How to change tooltip text for google chart api?

Question

http://code.google.com/apis/chart/

<script type="text/javascript" src="https://www.google.com/jsapi"></script>
<script type="text/javascript">

  // Load the Visualization API and the piechart package.
  google.load('visualization', '1', {'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 our data table.
  var data = new google.visualization.DataTable();
  data.addColumn('string', 'date');
  data.addColumn('number', 'Views');
  data.addColumn('number', 'People');
  data.addRows([
    <?php echo $analytics; ?>
  ]);
  // Instantiate and draw our chart, passing in some options.
  var chart = new google.visualization.AreaChart(document.getElementById('Analytics-Visualization'));
  chart.draw(data, {lineWidth:3, pointSize:8, width: 745, height: 240,chartArea:{left:20,top:20,width:640}});
}
</script>

lets say when we do this it does this

to

maybe using the listener stuff ?

Answer 1

For custom tooltips, add the tooltip as an extra column:

function drawVisualization() {
    data = new google.visualization.DataTable()
    data.addColumn('string', 'Date');
    data.addColumn('number');
    data.addColumn({type:'string',role:'tooltip'});
    data.addRow();
    base = 10;
    data.setValue(0, 0, 'Datapoint1');
    data.setValue(0, 1, base++);
    data.setValue(0, 2, " This is my tooltip1 ");

    data.addRow();
    data.setValue(1, 0, 'Datapoint2');
    data.setValue(1, 1, base++);
    data.setValue(1, 2, "This is my second tooltip2");

    // Draw the chart.
    var chart = new google.visualization.BarChart(document.getElementById('visualization'));
    chart.draw(data, {legend:'none', width:600, height:400});
}