XYPointerAnnotation in TimeSeries JFreeChart

问题:

I'm trying to implement XYPointerAnnotation to TimeSeries chart. However I don't know, how does chart finds my y values to plot. Code:

final TimeSeries series = new TimeSeries("asdfas"); Hour hour = new Hour(); series.add(2,hour), 123); TimeSeriesCollection collection = new TimeSeriesCollection(); collection.addSeries(series); double temp = Double.parseDouble(     series1.getTimePeriod(series1.getItemCount()-1).toString()); XYPointerAnnotation pointer1 = new XYPointerAnnotation(     series1.getValue(series1.getItemCount() - 1).toString(), temp, 00.0); JFreeChart chart = ChartFactory.createTimeSeriesChart(     "1", "2", "3", collection, true, true, false); 

How can I parse y values from TimeSeries to the XYPointerAnnotation?

回答1:

Given a TimeSeries,

TimeSeries series = new TimeSeries("Data"); 

find the item of interest,

TimeSeriesDataItem item = series.getDataItem(series.getItemCount() - 1); 

create an annotation based on the period and value,

double x = item.getPeriod().getFirstMillisecond(); double y = item.getValue().doubleValue(); XYPointerAnnotation a = new XYPointerAnnotation("Bam!", x, y, 5 * Math.PI / 8); 

and add it to the plot,

XYPlot plot = (XYPlot) chart.getPlot(); plot.addAnnotation(a); 

文章来源: XYPointerAnnotation in TimeSeries JFreeChart