public void setOnValueTouchListener(ColumnChartOnValueSelectListener touchListener) {
        if (null != touchListener) {
            this.onValueTouchListener = touchListener;
        }
    }
ColumnChart/BarChart, supports subcolumns, stacked collumns and negative values.

@author Leszek Wach
hellocharts-library/src/lecho/lib/hellocharts/view/ColumnChartView.java