如何知道在amcharts中堆积的条形图上单击了哪个类别？

Question

我有一个堆积的条形图，并在其上分配了一个单击侦听器，以了解单击了哪个项目。

series.columns.template.events.on("hit", function(ev) {
    console.log(ev.target);
}, this);

但是在相应的target.dataItem json中，我找不到单击类别的任何字段。仅年份和数值可用。如何获得实际的图例类别？Codepen implementation

Answer 1

您可以通过target.dataItem.component访问系列信息。这将包含用于填充图例的系列信息，例如名称。

series.columns.template.events.on("hit", function(ev) {
    console.log(ev.target.dataItem.component.name);
}, this);

下面的演示：

// Themes begin
am4core.useTheme(am4themes_animated);
// Themes end

// Create chart instance
var chart = am4core.create("chartdiv", am4charts.XYChart);

// Add data
chart.data = [{
  "year": "2016",
  "europe": 2.5,
  "namerica": 2.5,
  "asia": 2.1,
  "lamerica": 0.3,
  "meast": 0.2,
  "africa": 0.1
}, {
  "year": "2017",
  "europe": 2.6,
  "namerica": 2.7,
  "asia": 2.2,
  "lamerica": 0.3,
  "meast": 0.3,
  "africa": 0.1
}, {
  "year": "2018",
  "europe": 2.8,
  "namerica": 2.9,
  "asia": 2.4,
  "lamerica": 0.3,
  "meast": 0.3,
  "africa": 0.1
}];

chart.legend = new am4charts.Legend();
chart.legend.position = "right";

// Create axes
var categoryAxis = chart.yAxes.push(new am4charts.CategoryAxis());
categoryAxis.dataFields.category = "year";
categoryAxis.renderer.grid.template.opacity = 0;

var valueAxis = chart.xAxes.push(new am4charts.ValueAxis());
valueAxis.min = 0;
valueAxis.renderer.grid.template.opacity = 0;
valueAxis.renderer.ticks.template.strokeOpacity = 0.5;
valueAxis.renderer.ticks.template.stroke = am4core.color("#495C43");
valueAxis.renderer.ticks.template.length = 10;
valueAxis.renderer.line.strokeOpacity = 0.5;
valueAxis.renderer.baseGrid.disabled = true;
valueAxis.renderer.minGridDistance = 40;

// Create series
function createSeries(field, name) {
  var series = chart.series.push(new am4charts.ColumnSeries());
  series.dataFields.valueX = field;
  series.dataFields.categoryY = "year";
  series.stacked = true;
  series.name = name;
  
  var labelBullet = series.bullets.push(new am4charts.LabelBullet());
  labelBullet.locationX = 0.5;
  labelBullet.label.text = "{valueX}";
  labelBullet.label.fill = am4core.color("#fff");
  
   series.columns.template.events.on("hit", function(ev) {
        console.log(ev.target.dataItem.component.name);
    }, this);
}

createSeries("europe", "Europe");
createSeries("namerica", "North America");
createSeries("asia", "Asia");
createSeries("lamerica", "Latin America");
createSeries("meast", "Middle East");
createSeries("africa", "Africa");

#chartdiv {
  width: 100%;
  height: 500px;
}

<script src="https://www.amcharts.com/lib/4/core.js"></script>
<script src="https://www.amcharts.com/lib/4/charts.js"></script>
<script src="https://www.amcharts.com/lib/4/themes/animated.js"></script>
<div id="chartdiv"></div>