Riverpod state change methods not changing the state as intended

So I have a state in riverpod which holds a List of sets then I have two methods that make it a List of all the sets in the database and another that makes the state only today sets as follows:

u/riverpod
class SetsProvider extends _$SetsProvider {
u/override
List<Set> build() {
return [];
}
void refresh() async {
final data = await SQLHelper.getAllSets();
state = data.map((e) => Set.fromJson(e)).toList();
}
void getTodaySets() async {
final data = await SQLHelper.getTodayItems();
state = data.map((e) => Set.fromJson(e)).toList();
}

When I call

final list = ref.watch(setsProviderProvider);  

it works perfectly

But when I try to change the state to return only todays items it just doesn't work:

  ref.read(setsProviderProvider.notifier).getTodaySets();

it just makes my list empty when I watch the setProvider after that. What could I be doing wrong?

here is my dbhelper class:

import 'package:flutter/material.dart';
import 'package:sqflite/sqflite.dart' as sql;
import 'set_model.dart';
import 'package:intl/intl.dart';
class SQLHelper {
//method to create table
static Future<void> createTables(sql.Database database) async {
await database.execute("""CREATE TABLE sets(
id INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL,
exerciseName TEXT,
totalWeight TEXT,
totalReps TEXT,
date TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
isFavorited INTEGER 
)
""");
print('Database created');
}
//method to open the database called db
static Future<sql.Database> db() async {
return sql.openDatabase('dbsets.db', version: 1,
onCreate: (sql.Database database, int version) async {
await createTables(database); //calling that create table method above
});
}
static Future<int> insertSet(Set set) async {
final db = await SQLHelper.db(); //opening the database
DateTime now = DateTime.now();
String formattedDate = DateFormat('yyyy-MM-dd').format(now);
//Changing the Date to now meaning ill make the date not required in a Set object
set.date == formattedDate;
final id = await db.insert('sets', set.toJson(), //toJson calls the map
conflictAlgorithm: sql.ConflictAlgorithm.replace);
return id;
}
static Future<List<Map<String, dynamic>>> getAllSets() async {
final db = await SQLHelper.db();
return db.query('sets', orderBy: 'id');
}
static Future<List<Map<String, dynamic>>> getTodayItems() async {
final db = await SQLHelper.db(); //get connection
DateTime now = DateTime.now();
String formattedDate = DateFormat('yyyy-MM-dd').format(now);
final results =
db.rawQuery('SELECT * FROM sets WHERE date = ?', [formattedDate]);
print(results.toString());
return results;
}
}

And where I am trying to show the sets in Main.dart:

   child: ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemCount: ref.watch(setsProviderProvider).length,
itemBuilder: ((_, index) {
ref.read(setsProviderProvider.notifier).getTodaySets();
final list = ref.watch(setsProviderProvider);
var set = list[index];
return ListTile(
title: Text(set.exerciseName.toString()),
subtitle: Column(
children: [
Text(
set.totalWeight.toString(),
),
Text(
set.totalReps.toString(),
)
],
),
);
}),
),

First don't put database calls in during build, it might run multiple time.
You could put it in places such as initState or main().

The list didn't update because the initial list is empty, itemCount is 0, so item builder of ListView is never called.

Update: I meant Widget.build, not provider build. The best practice is to call it in provider's build, but this would also change the provider to async provider.

itemBuilder: ((_, index) {
ref.read(setsProviderProvider.notifier).getTodaySets(); // <- This shouldn't be here/
final list = ref.watch(setsProviderProvider);
</details>
# 答案2
**得分**: 0
你应该让筛选提供程序*监视*完整列表提供程序，同时将筛选参数作为家庭键。然后，当你更新完整列表提供程序（无论是来自本地变更还是观察数据库流），筛选提供程序将具有正确的值，并在被监视时进行缓存。
<details>
<summary>英文:</summary>
You should have the filter provider *watch* the full-list provider, as well as take a filter argument as a family key.  Then, as you update the full-list provider (either from local mutations, or from watching a database stream), the filter provider(s) will have the proper value, caching as long as they are being watched.
</details>