How to add search history functionality in flutter app - flutter

Question

I have recently add search functionality in flutter app and I want to add search history functionality in my flutter app. I am stuck in this I have no idea that how to add it.
Please give me instuction and also provide suitable code for it .
My code
TextFormField(
keyboardType: TextInputType.text,
textInputAction: TextInputAction.search,
controller: searchcontroller,
focusNode: fousnode,
onChanged: (query) {
setState(() {
FirebaseFirestore.instance
.collectionGroup("Add_product")
.where("product_name", isGreaterThanOrEqualTo: query)
.where("product_name", isLessThan: query + 'z')
.snapshots();
});
},
decoration: InputDecoration(
hintText: "Search Product",
border: OutlineInputBorder(
borderRadius: BorderRadius.all(Radius.circular(11)),
),
),
)
StreamBuilder(
stream:
FirebaseFirestore.instance.collectionGroup("Add_product").snapshots(),
builder: (BuildContext context,
AsyncSnapshot<QuerySnapshot> snapshot) {
List<QueryDocumentSnapshot> data = snapshot.data!.docs;
if (searchcontroller.text.isNotEmpty) {
data = data.where((doc) => doc["product_name"]
.toLowerCase()
.contains(searchcontroller.text.toLowerCase()))
.toList();
}
return GridView.builder(
itemCount:data.length,
itemBuilder: (itemBuilder, index) {
return Container(
child: InkWell(
onTap: (){
Navigator.push(context, MaterialPageRoute(builder: (builder)=>detail(
url: snapshot.data!.docs[index]["url"],
productName: snapshot.data!.docs[index]["product_name"],
productPrice: snapshot.data!.docs[index]["product_price"],
)));
},
child: ListTile(
leading: CircleAvatar(
backgroundImage: NetworkImage(
snapshot.data!.docs[index]["url"]
),
),
title: Text(snapshot.data!.docs[index]["product_name"])
),
),
),
);
},
);
}),

Answer 1

every time a search is performed you can create a list or a map and save it locally or in the database according to your needs. To then make the data that you are going to recover appear under the search bar, I recommend using existing plugins such as material_floating_search_bar
example with shared preferences (locally):
final prefs = await SharedPreferences.getInstance();
List<String> _currentResearch = prefs.getStringList("searches") ?? [];
_currentResearch.add(searchcontroller.text);
await prefs.setStringList("searches", _ricercheAttuali);