Jfreechart - Refresh a chart according to changing

问题:

I would like to know how to refresh a chart if we want to change "in live" some piece of data. I mean for instance, I have a chart with a TaskSeries which appears on 3 years and I would like to change 3 years by 5 years. I want the chart to change immediately.

Is there some kind of update chart or something like that ?

I know that you could say "get your TaskSeries, do your changes and it will be refreshed automatically" but my TaskSeries are generated and I cannot easily change these ones. That's why I would like to find a way to recalculate and to rebuild the whole chart.

I hope I am enough clear, it's not easy to explain.

Thanks for your help,

Johann

回答1:

The add() method of TaskSeries automatically sends a SeriesChangeEvent to all registered listeners, e.g. CategoryPlot. In this example, DynamicTimeSeriesCollection implements SeriesChangeEvent. In this case, the chart's XYPlot is a registered listener.

回答2:

I had this issue too with an XYPlot. I found a workaround by resetting the dataset:

chart.getXYPlot().setDataset(chart.getXYPlot().getDataset());

that's crazy but it works...

Note: chart.setNotify(true) seems to do nothing.

回答3:

I had this issue; I did it using this:

private void refreshChart() {
    jPanel_GraphicsTop.removeAll();
    jPanel_GraphicsTop.revalidate(); // This removes the old chart 
    aChart = createChart(); 
    aChart.removeLegend(); 
    ChartPanel chartPanel = new ChartPanel(aChart); 
    jPanel_GraphicsTop.setLayout(new BorderLayout()); 
    jPanel_GraphicsTop.add(chartPanel); 
    jPanel_GraphicsTop.repaint(); // This method makes the new chart appear
}

回答4:

I haven't found an easy way to update a JFreeChart "live", since the data-structure of jfreechart is very incompatible to my data-structure. So I build a redraw()-Method of my own, that collects the data from my dataModel, build up a JFreeChart dataModel and set the chart new.

This gives the feeling of a "live" update, also it is very ugly.

回答5:

// create a chart
ChartFrame mychartframe = new ChartFrame("my charts", chart);

// some other stuff ...

// somewhere else in a code far far away
mychartframe.getChartPanel().getChart().fireChartChanged();

回答6:

What worked with me was the following:

//reset with new dataset
chart().setDataset(dataset);
repaint the ChartPanel that contains the JFreeChart
chartPanel.repaint();