flutter - 如何使用连续排序方法构建查询

Question

我在使用链接顺序方法构建查询时遇到错误，因为它的返回类型为 void。

  final qc =
        Entity_.objectID
            .equals(objectId)
            .and(Entity_.date
                .lessOrEqual(date.millisecondsSinceEpoch));

   final  QueryBuilder qBuilder = _box
        .query(qc)
        .order(DualPhaseOilWaterTankReadingData_.readingNumber)
        .order(DualPhaseOilWaterTankReadingData_.readingDate).build();

   
    List<Entity> data = qBuilder.find();
    qBuilder.close();
    return data

Answer 1

您可以使用特殊的 Dart 语法（级联表示法）来“链接order方法调用：

final QueryBuilder qBuilder = _box.query(qc)
  ..order(DualPhaseOilWaterTankReadingData_.readingNumber)
  ..order(DualPhaseOilWaterTankReadingData_.readingDate);
final query = qBuilder.build();