How can I keep my content when swapping tabs on flutter?

I lost my information when I change the tab

I was trying to keep information with a provider but when I change to another my information get lost this is my code. I don't know how to keep all the content, if you guys need more code say it and I post the rest of the code.
Right now this is the only problem that I can find on the code but I think there's more problems on it.

import 'package:provider/provider.dart';
import '../../providers/item_provider.dart';
import '../../search/product_search.dart';
import '../../models/product.dart';

class Busqueda extends StatefulWidget {
  final TabController tabController;

  const Busqueda(this.tabController);

  @override
  State<Busqueda> createState() => _BusquedaState();
}

class _BusquedaState extends State<Busqueda> {
  late Product productoSeleccionado = Product(
      fotoUrl: '',
      itemId: 0,
      codItem: '',
      descripcion: '',
      monedaId: 0,
      precioVentaActual: 0,
      existenciaActual: 0,
      precioIvaIncluido: 0,
      existenciaTotal: 0,
      ivaId: 0,
      valor: 0);
  List<Product> historial = [];

  Widget historialProducts(List<Product> products){
    return ListView.builder(
      itemCount: products.length,
      itemBuilder: (context, i){

        final producto = products[i];
        return ListTile(
          title: Text(context.watch<ItemProvider>().product.descripcion),
          subtitle: Text(producto.codItem),
          trailing: Text(producto.precioVentaActual.toString()),
        );
      }
    );
  }


  @override
  Widget build(BuildContext context) {
    return Center(
      child: Column(
        children: [
          Padding(
            padding: const EdgeInsets.all(8.0),
            child: SearchBar(
              hintText: context.watch<ItemProvider>().product.descripcion.toString(),
              textStyle: MaterialStatePropertyAll(TextStyle(color: Colors.grey)),
              onTap: () async {
                final producto = await showSearch(
                    context: context,
                    delegate:
                        ProductSearchDelegate('Buscar Producto', historial));
                if (producto != null) {
                  setState(() {
                    productoSeleccionado = producto;
                    final int productoExiste = historial.indexWhere(
                      (element) => element.codItem == producto.codItem);
                    if (productoExiste == -1) {
                      historial.insert(0, producto);
                    }
                    context.read<ItemProvider>().setProduct(producto);
                    widget.tabController.animateTo(2);
                  });
                }
              },
            ),
          ),
          Expanded(
            child: historialProducts(this.historial)
          )
        ],
      ),
    );
  }
}```

</details>


# 答案1
**得分**: 1

Here is the translated code portion:

```dart
你可以尝试使用这个小部件;

class KeepAlivePage extends StatefulWidget {
  const KeepAlivePage({Key? key, required this.child, required this.keepAlive}) : super(key: key);

  final Widget child;
  final bool keepAlive;

  @override
  State<KeepAlivePage> createState() => _KeepAlivePageState();
}

class _KeepAlivePageState extends State<KeepAlivePage> with AutomaticKeepAliveClientMixin {
  @override
  Widget build(BuildContext context) {
    super.build(context);
    return widget.child;
  }

  @override
  bool get wantKeepAlive => widget.keepAlive;
}

你可以像这样使用它;

Expanded(
  child: TabBarView(
    controller: tabController,
    children: const [
      KeepAlivePage(keepAlive: true, child: Tab1()),
      KeepAlivePage(keepAlive: true, child: Tab2()),
    ],
  ),
 ),

Please let me know if you need any further assistance or have more questions!

class KeepAlivePage extends StatefulWidget {
  const KeepAlivePage({Key? key, required this.child, required this.keepAlive}) : super(key: key);

  final Widget child;
  final bool keepAlive;

  @override
  State<KeepAlivePage> createState() => _KeepAlivePageState();
}

class _KeepAlivePageState extends State<KeepAlivePage> with AutomaticKeepAliveClientMixin {
  @override
  Widget build(BuildContext context) {
    super.build(context);
    return widget.child;
  }

  @override
  bool get wantKeepAlive => widget.keepAlive;
}

Expanded(
  child: TabBarView(
    controller: tabController,
    children: const [
      KeepAlivePage(keepAlive: true, child: Tab1()),
      KeepAlivePage(keepAlive: true, child: Tab2()),
    ],
  ),
 ),