton.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                resumeTagHandling();
+
+                // obtain passphrase for this subkey
+                if (mRequiredInput.mType != RequiredInputParcel.RequiredInputType.NFC_MOVE_KEY_TO_CARD) {
+                    obtainYubiKeyPin(mRequiredInput);
+                }
+                vAnimator.setDisplayedChild(0);
+            }
+        });
 
         Intent intent = getIntent();
         Bundle data = intent.getExtras();
@@ -84,7 +100,7 @@ public class NfcOperationActivity extends BaseNfcActivity {
 
     @Override
     protected void initLayout() {
-        setContentView(R.layout.nfc_activity);
+        setContentView(R.layout.nfc_operation_activity);
     }
 
     @Override
@@ -221,8 +237,7 @@ public class NfcOperationActivity extends BaseNfcActivity {
                     if (isNfcConnected()) {
                         try {
                             Thread.sleep(200);
-                        } catch (InterruptedException e) {
-                            // never mind
+                        } catch (InterruptedException ignored) {
                         }
                     } else {
                         return null;
@@ -239,7 +254,9 @@ public class NfcOperationActivity extends BaseNfcActivity {
 
     @Override
     protected void onNfcError(String error) {
-        vErrorText.setText(error);
+        pauseTagHandling();
+
+        vErrorText.setText(error + "\n\n" + getString(R.string.nfc_try_again_text));
         vAnimator.setDisplayedChild(3);
     }
 
@@ -270,8 +287,6 @@ public class NfcOperationActivity extends BaseNfcActivity {
         // clear (invalid) passphrase
         PassphraseCacheService.clearCachedPassphrase(
                 this, mRequiredInput.getMasterKeyId(), mRequiredInput.getSubKeyId());
-
-        obtainYubiKeyPin(mRequiredInput);
     }
 
 }

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/BaseNfcActivity.java

@@ -29,6 +29,7 @@ import android.content.Intent;
 import android.content.IntentFilter;
 import android.nfc.NfcAdapter;
 import android.nfc.Tag;
+import android.nfc.TagLostException;
 import android.nfc.tech.IsoDep;
 import android.os.AsyncTask;
 import android.os.Bundle;
@@ -72,6 +73,7 @@ public abstract class BaseNfcActivity extends BaseActivity {
     protected boolean mPw3Validated;
     private NfcAdapter mNfcAdapter;
     private IsoDep mIsoDep;
+    private boolean mTagHandlingEnabled;
 
     private static final int TIMEOUT = 100000;
 
@@ -168,10 +170,20 @@ public abstract class BaseNfcActivity extends BaseActivity {
         }.execute();
     }
 
+    protected void pauseTagHandling() {
+        mTagHandlingEnabled = false;
+    }
+
+    protected void resumeTagHandling() {
+        mTagHandlingEnabled = true;
+    }
+
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
+        mTagHandlingEnabled = true;
+
         Intent intent = getIntent();
         String action = intent.getAction();
         if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(action)) {
@@ -186,7 +198,8 @@ public abstract class BaseNfcActivity extends BaseActivity {
      */
     @Override
     public void onNewIntent(final Intent intent) {
-        if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())) {
+        if (NfcAdapter.ACTION_TAG_DISCOVERED.equals(intent.getAction())
+                && mTagHandlingEnabled) {
             handleIntentInBackground(intent);
         }
     }
@@ -194,6 +207,11 @@ public abstract class BaseNfcActivity extends BaseActivity {
     private void handleNfcError(Exception e) {
         Log.e(Constants.TAG, "nfc error", e);
 
+        if (e instanceof TagLostException) {
+            onNfcError(getString(R.string.error_nfc_tag_lost));
+            return;
+        }
+
         short status;
         if (e instanceof CardException) {
             status = ((CardException) e).getResponseCode();
@@ -202,7 +220,8 @@ public abstract class BaseNfcActivity extends BaseActivity {
         }
         // When entering a PIN, a status of 63CX indicates X attempts remaining.
         if ((status & (short)0xFFF0) == 0x63C0) {
-            onNfcError(getString(R.string.error_pin, status & 0x000F));
+            int tries = status & 0x000F;
+            onNfcError(getResources().getQuantityString(R.plurals.error_pin, tries, tries));
             return;
         }