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JFreeChart - 如何将域十字线值转换为 TimeSeriesDataItem

发布于 2025-01-07 07:02:15 字数 218 浏览 3 评论 0原文

我有一个 XYPlot，显示 TimeSeriesCollection 中的多个 TimeSeries。我希望能够获取与域十字准线单击相对应的 TimeSeriesDataItems 列表。

看起来我可以添加一个 PlotChangeListener 来通知十字线值的变化，然后我可以调用 XYPlot.getDomainCrosshairValue()，但我不知道如何使用该十字线值来获取正确的时间序列项

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复古式 2025-01-14 07:02:15

我最终设法弄清楚了。我本来就走在正确的轨道上；添加一个 PlotChangeListener 以接收更改通知，然后获取十字准线值。因为我的域轴是 DateAxis，所以作为十字线值返回的值实际上是十字线所在日期的毫秒值。由此，我可以构造一个 Day 实例，该实例可用于从 TimeSeriesCollection 中的每个 TimeSeries 检索 TimeSeriesDataItem。

plot.addChangeListener(new PlotChangeListener() {

    public void plotChanged(PlotChangeEvent event) {
        double crosshairXValue = this.plot.getDomainCrosshairValue();

        if (crosshairXValue == 0) {
            return;
        }

        Date date = new Date((long) crosshairXValue);
        Day day = new Day(date);

        for (Iterator<TimeSeries> itr = timeseriesCollection.getSeries().iterator(); itr.hasNext(); ) {

            TimeSeries timeSeries = itr.next();
            TimeSeriesDataItem dataItem = timeSeries.getDataItem(day);

            Number balance = dataItem.getValue();

            System.out.println("Balance for day " + day + " is " + balance);
            //TODO publish balances to listeners

        }
    }

});

然后，您还必须向 ChartPanel 添加 MouseClickListener，以便您可以将点击委托给图表。否则你的绘图更改监听器将永远不会被调用。

chartPanel.addChartMouseListener(new ChartMouseListener() {

        public void chartMouseMoved(ChartMouseEvent event) {
            // Do nothing
        }

        public void chartMouseClicked(ChartMouseEvent event) {
            int x = event.getTrigger().getX();
            int y = event.getTrigger().getY();
            chart.handleClick(x, y, chartPanel.getChartRenderingInfo());
        }

    });

I managed to figure it out eventually. I was on the right track originally; add a PlotChangeListener to be notified of a change and then get the crosshair value. Because my domain axis is a DateAxis the value returned as the crosshair value is actually the millisecond value of the date that the crosshair falls on. From that, I can construct a Day instance that can be used to retrieve the TimeSeriesDataItem from each TimeSeries in my TimeSeriesCollection.

plot.addChangeListener(new PlotChangeListener() {

    public void plotChanged(PlotChangeEvent event) {
        double crosshairXValue = this.plot.getDomainCrosshairValue();

        if (crosshairXValue == 0) {
            return;
        }

        Date date = new Date((long) crosshairXValue);
        Day day = new Day(date);

        for (Iterator<TimeSeries> itr = timeseriesCollection.getSeries().iterator(); itr.hasNext(); ) {

            TimeSeries timeSeries = itr.next();
            TimeSeriesDataItem dataItem = timeSeries.getDataItem(day);

            Number balance = dataItem.getValue();

            System.out.println("Balance for day " + day + " is " + balance);
            //TODO publish balances to listeners

        }
    }

});

Then you also have to add a MouseClickListener to the ChartPanel so that you can delegate clicks to the chart. Otherwise your plot change listener will never be invoked.

chartPanel.addChartMouseListener(new ChartMouseListener() {

        public void chartMouseMoved(ChartMouseEvent event) {
            // Do nothing
        }

        public void chartMouseClicked(ChartMouseEvent event) {
            int x = event.getTrigger().getX();
            int y = event.getTrigger().getY();
            chart.handleClick(x, y, chartPanel.getChartRenderingInfo());
        }

    });

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