Can create a new choice for the survey

lib/helpers/survey_helper.dart

@@ -34,7 +34,18 @@ class SurveyHelper {
         .isOK;
   }
 
+  /// Create a new choice in a survey
+  ///
+  /// Throws in case of failure
+  static Future<void> createNewChoice(int postID, String newChoice) async =>
+      await APIRequest.withLogin("surveys/create_new_choice")
+          .addInt("postID", postID)
+          .addString("choice", newChoice)
+          .execWithThrow();
+
   /// Prevent new choices from being created on a survey
+  ///
+  /// Throws in case of failure
   static Future<void> blockNewChoicesCreation(int postID) async =>
       await APIRequest.withLogin("surveys/block_new_choices_creation")
           .addInt("postID", postID)

lib/ui/widgets/survey_widget.dart

@@ -44,6 +44,9 @@ class _SurveyWidgetState extends SafeState<SurveyWidget> {
         ),
         _buildUserResponse(),
 
+        // Offer the user to create a new choice on the survey, if possible
+        survey.allowNewChoicesCreation ? _buildNewChoiceLink() : Container(),
+
         // Offer to block the creation of new responses, if possible
         survey.canBlockNewChoicesCreation
             ? _buildBlockNewResponsesLink()
@@ -116,9 +119,20 @@ class _SurveyWidgetState extends SafeState<SurveyWidget> {
     );
   }
 
-  Widget _buildBlockNewResponsesLink() => InkWell(
+  Widget _buildNewChoiceLink() => Padding(
-        onTap: _blockNewChoices,
+        padding: const EdgeInsets.all(8.0),
-        child: Text(tr("Block the creation of new responses")),
+        child: InkWell(
+          onTap: _createNewChoices,
+          child: Text(tr("Create a new choice")),
+        ),
+      );
+
+  Widget _buildBlockNewResponsesLink() => Padding(
+        padding: const EdgeInsets.all(8.0),
+        child: InkWell(
+          onTap: _blockNewChoices,
+          child: Text(tr("Block the creation of new responses")),
+        ),
       );
 
   Widget _buildChart() {
@@ -146,6 +160,30 @@ class _SurveyWidgetState extends SafeState<SurveyWidget> {
     });
   }
 
+  /// Create a new choice
+  void _createNewChoices() async {
+    try {
+      final newChoice = await askUserString(
+        context: context,
+        title: tr("New choice"),
+        message: tr("Please specify the new choice for the survey"),
+        defaultValue: "",
+        hint: tr("New choice..."),
+        maxLength: 50,
+      );
+
+      if (newChoice == null || newChoice.isEmpty) return;
+
+      await SurveyHelper.createNewChoice(survey.postID, newChoice);
+
+      // TODO : reload survey
+    } catch (e, s) {
+      print("Could not create new survey choice! $e\n$s");
+      showSimpleSnack(
+          context, tr("Could not create a new choice for this survey!"));
+    }
+  }
+
   /// Block the creation of new choices on this survey
   void _blockNewChoices() async {
     try {