如何在flutter中存储列表？

3mpgtkmj 于 2021-06-24 发布在 Hive

关注(0)|答案(1)|浏览(395)

我正在尝试使用 Hive 然而，在Flutter中，我得到了一个距离误差。

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');
}

今天对我来说是星期六 time.weekday 对我来说是6，但是当我试着 print(stepCountList[6]) ```
RangeError (index): Invalid value: Only valid value is 0: 6

flutter dart flutter-hive

来源：https://stackoverflow.com/questions/62609037/how-to-store-a-list-in-flutter

1条答案

按热度按时间

iklwldmw1#

你不能使用 insert() 方法在固定长度列表中，固定长度的意思是当您这样声明它时 List<int> stepCountList = List(7); 编辑了代码，现在应该可以了

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');
    }
  }

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如何在flutter中存储列表？

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