How to Store locally Increment Counter in ListView? flutter - flutter

Question

I am talking an API request from website And there is an vote which I would like to locally store in flutter. I already implemented increment & decrement of votes but I want to store that votes locally in the phone, in a flutter.
How to locally store increment & decrement counter in listView?
class MoviesModel {
int vote;
MoviesModel({this.vote});
int increaseCounter() {
vote++;
return vote;
}
void decreaseCounter() {
if (vote > 0) {
vote--;
}
}
}
Below is the listView Builder
ListView.builder(
itemCount: _movies.length,
padding: EdgeInsets.all(4),
physics: BouncingScrollPhysics(),
itemBuilder: (context, index) {
final moviess = _movies[index];
return Column(
children: [
IconButton(
icon: Icon(
Icons.keyboard_arrow_up_outlined,
),
color: Colors.white,
onPressed: () async {
final prefs = await SharedPreferences
.getInstance();
setState(() {
final vote =
moviess.increaseCounter();
prefs.setInt('vote', vote);
print(vote);
});
},
),
SizedBox(
height: 10,
),
// moviess.vote.toString(),
Text(moviess.vote.toString() ?? " ",
style: TextStyle(
color: Colors.white,
fontSize: 20)),
SizedBox(
height: 10,
),
IconButton(
icon: Icon(
Icons.keyboard_arrow_down_outlined,
),
color: Colors.white,
onPressed: () {
setState(() {
moviess.decreaseCounter();
});
// decreaseCount();
},
),
],
);
}
),

Answer 1

First of all add shared_preferences.
Create a variable in your class as SharedPreferences prefs;
Initialise the instance in the initState() like: prefs = await SharedPreferences.getInstance()
When the counter is clicked / increased / decreased, save it like this:
await prefs.setInt('counter', counterValue);
When you open the app next time, check in the initState() if there is a value saved in preferences. If yes, then use that else use 0.
Example:
int counter = (prefs.getInt('counterValue') ?? 0);
Now use this counter variable to display text.

Answer 2

You can use shared_preferences
Future<void> _storeIncrement(int yourValue) async {
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setInt('counter', yourValue);
}
there is also more option to store as per your datatype as below
prefs.setBool(key, value)
prefs.setString(key, value)
prefs.setDouble(key, value)
prefs.setStringList(key, value)
below code is to get data
Future<void> _getIncrement() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
int storedValue = prefs.getInt('counter');
print('your data is $storedValue');
}
get data as per your datatype
prefs.getBool(key)
prefs.getString(key)
prefs.getDouble(key)
prefs.getStringList(key)