TextField value only updated when hovered - flutter

Question

I have a Category TextField with a controller. The controller value is updated onChange of a Product Dropdown. What I expect is upon onChange the value of the categoryField should be updated. However, I can only see the update on the TextField once I hover on it.
Category TextField
var productCategory = Column(
children: [
TextField(
controller: categoryController,
enabled: false,
focusNode: categoryFocusNode,
),
const Padding(
padding: EdgeInsets.all(5.0), child: SizedBox(width: 200)),
],
);
Product Dropdown onChange
void onChange<Product>(prod) {
BlocProvider.of<InvoiceCubit>(context).updateProduct(prod);
categoryController.text = prod.category.categoryName.toString();
}

Answer 1

I have finally figured it out. Since I am using a rxdart stream, I created both the Product dropdown and Category on the StreamBuilder. Then I created the categoryController within the builder itself with text value from the product category. Below is my code:
var productDropdownField = StreamBuilder<Product>(
stream: BlocProvider.of<InvoiceCubit>(context).productStream,
builder: (context, snapshot) {
final categoryController = TextEditingController();
categoryController.text = snapshot.hasData
? snapshot.data!.category.categoryName
: "";
var productCategory = Column(
children: [
CustomTextField(
labelText: "Category",
controller: categoryController,
enabled: false,
),
const Padding(
padding: EdgeInsets.all(10.0),
child: SizedBox(width: 200)),
],
);
return StreamBuilder<Object>(
stream:
BlocProvider.of<InvoiceCubit>(context).priceStream,
builder: (context, snapshot) {
return Column(
children: [
BlocBuilder<ProductsCubit, ProductsState>(
builder: (context, state) {
if (state is ProductsLoaded) {
List<DropdownMenuItem<Product>>
dropDownItems = state.products
.map((e) => DropdownMenuItem<Product>(
value: e,
child: Text(
e.productName,
style: const TextStyle(
color: Colors.black,
fontWeight:
FontWeight.w900),
),
))
.toList();
if (invoiceItem == null &&
prodSelected == false) {
onChange<Product>(state.products.first);
prodSelected = true;
}
return CustomDropdown<Product>(
labelText: "Product",
value:
BlocProvider.of<InvoiceCubit>(context)
.getProduct(),
items: dropDownItems,
context: context,
onChanged: onChange,
);
}
return const SizedBox(
width: 100, child: Text("Error"));
},
),
productCategory,
],
);
});
});
categoryController won't be updated via onChange but will be updated based on the snapshot.data