Question

我们试图不绘制时间序列jFreeChart中的某些段。

我尝试过这种解决方案，但对我而言，数据集始终为null，因此不确定我在做什么错。 JFreeChart - change SeriesStroke of chart lines from solid to dashed in one line

这是一个带有间隙的图形示例，我们希望不绘制连接线，或者至少要画一条虚线。这是我尝试过的代码：

XYLineAndShapeRenderer minuteRenderer = new XYLineAndShapeRenderer() {
    Stroke solid = new BasicStroke(2.0f);
    @Override
    public Stroke getItemStroke(int row, int column) {
        if (dataset == null) {
            System.out.println("why am I null?");
            return solid;
        }
    }
};

有人可以建议吗？

更新：添加周围的代码以进行说明。注意我确实有一个有效的数据集，因为它正在绘图，但是我拥有的渲染器似乎没有引用它。发生这种类型的覆盖时，也许需要做一些事情来将渲染器链接到数据集？

    // ~~ Plot the Minute Average Data (avg, min, max)
    plot.setDataset(MINUTE_DATA, getMinuteDataset());
    plot.mapDatasetToRangeAxis(MINUTE_DATA, FILL_RANGE_AXIS);
    //XYLineAndShapeRenderer minuteRenderer = new XYLineAndShapeRenderer();
    XYLineAndShapeRenderer minuteRenderer = new XYLineAndShapeRenderer() {
        @Override
        public Paint getItemPaint(int row, int col) {
            System.out.println("get item paint");

            Paint cpaint = getItemColor(row, col);
            if (cpaint == null) {
                cpaint = super.getItemPaint(row, col);
            }
            return cpaint;
        }

        public Color getItemColor(int row, int col) {
            System.out.println(col + "," + dataset.getY(row, col));
            double y = dataset.getYValue(row, col);
            if(y<=3) return Color.black;
            if(y<=4) return Color.green;;
            if(y<=5) return Color.red;;
            if(y<=6) return Color.yellow;;
            if(y<=10) return Color.orange;;
            return null;
        }

        @Override
        protected void drawFirstPassShape(Graphics2D g2, int pass, int series,
            int item, Shape shape) {
            System.out.println("drawing first pass shape");

            g2.setStroke(getItemStroke(series, item));
            Color c1 = getItemColor(series, item);
            Color c2 = getItemColor(series, item - 1);
            GradientPaint linePaint = new GradientPaint(0, 0, c1, 0, 300, c2);
            g2.setPaint(linePaint);
            g2.draw(shape);
        }
    };
    minuteRenderer.setSeriesShapesVisible(0, false);
    minuteRenderer.setSeriesShapesVisible(1, false);
    minuteRenderer.setSeriesShapesVisible(2, false);
    minuteRenderer.setSeriesPaint(0, XBLUE);
    minuteRenderer.setSeriesPaint(1, DODGER_BLUE);
    minuteRenderer.setSeriesPaint(2, DODGER_BLUE);
    plot.setRenderer(MINUTE_DATA, minuteRenderer);

执行上述操作会给我这个空指针错误：

SEVERE: Uncaught exception thrown in java.awt.EventDispatchThread, thread: 14-AWT-EventQueue-0
java.lang.NullPointerException
    at filtec.gui.widgets.fmsqa.FmsLtaChartPanel$1.getItemColor(FmsLtaChartPanel.java:234)

其中数据集为空...

如何在JFreeChart中不绘制时间序列的片段？

0 个答案: