Callbacks in Syncfusion Flutter charts

Callbacks in Pyramid Charts

The below Callbacks are for Pyramid chart.

onLegendItemRender

Triggers when the legend item is rendering. Here, you can customize the legend’s text, and shape. The onLegendItemRender Callback contains the following arguments.

• text - specifies the content of the legend.
• pointIndex - specifies the current point index that is applicable for Pyramid chart type alone.
• seriesIndex - specifies the current series index.
• legendIconType - specifies the shape of the legend.

dart

@override
    Widget build(BuildContext context) {
    
    return Scaffold(
      body: Center(
        child: SfPyramidChart(
          legend: Legend(isVisible: true),
          onLegendItemRender: (LegendRenderArgs args){
            args.text = 'Legend Text';
            args.legendIconType = LegendIconType.diamond;
          }
        )
      )
    );
  }

onTooltipRender

Triggers while tooltip is rendering. Here, you can customize the text, header, x and y-positions. The onTooltipRender Callback contains the following arguments.

• text - specifies the content of the tooltip.
• header - specifies the header content of the tooltip.
• locationX - specifies the x position of tooltip.
• locationY - specifies the y position of tooltip.
• seriesIndex - specifies the current series index.
• dataPoints - holds the data point collection.
• pointIndex - specifies the current point index.

dart

@override
    Widget build(BuildContext context) {
    
    return Scaffold(
      body: Center(
        child: SfPyramidChart(
          onTooltipRender: (TooltipArgs args){
            args.text = 'Custom Text';
          },
          tooltipBehavior: TooltipBehavior(enable: true),
        )
      )
    );
  }

onDataLabelRender

Triggers when data label is rendering. Text and text styles such as color, font size, and font weight can be customized. The onDataLabelRender Callback contains the following arguments.

• text - specifies the content of the data label.
• textStyle – used to change the text color, size, font family, font style, and font weight.
• pointIndex - specifies the current point index.
• series - specifies current series.

dart

@override
    Widget build(BuildContext context) {
    
    return Scaffold(
      body: Center(
        child: SfPyramidChart(
          onDataLabelRender:(DataLabelRenderArgs args){
            args.text = 'Data label';
          },
          series: PyramidSeries<ChartData, String>(
             dataLabelSettings: DataLabelSettings(
                isVisible: true
             )
            )
        )
      )
    );
  }

onLegendTapped

Triggers when tapping the legend item. The onLegendTapped Callback contains the following arguments.

• seriesIndex - specifies the current series index.
• pointIndex - specifies the current point index that is applicable for Pyramid series.
• series - specifies the current series.

dart

@override
    Widget build(BuildContext context) {
    
    return Scaffold(
      body: Center(
        child: SfPyramidChart(
          onLegendTapped: (LegendTapArgs args) {
            print(args.seriesIndex);
          },
          legend: Legend(isVisible: true)
      )
    );
  }

onSelectionChanged

Triggers while selection changes. Here you can customize the selectedColor, unselectedColor, selectedBorderColor, selectedBorderWidth, unselectedBorderColor, and unselectedBorderWidth properties. The onSelectionChanged Callback contains the following arguments.

• series - specifies current series.
• seriesIndex - specifies the current series index.
• pointIndex - specifies the current point index.
• selectedColor - specifies color of the selected data points or series.
• unselectedColor - specifies color of the unselected data points or series.
• selectedBorderColor - specifies border color of the selected data points or series.
• selectedBorderWidth - specifies border width of the selected data points or series.
• unselectedBorderColor - specifies border color of the unselected data points or series.
• unselectedBorderWidth - specifies border width of the unselected data points or series.

dart

@override
    Widget build(BuildContext context) {
    
    return Scaffold(
      body: Center(
        child: SfPyramidChart(
         onSelectionChanged: (SelectionArgs args){
            args.selectedColor = Colors.red;
            args.unselectedColor = Colors.lightGreen;
          },
          series: PyramidSeries<ChartData, String>(
              selectionSettings: SelectionSettings(
                enable: true
              )
            )
        )
      );
    }