Question

我在javafx8中使用LineChart，我能够在图表中动态绘制系列，并为每个输入绘制符号。但问题是我只想显示当前节点的符号，而不是已经添加的节点。

我试过了：

linechart.setCreateSymbols(false);

但这并不符合我的需要。它停止为输入创建符号。

任何人都可以告诉如何仅显示当前符号而不是添加的oness ????

Answer 1

只需跟踪添加的最后一个数据点的节点。添加新点时，将前一个“最后一个点”的可见性设置为false。

您可以直接使用

执行此操作

import java.util.Random;

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart.Data;
import javafx.scene.chart.XYChart.Series;
import javafx.scene.control.Button;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class LineChartShowSymbolForLastPointOnly extends Application {

    private Node lastPointAdded ;

    @Override
    public void start(Stage primaryStage) {
        LineChart<Number, Number> chart = new LineChart<>(new NumberAxis(), new NumberAxis());
        Series<Number, Number> series = new Series<>();
        chart.getData().add(series);
        chart.setAnimated(false);

        Button addDataPointButton = new Button("Add data point");
        Random rng = new Random();
        addDataPointButton.setOnAction(e -> {
            if (lastPointAdded != null) {
                lastPointAdded.setVisible(false);
            }
            Data<Number, Number> data = new Data<>(series.getData().size(), rng.nextDouble());
            series.getData().add(data);
            lastPointAdded = data.getNode();
        });

        BorderPane.setAlignment(addDataPointButton, Pos.CENTER);
        BorderPane.setMargin(addDataPointButton, new Insets(10));
        BorderPane root = new BorderPane(chart, null, null, addDataPointButton, null);

        primaryStage.setScene(new Scene(root, 800, 600));
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

如果您希望能够更容易地将代码分解出来，可以使用ObjectProperty并注册一个监听器：

import java.util.Random;

import javafx.application.Application;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.chart.LineChart;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart.Data;
import javafx.scene.chart.XYChart.Series;
import javafx.scene.control.Button;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class LineChartShowSymbolForLastPointOnly extends Application {

    @Override
    public void start(Stage primaryStage) {
        LineChart<Number, Number> chart = new LineChart<>(new NumberAxis(), new NumberAxis());
        Series<Number, Number> series = new Series<>();
        chart.getData().add(series);
        chart.setAnimated(false);


        ObjectProperty<Node> lastPointAdded = new SimpleObjectProperty<>();
        lastPointAdded.addListener((obs, oldNode, newNode) -> {
            if (oldNode != null) {
                oldNode.setVisible(false);
            }
        });

        Button addDataPointButton = new Button("Add data point");
        Random rng = new Random();
        addDataPointButton.setOnAction(e -> {
            Data<Number, Number> data = new Data<>(series.getData().size(), rng.nextDouble());
            series.getData().add(data);
            lastPointAdded.set(data.getNode());
        });

        BorderPane.setAlignment(addDataPointButton, Pos.CENTER);
        BorderPane.setMargin(addDataPointButton, new Insets(10));
        BorderPane root = new BorderPane(chart, null, null, addDataPointButton, null);

        Scene scene = new Scene(root, 800, 600);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }
}

当前节点+ LineChart + JavaFX

1 个答案: