fixed login error handling

app/src/main/java/org/nuclearfog/twidda/activities/LoginActivity.java

@@ -187,7 +187,7 @@ public class LoginActivity extends AppCompatActivity implements OnClickListener
      *
      * @param error Twitter exception
      */
-    public void onError(TwitterError error) {
+    public void onError(@Nullable TwitterError error) {
         ErrorHandler.handleFailure(this, error);
     }
 

app/src/main/java/org/nuclearfog/twidda/backend/Registration.java

@@ -50,38 +50,43 @@ public class Registration extends AsyncTask<String, Void, String> {
     @Override
     protected String doInBackground(String... param) {
         try {
-            // check if we need to backup current session
-            if (settings.isLoggedIn() && !accountDB.exists(settings.getCurrentUserId())) {
-                accountDB.setLogin(settings.getCurrentUserId(), settings.getAccessToken(), settings.getTokenSecret());
-            }
             // no PIN means we need to request a token to login
             if (param.length == 0) {
+                // backup current login if exist
+                if (settings.isLoggedIn() && !accountDB.exists(settings.getCurrentUserId())) {
+                    accountDB.setLogin(settings.getCurrentUserId(), settings.getAccessToken(), settings.getTokenSecret());
+                }
                 return twitter.getRequestToken();
             }
-            // login with pin
+            // login with pin and access token
             User user = twitter.login(param[0], param[1]);
+            // save new user information
             database.storeUser(user);
+            accountDB.setLogin(user.getId(), settings.getAccessToken(), settings.getTokenSecret());
             return "";
         } catch (TwitterException exception) {
             this.exception = exception;
+            return null;
         }
-        return null;
     }
 
 
     @Override
-    protected void onPostExecute(String redirectionURL) {
+    protected void onPostExecute(String result) {
         LoginActivity activity = callback.get();
         if (activity != null) {
-            if (redirectionURL != null) {
-                if (!redirectionURL.isEmpty()) {
-                    activity.connect(redirectionURL);
-                } else if (exception != null) {
-                    activity.onError(exception);
-                } else {
+            // redirect to Twitter login page
+            if (result != null) {
+                if (result.isEmpty()) {
                     activity.onSuccess();
+                } else {
+                    activity.connect(result);
                 }
             }
+            // notify when an error occured
+            else {
+                activity.onError(exception);
+            }
         }
     }
 }

app/src/main/java/org/nuclearfog/twidda/backend/api/Twitter.java

@@ -184,6 +184,7 @@ public class Twitter implements GlobalSettings.SettingsListener {
             Response response = post(REQUEST_TOKEN, new ArrayList<>(1));
             if (response.code() == 200 && response.body() != null) {
                 String res = response.body().string();
+                // extrect oauth_token from url
                 Uri uri = Uri.parse(AUTHENTICATE + "?" + res);
                 return uri.getQueryParameter("oauth_token");
             }