How to store a List in Hive (Flutter)? - flutter

Question

I am trying to store and fetch a list using Hive in Flutter, however I get a range error.
int steps = 0;
List<int> stepCountList = List(7);
var time = DateTime.now();
// This is my method for a listener that updates when it detects a change,
void _onData(int newValue) async {
fetchSteps();
steps = stepCountList[time.weekday] ?? 0;
stepDivider += newValue;
stepCountList.insert(time.weekday - 1, steps);
moneyLottoBox.put('stepCountList', stepCountList);
}
void fetchSteps() {
stepCountList = moneyLottoBox.get('stepCountList');
if (stepCountList == null) {
moneyLottoBox.put('stepCountList', <int>[7]);
stepCountList = moneyLottoBox.get('stepCountList');
}
}
// I create my MoneyLotto box here,
var moneyLottoBox = Hive.box('moneyLottoBox');
Future<void> main async {
moneyLottoBox = await Hive.openBox('box');
}
Today being Saturday for me, the value of time.weekday for me is 6, however it shows me the error when I try to print(stepCountList[6])
RangeError (index): Invalid value: Only valid value is 0: 6

Answer 1

You can't use insert() method on fixed length List, by fixed length I mean when you declare it this way List<int> stepCountList = List(7);
Edited the code, now it should work
void _onData(int newValue) async {
fetchSteps();
steps = stepCountList[time.weekday] ?? 0;
stepDivider += newValue;
//stepCountList.insert(time.weekday - 1, steps);this is not correct
stepCountList[time.weekday -1] = steps; // this should be the approach
moneyLottoBox.put('stepCountList', stepCountList);
}
void fetchSteps() {
stepCountList = moneyLottoBox.get('stepCountList');
if (stepCountList == null) {
/* moneyLottoBox.put('stepCountList', <int>[7]); this statement is the
reason for your error because your are storing a growable list instead of fixed list in the hive */
moneyLottoBox.put('stepCountList', List<int>(7));// try this instead
// or u can use this moneyLottoBox.put('stepCountList', stepCountList);
stepCountList = moneyLottoBox.get('stepCountList');
}
}

Answer 2

Hive box has methods like: put(dynamic key, E value), putAll(Map<dynamic, E> entries) and putAt(int index, E value). For example, I used putAt() to update entry at the specific key.
For adding with auto-increment key, you want to use add(E value) or to add a list - addAll(Iterable<E> values).
And when I wanted to delete all data in the box, I used clear(), like so:
await _booksBox.clear();
And this method is for getting all the entries from the database:
List<Book> getAllBooks() {
return _booksBox.values.map(_bookFromDb).toList();
}
A complete Hive db class is from the tutorial.