[英]Format & localize date labels in charts_flutter time series chart
我在charts_flutter 中有以下时间序列:
charts.Series<DatumPoint, DateTime>(
id: 'Series',
colorFn: (_, __) => charts.MaterialPalette.red.shadeDefault,
domainFn: (DatumPoint point, _) => point.date,
measureFn: (DatumPoint point, _) => point.value,
data: p,
)
这就是我的TimeSeriesChart
创建方式:
@override
Widget build(BuildContext context) {
return charts.TimeSeriesChart(
widget.seriesList,
animate: widget.animate,
selectionModels: [
charts.SelectionModelConfig(
type: charts.SelectionModelType.info,
changedListener: _onSelectionChanged,
)
],
domainAxis: charts.EndPointsTimeAxisSpec(),
behaviors: [
charts.LinePointHighlighter(
showHorizontalFollowLine:
charts.LinePointHighlighterFollowLineType.none,
showVerticalFollowLine:
charts.LinePointHighlighterFollowLineType.nearest,
dashPattern: [1, 1]),
charts.SelectNearest(
eventTrigger: charts.SelectionTrigger.tapAndDrag,
),
],
);
}
}
我想使用本地化DateTime
格式,例如DateFormat.yMMMd(Localizations.localeOf(context).languageCode).format(date)
格式化域DateFormat.yMMMd(Localizations.localeOf(context).languageCode).format(date)
开始和结束代码
我怎样才能做到这一点?
Shruti Gupta 的解决方案并不完整。 您必须使用自定义dateTimeFactory
来真正本地化日期。
所以创建你自己的DateTimeFactory
import 'package:charts_common/common.dart' as common show DateTimeFactory;
/// A class to localize the date
class LocalizedTimeFactory implements common.DateTimeFactory {
final Locale locale;
const LocalizedTimeFactory(this.locale);
DateTime createDateTimeFromMilliSecondsSinceEpoch(
int millisecondsSinceEpoch) {
return DateTime.fromMillisecondsSinceEpoch(millisecondsSinceEpoch);
}
DateTime createDateTime(int year,
[int month = 1,
int day = 1,
int hour = 0,
int minute = 0,
int second = 0,
int millisecond = 0,
int microsecond = 0]) {
return DateTime(
year, month, day, hour, minute, second, millisecond, microsecond);
}
/// Returns a [DateFormat].
DateFormat createDateFormat(String pattern) {
return DateFormat(pattern, locale.languageCode);
}
}
然后您需要添加一个tickFormatterSpec
以便您的自定义 dateTimeFactory 被考虑在内并填充dateTimeFactory
字段:
charts.TimeSeriesChart(data.seriesPressure(context),
defaultRenderer: charts.LineRendererConfig(includeArea: true, strokeWidthPx: 1),
animate: false,
domainAxis: new charts.DateTimeAxisSpec(
tickFormatterSpec: charts.AutoDateTimeTickFormatterSpec(
hour: new charts.TimeFormatterSpec(format: "Hm", transitionFormat: "Hm"),
),
),
dateTimeFactory: LocalizedTimeFactory(Localizations.localeOf(context)),
primaryMeasureAxis: charts.NumericAxisSpec(
tickProviderSpec: charts.BasicNumericTickProviderSpec(zeroBound: false))
),
您剩下的任务是更好地配置tickFormatterSpec
。 使用日期、小时和分钟字段,以及格式和转换格式,直到达到您想要的效果。 不幸的是,当没有 tickFormatterSpec 时,我无法复制显示...
你可以试试这个:
tickFormatterSpec: new charts.AutoDateTimeTickFormatterSpec( 月: new charts.TimeFormatterSpec( format: 'MMM', transitionFormat: 'MMM yy', ), year: new charts.TimeFormatterSpec( format: 'YYYY', transitionFormat: 'MMM yy', ) ),
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