显示没有数据的文本小部件，用于零值同步叠加条形图颤振的条形图。

Question

需要显示无数据可用文本代替条形图中的零值，y轴标签为字符串，x轴为整数，请参阅下面的第一幅图像为尖锐结果，第二幅图像为预期结果。第一张图像中，具有零值的空位置而不是空位置需要显示没有数据的可用文本。

    SfCartesianChart(
            crosshairBehavior: _crosshairBehavior,
            primaryXAxis: CategoryAxis(
                majorTickLines: MajorTickLines(size: 20, width: 0),
                axisBorderType: AxisBorderType.withoutTopAndBottom,
                labelAlignment: LabelAlignment.center,
                borderWidth: 2.0,
                labelStyle: TextStyle(
                    fontFamily: 'Roboto',
                    fontSize: 14,
                    fontStyle: FontStyle.normal,
                    fontWeight: FontWeight.w500),
                //maximumLabelWidth: 100,
                labelPosition: ChartDataLabelPosition.outside,
                borderColor: Colors.blueGrey[800]),
            primaryYAxis: CategoryAxis(
              plotBands: <PlotBand>[
                PlotBand(
                  isVisible: widget.isFleetAverageVisible,
                  start: 30,
                  end: 29,
                  borderWidth: 0.3,
                  borderColor: Colors.black,
                )
              ],
              interval: 25,
              maximumLabels: 4,
              maximum: 100,
              minimum: 0,
              majorTickLines: MajorTickLines(size: 15, width: 0),
              majorGridLines: MajorGridLines(dashArray: [5, 5]),
            ),
            series: stackedWidget(sortSelected != null
                ? sortSelected == true
                    ? SortingOrder.ascending
                    : SortingOrder.descending
                : SortingOrder.none),
            legend: Legend(
              isVisible: true,
              position: LegendPosition.bottom,
              overflowMode: LegendItemOverflowMode.wrap,
            ),
            onLegendTapped: (LegendTapArgs args) {
    
              },
          ),
       
   

    List<ChartSeries> stackedWidget(SortingOrder sortingOrder) {
  return <ChartSeries>[
    StackedBarSeries<ChartData, String>(
        sortingOrder: sortingOrder,
        legendIconType: LegendIconType.horizontalLine,
        legendItemText: "series1",
        width: 0.3,
        spacing: 0.2,
        dataSource: chartData,
        //list of data
        xValueMapper: (ChartData data, _) => data.x,
        yValueMapper: (ChartData data, _) => data.y1,
        sortFieldValueMapper: (ChartData sales, _) => sales.y1,
        color: Color.fromRGBO(51, 102, 255, 1))
  ];
}

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Answer 1

尝试将DataLabelSettings()授予StackedBarSeries()上的dataLabelSettings:属性

List<ChartSeries> stackedWidget(SortingOrder sortingOrder) {
  return <ChartSeries>[
    StackedBarSeries<ChartData, String>(
        dataLabelSettings: DataLabelSettings(
          builder: (
              data,
              point,
              series,
              pointIndex,
              seriesIndex,
              ) {
            if (chartData[pointIndex].y == 0 || chartData[pointIndex].y == null) {
              return Row(children: const [
                Icon(Icons.warning_amber_outlined),
                Text("No data available"),
              ]);
            } else {
              return const SizedBox();
            }
          },
          isVisible: true,
        ),
        sortingOrder: sortingOrder,
        legendIconType: LegendIconType.horizontalLine,
        legendItemText: "series1",
        width: 0.3,
        spacing: 0.2,
        dataSource: chartData,
        //list of data
        xValueMapper: (ChartData data, _) => data.x,
        yValueMapper: (ChartData data, _) => data.y1,
        sortFieldValueMapper: (ChartData sales, _) => sales.y1,
        color: Color.fromRGBO(51, 102, 255, 1))
  ];
}