Question

我想在条形图中画一条线。该行反映了与其他值进行比较的特定值。我将solution for a LineChart应用于我的情况（参见代码）。但是，没有画线。

 public XYChart buildBarChart ()
   {
      Line valueMarker = new Line ();
      CategoryAxis xAxis = new CategoryAxis();
      NumberAxis yAxis = new NumberAxis();
      BarChart<String,Number> barChart = new BarChart<String,Number> (xAxis,yAxis);
      barChart.setBarGap (-10);
      barChart.setCategoryGap (0);
      barChart.getYAxis().setTickLabelsVisible(false);
      barChart.getYAxis().setOpacity(0);      
      yAxis.setLabel ("Score");

      // update marker
      Node chartArea = barChart.lookup (".chart-plot-background");
      Bounds chartAreaBounds = chartArea.localToScene (chartArea.getBoundsInLocal ());

      // remember scene position of chart area
      yShift = chartAreaBounds.getMinY();

      // set x parameters of the valueMarker to chart area bounds
      valueMarker.setStartX (chartAreaBounds.getMinX());
      valueMarker.setEndX (chartAreaBounds.getMaxX());

      // find pixel position of that value
      double displayPosition = yAxis.getDisplayPosition (valNederland);

      // update marker
      valueMarker.setStartY (yShift + displayPosition);
      valueMarker.setEndY (yShift + displayPosition);

      BarChart.Series<String,Number> series1 = new BarChart.Series<String,Number> ();
      BarChart.Series<String,Number> series2 = new BarChart.Series<String,Number> ();
      BarChart.Series<String,Number> series3 = new BarChart.Series<String,Number> ();
      BarChart.Series<String,Number> series4 = new BarChart.Series<String,Number> ();

      series1.getData ().add (new XYChart.Data<String,Number> (sRegio, valRegio_2015));
      series2.getData ().add (new XYChart.Data<String,Number> (sOmgeving, valOmgeving));
      series3.getData ().add (new XYChart.Data<String,Number> (sRest, valRest));
      series4.getData ().add (new XYChart.Data<String,Number> (sNl, valNederland));
      barChart.getData().addAll (series1, series2, series3, series4);

      return barChart;
   } /*** buildBarChart ***/

这种情况必不可少的是拥有ChartArea的坐标。当我在调试器中检查ChartArea的属性时，我发现_geomBounds的所有值都是＆＃39; unlogic＆＃39;，即maxX / Y = -1和minX / Y = -1。在为chartASreaBounds分配值后，我只检查一行。

对我来说，似乎barChart查找失败，因为之前我遇到过类似的问题。有没有人建议如何纠正这种情况？

修改

BarChart在构造函数中创建如下：

 public Charter (int nTimes, int nCategories, float [] years, String [] titles, String label, Indicator ind, float [] past)
   {
      this ();

      // all kind of code to do somethong with the parameters omitted
      // ...

      // Setting up the BarChart. Note that past == null in my experiments
      HBox hBox = new HBox ();
      XYChart bar = buildBarChart ();
      bar.setPrefHeight (height);
      bar.setPrefWidth (width);

      VBox buttons = buildButtonView ();

      if (past != null)
      {
         XYChart line = buildLineChart ();
         line.setPrefHeight (height);
         line.setPrefWidth (width);
         hBox.getChildren ().addAll (bar, line);
      } else
      {
         hBox.getChildren ().addAll (bar);
      } // if
      Label dsecription = new Label (label);
      this.getProperties ().put ("--Indicator", ind.getName ());
      this.getChildren ().addAll (dsecription, hBox);
   } /*** Charter ***/

创建宪章后，它会被添加到VBox中，并随着VBox已添加到场景中而显示在屏幕上。

Answer 1

看起来您想在将条形图添加到场景之前计算条形图在屏幕上的位置。从那时起，屏幕上还没有位置为-1或未定义。

我倾向于在fxml中制作我的布局，因此不会出现这样的问题。如果您需要在代码中执行此操作，我认为首先将其添加到hBox的子项中，然后绘制该行可以解决问题。

JavaFX无法在BarChart中绘制线条

1 个答案: