private void toggleLabelForSelected() {
            hasLabelForSelected = !hasLabelForSelected;

            chart.setValueSelectionEnabled(hasLabelForSelected);

            if (hasLabelForSelected) {
                hasLabels = false;
            }

            generateData();
        }
Adds lines to data, after that data should be set again with
{@link LineChartView#setLineChartData(LineChartData)}. Last 4th line has non-monotonically x values.
hellocharts-samples/src/lecho/lib/hellocharts/samples/LineChartActivity.java