fix: 5627 - remove focus from price amount after adding product (open…

…foodfacts#5729)

packages/smooth_app/lib/pages/prices/price_add_product_card.dart

@@ -24,6 +24,17 @@ class _PriceAddProductCardState extends State<PriceAddProductCard> {
 
   String? _latestScannedBarcode;
 
+  // we create dummy focus nodes to focus on, when we need to unfocus.
+  final List<FocusNode> _dummyFocusNodes = <FocusNode>[];
+
+  @override
+  void dispose() {
+    for (final FocusNode focusNode in _dummyFocusNodes) {
+      focusNode.dispose();
+    }
+    super.dispose();
+  }
+
   @override
   Widget build(BuildContext context) {
     final AppLocalizations appLocalizations = AppLocalizations.of(context);
@@ -109,6 +120,13 @@ class _PriceAddProductCardState extends State<PriceAddProductCard> {
         ),
       ),
     );
+
+    // unfocus from the previous price amount text field.
+    // looks like the most efficient way to unfocus: focus somewhere in space...
+    final FocusNode focusNode = FocusNode();
+    _dummyFocusNodes.add(focusNode);
+    FocusScope.of(context).requestFocus(focusNode);
+
     priceModel.notifyListeners();
   }