我可以访问谷歌图表生成的值吗

Question

目前我将变量传递给 api，如下所示：

<script type="text/javascript">
 mobileNav();
 // Load the Visualization API and the piechart package.
 google.load('visualization', '1.0', {'packages':['corechart']});

 // Set a callback to run when the Google Visualization API is loaded.
 google.setOnLoadCallback(drawChart);

 //Callback that creates and populates a data table,
 // instantiates the pie chart, passes in the data and
 // draws it.
 function drawChart() {

  // Create the data table.
  var data = new google.visualization.DataTable();
  data.addColumn('string', 'Date');
  data.addColumn('number', 'Attendance');
  data.addRows([
    ['Present', <?php echo $present; ?>],
    ['Absent', <?php echo $absent; ?>],
    ['Directed Study', <?php echo $directed; ?>],
    ['Medical Certificate', <?php echo $medical; ?>],
    ['Self Certificate', <?php echo $selfcert; ?>],
    ['Authorised Absence', <?php echo $authorised; ?>],
  ]);

  // Set chart options
  var options = {'title':'Your Attendance'};


  // Instantiate and draw our chart, passing in some options.
  var chart = new      google.visualization.PieChart(document.getElementById('chart_div'));
  chart.draw(data, options);

我得到了结果，一切都很好。我想访问饼图生成的 % 值。有什么办法可以实现吗？

Answer 1

如果您想访问饼图生成的值，则需要在 dataTable() 上检索数据。

您需要使用 getFormattedValue 方法。

文档： 数据表 API：https://developers.google.com/chart/interactive/docs/reference#DataTable

方法：getFormattedValue(rowIndex, columnIndex)