javascript - 如何在 Chart.js v2.0 中的标签上添加 OnClick 事件？

Question

寻找一种在 chartjs 2.0 中的“label”元素上添加 onClick 句柄的方法使用下面的方法，每当点击 Char.js V2.0 RadarChart 中的任何一个标签属性时，都会在 console.log 中返回“undifined”。

var data = {
    // below line is the labels 
    labels: ["Eating", "Drinking", "Sleeping", "Designing", "Coding", "Cycling", "Running"],
    datasets: [
        {
            label: "My First dataset", //this only shows as legend, not label.

            backgroundColor: "rgba(179,181,198,0.2)",
            borderColor: "rgba(179,181,198,1)",
            pointBackgroundColor: "rgba(179,181,198,1)",
            pointBorderColor: "#fff",
            pointHoverBackgroundColor: "#fff",
            pointHoverBorderColor: "rgba(179,181,198,1)",
            data: [65, 59, 90, 81, 56, 55, 40]
        },
       ....

//Below is how to OnClick on chart points in chart.js V2, 
//However, it didn't apply to labels, will return "undifined" .   
$('#ChartV2').click(function(e) {
                var activePoints = myRadarChart.getElementsAtEvent(e);                  
                var firstPoint = activePoints[0];
                console.log(firstPoint);
                if (firstPoint !== undefined){
                   alert(firstPoint._index);                        
                }
 });

Answer 1

在 chart.js 2.5(甚至更早)中，您可以在选项中放置一个 onClick:

'legend' : {
    'onClick' : function (evt, item) {
                    console.log ('legend onClick', evt, item);
                },
    'display' : true,
    'labels' : ...