折线图，一种双轴图表，显示了特定时间间隔内数据的动态。
对于双轴图表，我们可以定义一系列数据XYChart.Series类。
我们可以为每个系列分配一个名称，以便在图例中显示。

  1. import javafx.application.Application;
  2. import javafx.scene.Scene;
  3. import javafx.scene.chart.LineChart;
  4. import javafx.scene.chart.NumberAxis;
  5. import javafx.scene.chart.XYChart;
  6. import javafx.stage.Stage;
  8. public class Main extends Application {
  10.     @Override
  11.     public void start(Stage stage) {
  12.         final NumberAxis xAxis = new NumberAxis();
  13.         final NumberAxis yAxis = new NumberAxis();
  14.         xAxis.setLabel("Number of Month");
  15.         final LineChart<Number, Number> lineChart = new LineChart<Number, Number>(
  16.             xAxis, yAxis);
  18.         lineChart.setTitle("Line Chart");
  19.         XYChart.Series<Number, Number> series = new XYChart.Series<Number, Number>();
  20.         series.setName("My Data");
  21.         // populating the series with data
  22.         series.getData().add(new XYChart.Data<Number, Number>(1, 23));
  23.         series.getData().add(new XYChart.Data<Number, Number>(2, 114));
  24.         series.getData().add(new XYChart.Data<Number, Number>(3, 15));
  25.         series.getData().add(new XYChart.Data<Number, Number>(4, 124));
  27.         Scene scene = new Scene(lineChart, 800, 600);
  28.         lineChart.getData().add(series);
  30.         stage.setScene(scene);
  31.         stage.show();
  32.     }
  34.     public static void main(String[] args) {
  35.         launch(args);
  36.     }
  37. }

image.png

折线图创建

对于每个图表，我们可以设置标题及其相对于图表的位置。标题可以位于图表的顶部，右侧，左侧或底部。
我们可以以相同的方式指定图表图例的位置。

  1. import javafx.application.Application;
  2. import javafx.collections.FXCollections;
  3. import javafx.collections.ObservableList;
  4. import javafx.scene.Scene;
  5. import javafx.scene.chart.CategoryAxis;
  6. import javafx.scene.chart.LineChart;
  7. import javafx.scene.chart.NumberAxis;
  8. import javafx.scene.chart.XYChart;
  9. import javafx.scene.chart.XYChart.Series;
  10. import javafx.scene.layout.StackPane;
  11. import javafx.stage.Stage;
  13. public class Main extends Application {
  14.     public static void main(String[] args) {
  15.         launch(args);
  16.     }
  18.     @Override
  19.     public void start(Stage primaryStage) {
  20.         CategoryAxis xAxis = new CategoryAxis();
  21.         NumberAxis yAxis = new NumberAxis();
  22.         LineChart lineChart = new LineChart(xAxis, yAxis);
  23.         lineChart.setData(getChartData());
  24.         lineChart.setTitle("Chart");
  26.         StackPane root = new StackPane();
  27.         root.getChildren().add(lineChart);
  28.         primaryStage.setScene(new Scene(root, 400, 250));
  29.         primaryStage.show();
  30.     }
  32.     private ObservableList<XYChart.Series<String, Double>> getChartData() {
  33.         double aValue = 10;
  34.         double cValue = 20;
  35.         ObservableList<XYChart.Series<String, Double>> answer = FXCollections
  36.             .observableArrayList();
  37.         Series<String, Double> aSeries = new Series<String, Double>();
  38.         Series<String, Double> cSeries = new Series<String, Double>();
  39.         aSeries.setName("a");
  40.         cSeries.setName("C");
  42.         for (int i = 2001; i < 2021; i++) {
  43.             aSeries.getData().add(new XYChart.Data(Integer.toString(i), aValue));
  44.             aValue = aValue + Math.random()*100 -50;
  45.             cSeries.getData().add(new XYChart.Data(Integer.toString(i), cValue));
  46.             cValue = cValue + Math.random()*100 -50 ;
  47.         }
  48.         answer.addAll(aSeries, cSeries);
  49.         return answer;
  50.     }
  51. }

image.png

折线图的类别

下面的代码显示了如何使用CategoryAxis类而不是NumberAxis类以在线形图中呈现非数字数据。

  1. import javafx.application.Application;
  2. import javafx.scene.Scene;
  3. import javafx.scene.chart.CategoryAxis;
  4. import javafx.scene.chart.LineChart;
  5. import javafx.scene.chart.NumberAxis;
  6. import javafx.scene.chart.XYChart;
  7. import javafx.stage.Stage;
  9. public class Main extends Application {
  11.     @Override
  12.     public void start(Stage stage) {
  13.         final CategoryAxis xAxis = new CategoryAxis();
  14.         final NumberAxis yAxis = new NumberAxis();
  15.         xAxis.setLabel("Month");
  17.         final LineChart<String, Number> lineChart = new LineChart<String, Number>(
  18.             xAxis, yAxis);
  20.         lineChart.setTitle("My Chart");
  22.         XYChart.Series<String, Number> series = new XYChart.Series<String, Number>();
  23.         series.setName("My data");
  25.         series.getData().add(new XYChart.Data<String, Number>("Jan", 23));
  26.         series.getData().add(new XYChart.Data<String, Number>("Feb", 114));
  27.         series.getData().add(new XYChart.Data<String, Number>("Mar", 15));
  28.         series.getData().add(new XYChart.Data<String, Number>("Apr", 24));
  29.         series.getData().add(new XYChart.Data<String, Number>("May", 134));
  31.         Scene scene = new Scene(lineChart, 800, 600);
  32.         lineChart.getData().add(series);
  34.         stage.setScene(scene);
  35.         stage.show();
  36.     }
  38.     public static void main(String[] args) {
  39.         launch(args);
  40.     }
  41. }

image.png

将系列添加到折线图

  1. import java.io.ByteArrayOutputStream;
  3. import java.io.File;
  5. import java.io.IOException;
  9. import javax.imageio.ImageIO;
  11. import javax.imageio.stream.ImageOutputStream;
  15. import javafx.application.Application;
  17. import javafx.embed.swing.SwingFXUtils;
  19. import javafx.scene.Scene;
  21. import javafx.scene.SnapshotParameters;
  23. import javafx.scene.chart.CategoryAxis;
  25. import javafx.scene.chart.LineChart;
  27. import javafx.scene.chart.NumberAxis;
  29. import javafx.scene.chart.XYChart;
  31. import javafx.scene.image.WritableImage;
  33. import javafx.stage.Stage;
  39. public class LineChartSample extends Application {
  43.     @Override 
  45.     public void start(Stage stage) {
  47.         stage.setTitle("Line Chart Sample");
  49.         CategoryAxis xAxis = new CategoryAxis();
  51.         NumberAxis yAxis = new NumberAxis();
  53.         xAxis.setLabel("Month");
  55.         final LineChart<String,Number> lineChart = 
  57.             new LineChart<String,Number>(xAxis,yAxis);
  61.         lineChart.setTitle("Stock Monitoring, 2010");
  65.         XYChart.Series<String,Number> series1 = new XYChart.Series<String,Number>();
  67.         series1.setName("Portfolio 1");
  71.         series1.getData().add(new XYChart.Data<String,Number>("Jan", 23));
  73.         series1.getData().add(new XYChart.Data("Feb", 14));
  75.         series1.getData().add(new XYChart.Data("Mar", 15));
  77.         series1.getData().add(new XYChart.Data("Apr", 24));
  79.         series1.getData().add(new XYChart.Data("May", 34));
  81.         series1.getData().add(new XYChart.Data("Jun", 36));
  83.         series1.getData().add(new XYChart.Data("Jul", 22));
  85.         series1.getData().add(new XYChart.Data("Aug", 45));
  87.         series1.getData().add(new XYChart.Data("Sep", 43));
  89.         series1.getData().add(new XYChart.Data("Oct", 17));
  91.         series1.getData().add(new XYChart.Data("Nov", 29));
  93.         series1.getData().add(new XYChart.Data("Dec", 25));
  97.         XYChart.Series<String,Number> series2 = new XYChart.Series<String,Number>();
  99.         series2.setName("Portfolio 2");
  101.         series2.getData().add(new XYChart.Data("Jan", 33));
  103.         series2.getData().add(new XYChart.Data("Feb", 34));
  105.         series2.getData().add(new XYChart.Data("Mar", 25));
  107.         series2.getData().add(new XYChart.Data("Apr", 44));
  109.         series2.getData().add(new XYChart.Data("May", 39));
  111.         series2.getData().add(new XYChart.Data("Jun", 16));
  113.         series2.getData().add(new XYChart.Data("Jul", 55));
  115.         series2.getData().add(new XYChart.Data("Aug", 54));
  117.         series2.getData().add(new XYChart.Data("Sep", 48));
  119.         series2.getData().add(new XYChart.Data("Oct", 27));
  121.         series2.getData().add(new XYChart.Data("Nov", 37));
  123.         series2.getData().add(new XYChart.Data("Dec", 29));
  127.         XYChart.Series<String,Number> series3 = new XYChart.Series<String,Number>();
  129.         series3.setName("Portfolio 3");
  131.         series3.getData().add(new XYChart.Data("Jan", 44));
  133.         series3.getData().add(new XYChart.Data("Feb", 35));
  135.         series3.getData().add(new XYChart.Data("Mar", 36));
  137.         series3.getData().add(new XYChart.Data("Apr", 33));
  139.         series3.getData().add(new XYChart.Data("May", 31));
  141.         series3.getData().add(new XYChart.Data("Jun", 26));
  143.         series3.getData().add(new XYChart.Data("Jul", 22));
  145.         series3.getData().add(new XYChart.Data("Aug", 25));
  147.         series3.getData().add(new XYChart.Data("Sep", 43));
  149.         series3.getData().add(new XYChart.Data("Oct", 44));
  151.         series3.getData().add(new XYChart.Data("Nov", 45));
  153.         series3.getData().add(new XYChart.Data("Dec", 44));
  155.         Scene scene  = new Scene(lineChart,800,600);       
  157.         lineChart.getData().addAll(series1, series2, series3);
  159.         stage.setScene(scene);
  161.         stage.show();
  163.     }
  165.     public static void main(String[] args) {
  167.         launch(args);
  169.     }
  171. }

image.png