在您的BuildData
(顺便说一下,不遵循 Java 命名约定,更改其名称)方法中,您正在更新系列的数据。以同样的方法将此系列添加到图表中。通过单击“下一步”按钮,BuildData
将调用再次添加此图表的方法,这是不必要的。删除
Platform.runLater(() -> {
barchart.getData().add(series1);
});
该方法的一部分并在开始时仅添加一次图表:
...
...
vbox.getChildren().addAll(box, barchart);
barchart.getData().add(series1);
pane.getChildren().add(vbox);
...
...
经测试的 SSCCE:
import java.util.Calendar;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.geometry.Insets;
import javafx.geometry.Orientation;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.chart.BarChart;
import javafx.scene.chart.CategoryAxis;
import javafx.scene.chart.NumberAxis;
import javafx.scene.chart.XYChart;
import javafx.scene.control.Button;
import javafx.scene.layout.FlowPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
public class BarChartDemo extends Application {
final String[] months = {"Janvier", "Février", "Mars", "Avril", "Mai", "Juin", "Juillet", "Août", "Septembre", "Octobre", "Novembre", "Décembre"};
//Connection conn;
final CategoryAxis month_axis = new CategoryAxis();
final NumberAxis data_axis = new NumberAxis();
final XYChart.Series<String, Number> series1 = new XYChart.Series();
private final BarChart<String, Number> barchart = new BarChart(month_axis, data_axis);
private Integer year = 0;
@Override
public void start(Stage primaryStage) {
year = Calendar.getInstance().get(Calendar.YEAR);
Button btn_next = new Button("NEXT");
Button btn_previous = new Button("PREVIOUS");
HBox box = new HBox(50);
box.getChildren().addAll(btn_previous, btn_next);
box.setAlignment(Pos.TOP_CENTER);
VBox vbox = new VBox(25);
box.setPadding(new Insets(10, 0, 10, 0));
FlowPane pane = new FlowPane(Orientation.VERTICAL);
vbox.getChildren().addAll(box, barchart);
barchart.getData().add(series1);
pane.getChildren().add(vbox);
Scene scene = new Scene(pane);
primaryStage.setTitle("Hello World!");
primaryStage.setScene(scene);
primaryStage.show();
BuildData(year);
btn_next.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
year += 1;
BuildData(year);
}
});
btn_previous.setOnAction(new EventHandler<ActionEvent>() {
@Override
public void handle(ActionEvent event) {
year -= 1;
BuildData(year);
}
});
}
public static void main(String[] args) {
launch(args);
}
private void BuildData(Integer y) {
series1.setName("Versement");
month_axis.setLabel("Mois de l'Année");
month_axis.setStyle("-fx-font-weight:BOLD;" + "-fx-font-size:15");
data_axis.setLabel("Valeur des Opérations Bancaires");
data_axis.setStyle("-fx-font-weight:BOLD;" + "-fx-font-size:15");
series1.getData().clear(); // clear old values
for (int i = 0; i < months.length; i++) {
series1.getData().add(new XYChart.Data(months[i], i * 10 * (y-2000)));
// try {
// String a;
// if (i < 9) {
// a = y + "0" + (i + 1);
// } else {
// a = y + "" + (i + 1);
// }
// conn = DBConnection.connect();
// String sql = "select sum(montant_operation) from operations where (select Extract(YEAR_MONTH from date_operation)) = '" + a + "' and typ_operation ='Versement';";
// final ResultSet rs = conn.prepareStatement(sql).executeQuery();
// if (rs.next()) {
// series1.getData().add(new XYChart.Data<>(months[i], rs.getFloat("sum(montant_operation)")));
// }
// } catch (SQLException e) {
// System.out.println(e);
// }
}
}
}