错误：无法弄清楚如何将该字段保存到数据库中

Question

我需要输入日历类型的转换器才能添加会议室数据库。

错误：

  

无法弄清楚如何将该字段保存到数据库中。您可以   考虑为其添加类型转换器。

Answer 1

在使用Room DB处理复杂数据时，您should write custom type converters。 请找到日期转换器的示例（它将日期转换为Long值并返回）：

class ReversingScrollNotificationFilter
    extends NotificationListener<ScrollNotification> {
  final bool reverse;
  final Widget child;

  ReversingScrollNotificationFilter({this.reverse = true, @required this.child})
      : super(
            onNotification: (scrollNotification) {
              print(scrollNotification.metrics.pixels);
              ScrollNotification newNotification;
              if (scrollNotification is ScrollStartNotification) {
                newNotification = ScrollStartNotification(
                    metrics: FixedScrollMetrics(
                        pixels: scrollNotification.metrics.maxScrollExtent -
                            scrollNotification.metrics.pixels,
                        axisDirection: scrollNotification.metrics.axisDirection,
                        minScrollExtent:
                            scrollNotification.metrics.minScrollExtent,
                        maxScrollExtent:
                            scrollNotification.metrics.maxScrollExtent,
                        viewportDimension:
                            scrollNotification.metrics.viewportDimension),
                    context: scrollNotification.context,
                    dragDetails: scrollNotification.dragDetails);
              } else {
                return false;
              }
              newNotification.dispatch(newNotification.context);
              return true; // cancel this notification because a new one was dispatched.
            },
            child: child);
}

此外，您可以参考this answer。