Add counter on comment form

lib/ui/screens/conversation_screen.dart

@@ -325,15 +325,8 @@ class _ConversationScreenState extends State<ConversationScreen> {
               maxLengthEnforced: true,
 
               // Show max length only when there is some text already typed
-              buildCounter: (
-                BuildContext context, {
-                @required int currentLength,
-                @required int maxLength,
-                @required bool isFocused,
-              }) =>
-                  currentLength > 0
-                      ? Text("$currentLength/$maxLength")
-                      : Container(),
+              buildCounter: smartInputCounterWidgetBuilder,
+
               enabled: !_isSendingMessage,
               controller: _textEditingController,
               onChanged: _updatedText,

lib/ui/tiles/post_tile.dart

@@ -250,27 +250,33 @@ class _PostTileState extends State<PostTile> {
           // Comment input
           Expanded(
             child: TextField(
+              // Comment max size
+              maxLength: 255,
+              maxLines: null,
+              buildCounter: smartInputCounterWidgetBuilder,
+
               controller: _commentController,
               onChanged: (s) => setState(() {}),
               onSubmitted: _canSubmitComment ? (s) => _submitComment() : null,
               decoration: InputDecoration(
-                  hintText: tr("New comment..."),
-                  hintStyle: TextStyle(color: Colors.grey, fontSize: 12),
-                  fillColor: Colors.white,
-                  filled: true,
-                  border: OutlineInputBorder(
-                      borderSide: BorderSide(width: 0.5, color: Colors.grey),
-                      borderRadius: BorderRadius.only(
-                        topLeft: Radius.circular(3),
-                        bottomLeft: Radius.circular(3),
-                      ),
-                      gapPadding: 1),
-                  contentPadding: EdgeInsets.only(
-                    left: 10,
-                    right: 10,
-                    bottom: 5,
-                    top: 5,
-                  )),
+                hintText: tr("New comment..."),
+                hintStyle: TextStyle(color: Colors.grey, fontSize: 12),
+                fillColor: Colors.white,
+                filled: true,
+                border: OutlineInputBorder(
+                    borderSide: BorderSide(width: 0.5, color: Colors.grey),
+                    borderRadius: BorderRadius.only(
+                      topLeft: Radius.circular(3),
+                      bottomLeft: Radius.circular(3),
+                    ),
+                    gapPadding: 1),
+                contentPadding: EdgeInsets.only(
+                  left: 10,
+                  right: 10,
+                  bottom: 5,
+                  top: 5,
+                ),
+              ),
             ),
           ),
 

lib/utils/ui_utils.dart

@@ -153,3 +153,13 @@ Future<bool> showConfirmDialog({
 
   return result != null && result;
 }
+
+/// Smart [InputCounterWidgetBuilder] that show text limit only when some
+/// text has already been entered by the user
+Widget smartInputCounterWidgetBuilder(
+  BuildContext context, {
+  @required int currentLength,
+  @required int maxLength,
+  @required bool isFocused,
+}) =>
+    currentLength > 0 ? Text("$currentLength/$maxLength") : Container();