You need to enable JavaScript to run this app.
优惠活动
大模型
产品
解决方案
定价
更多

JavaFX ScheduledService的updateMessage未按预期更新问题求助

问题描述

开发的JavaFX应用整体运行正常,但ScheduledService的updateMessage方法出现异常行为。原本预期每次调用updateMessage都会更新messageProperty(每5秒执行一次),但实际并未生效,而updateValue和System.out.println均能正常工作。需要确认这是组件故障还是对updateMessage的理解存在偏差。


代码实现

Main类

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.concurrent.ScheduledService;
import javafx.concurrent.Task;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.VBox;
import javafx.util.Duration;
import org.controlsfx.control.Notifications;

public class App extends Application {
    
    static List<MyNotification> myNotifications = new ArrayList();
    static FakeDatabaseHandler fakeDatabaseHandler = new FakeDatabaseHandler();
    
    @Override
    public void start(Stage stage) {
        
        Button btnGenerateNotification = new Button("Generate!");
        btnGenerateNotification.setOnAction(actionEvent ->{            
             fakeDatabaseHandler.addFakeNotificationsToDb();
        });

        Label lblUpdateMessage = new Label("Update Message: ");
        
        ScheduledService<List<MyNotification>> checkForScheduledService = new CheckForNotificationsScheduledService();
        checkForScheduledService.setPeriod(Duration.seconds(5));
        checkForScheduledService.messageProperty().addListener((ov, oldValue, newValue) -> {
            if(newValue != null)
            {
                lblUpdateMessage.setText("Update Message: " + newValue);
            }
        });
        
        checkForScheduledService.valueProperty().addListener((ov, oldValue, newValue) -> {
            if(newValue != null && !newValue.isEmpty())
            {
                myNotifications.clear();
                myNotifications.addAll(newValue);
                checkForScheduledService.cancel();
                
                AtomicInteger index = new AtomicInteger(0);
                checkForScheduledService.cancel();
                Timeline threeSecondsWonder = new Timeline(
                    new KeyFrame(Duration.seconds(3),  event -> {    
                        MyNotification myNotification = myNotifications.get(index.getAndIncrement());
                        Notifications.create().title(myNotification.department()+ " - " + myNotification.title()).text(myNotification.message()).hideAfter(Duration.seconds(3)).showWarning();
                    })
                );
                threeSecondsWonder.setCycleCount(myNotifications.size());
                threeSecondsWonder.play();
                threeSecondsWonder.setOnFinished((t) -> {
                    checkForScheduledService.restart();
                });
            }
        });
        checkForScheduledService.start();
        
        StackPane root = new StackPane(new VBox(btnGenerateNotification, lblUpdateMessage));

        stage.setScene(new Scene(root, 500, 500));
        stage.setTitle("Facilities");
        stage.show();        
    }

    public static void main(String[] args) {
        launch(args);
    }
    
    private static class CheckForNotificationsScheduledService extends ScheduledService<List<MyNotification>> {

    @Override
    protected Task<List<MyNotification>> createTask() {
        return new Task<List<MyNotification>>() {
            @Override
            protected List<MyNotification> call() throws Exception {
                List<MyNotification> fakeNotificationList = fakeDatabaseHandler.getFakeNotificationsFromDB();
                
                System.out.println("Checking for notifications. Notifications Found: " + fakeNotificationList.size());
                updateMessage("Checking for notifications. Notifications Found: " + fakeNotificationList.size());             
                updateValue(fakeNotificationList);                
                
                return fakeNotificationList; 
            }
        };
    }
  }
}

FakeDatabaseHandler类

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.ThreadLocalRandom;

/**
 *
 * @author Sed
 */
public class FakeDatabaseHandler {
    private final List<MyNotification> fakeDBData = new ArrayList();    
    
    public FakeDatabaseHandler() {}
    
    public void addFakeNotificationsToDb(){
        List<String> departmentList = Arrays.asList("A", "B", "C", "D");
              
        for(int i = 0; i < ThreadLocalRandom.current().nextInt(1, 6); i++)
        {
            int notificationID = ThreadLocalRandom.current().nextInt( 1000000);
            fakeDBData.add(new MyNotification("Department: " + departmentList.get(ThreadLocalRandom.current().nextInt(4)), "Title " + notificationID, "Message: " + notificationID));
        }
    }
    
    public List<MyNotification> getFakeNotificationsFromDB(){
        List<MyNotification> returnList = new ArrayList(fakeDBData);
        fakeDBData.clear();
        
        return returnList;
    }
}

MyNotification记录类

public record MyNotification(String department, String title, String message) {}

Module-Info

module com.mycompany.javafxsimpletest {  
    requires org.controlsfx.controls;
    exports com.mycompany.javafxsimpletest;
}

输出效果

输出效果展示


技术信息
Product Version: Apache NetBeans IDE 18
Java: 19.0.2; OpenJDK 64-Bit Server VM 19.0.2+7-jvmci-22.3-b12
Runtime: OpenJDK Runtime Environment 19.0.2+7-jvmci-22.3-b12
System: Windows 11 version 10.0 running on amd64; UTF-8; en_US (nb)

内容的提问来源于stack exchange,提问作者SedJ601

相关产品推荐
方舟 Agent Plan

超全模态模型 × Harness 升级,最新支持 Deepseek-V4.1-Flash、GLM-5.3 系列、Doubao-Seedream-5.0-pro、Kimi-K3 (部分), 限时 9.9 元起

最近更新时间:2026.07.11 03:35:56