无法识别立即选择 google 饼图的同一切片

Question

我试图在选择 google 饼图的特定切片时显示具有特定信息的模态。当一个接一个地选择不同的切片时代码工作正常，但是当第二次连续选择相同的切片时没有触发事件。

google.visualization.events.addListener(chart, 'select', selectHandler);
function selectHandler()
                    {
                        var selectedItem = chart.getSelection()[0];
                        if (selectedItem)
                        {
                            alert("here");
                        }
                    }

Answer 1

事件被触发，但第二次点击切片时，它未被选中。

您应该在尝试访问之前检查所选内容的长度 --> [0]

参见以下示例...

google.charts.load('current', {
  callback: function () {
    var data = google.visualization.arrayToDataTable([
      ['Task', 'Hours per Day'],
      ['Work',     12],
      ['Eat',       2],
      ['Drink',     1],
      ['Commute',   1],
      ['Surf',      1],
      ['Watch TV',  1],
      ['Sleep',     6]
    ]);

    var pieChart = new google.visualization.PieChart(document.getElementById('piechart'));
    google.visualization.events.addListener(pieChart, 'select', function () {
      document.getElementById('selection').innerHTML = 'Items selected: ' + pieChart.getSelection().length;
    });
    pieChart.draw(data, {});
  },
  packages: ['corechart']
});

<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="piechart"></div>
<div id="selection"></div>

无法识别立即选择 google 饼图的同一切片

Immediate selection of same slice of google pie chart not recognised

javascript

charts

google-visualization

pie-chart