Re: How to get the data of a selected point with chart range filter.

[asgallant]

There are two things you can do, which you use depends on what you want to do with the data.  If you just need to access the data, then call the #getDataTable method of the chartWrapper and use the row reference in that.  If you need to manipulate the data (or have another reason why you need to work in the base DataTable), then you call the #getDataTable method, and then use the #getTableRowIndex method of the object returned to get the row index in the base DataTable.

Method 1:

google.visualization.events.addListener(chart, 'select', function () {
    var selection = chart.getSelection();
    var tmpData = chart.getDataTable();
    alert(tmpData.getValue(selection[0].row, selection[0].column));
});

Method 2:

google.visualization.events.addListener(chart, 'select', function () {
    var selection = chart.getSelection();
    var tmpData = chart.getDataTable();
    var baseRowIndex = tmpData.getTableRowIndex(selection[0].row);
    var baseColumnIndex = tmpData.getTableColumnIndex(selection[0].column);
    alert(data.getValue(baseRowIndex, baseColumnIndex));
}); 

On Thursday, August 30, 2012 11:59:51 AM UTC-4, abacus wrote:

Hi, I am using a control wrapper of type ChartRangeFilter with a LineChart and I am having problems accessing the row a user has selected.

When I use the getSelection method on the chart it returns a row corresponding to what is currently displayed on the chart. (So if the range is set to start at the 30th point and the user selects the first possible item the row number would still be 0, where as I would be wanting the value 30). I need to calculate the actual row number in order to know which item of data the user has actually clicked on. The simplest way would be to use getState().range.start on the control wrapper, but this is out of sync with the actual chart. This is because getState() gives you the row equal to or before the current filter position, where as the chart displays the row equal to or after the current filter position. 

I can provide screenshots if you don't understand what I mean by the chart and the control being out of sync. 

How can I get to the selected data no matter what filter is put on the chart? The only other idea I have is to use the toJSON method on the chart wrapper and parse that, but that seems like a nasty solution.

[abacus]

Awesome thanks, that works like a treat.

[Da Ka]

This just saved me a lot of time! Works like a charm, thanks!