You should simply set some interval and zoom chart each time. For example:
private function initialZoom():void
{
var firstDate:Date = dataSet.dataProvider[0].date;
var endDate:Date = new Date(firstDate);
endDate.setDate(endDate.getDate() + 20);
chart.zoom(firstDate, endDate);
setInterval(zoomChart, 1000);
}
private function zoomChart():void
{
var startDate:Date = new Date(chart.startDate);
var endDate:Date = new Date(chart.endDate);
startDate.setDate(startDate.getDate() + 1);
endDate.setDate(endDate.getDate() + 1);
chart.zoom(startDate, endDate);
}
initialZoom should be called on dataUpdated event fired by AmStockChart. Note, you shouldn't set any period as "selected" in order this to work.