Myujth

Im trying to build a Quizz Application with JavaFX.
The user is supposed to answer as many questions as possible in one minute. I have created a subclass of BarChart that i want to use to visualise the how much time is left. My class implements Runnable because the timer is supposed to run as its own thread (right?).

I want to set the bargraph to 60, and then decrease the bar for each second. I have tried different ways to do this but none of them are succesful.

Heres what the class look like now:

public class StopWatchBar extends BarChart implements Runnable 

public StopWatchBar() 

super(new CategoryAxis(), new NumberAxis(0, 60, 1));

 super.setTitle("Time");
 this.setMaxWidth(200);
 this.setScaleShape(true);
 this.setAnimated(false);
 this.setCenterShape(true);


@Override
public void run() 

 XYChart.Series timeDataSeries = new XYChart.Series();
 timeDataSeries.getData().add(new XYChart.Data<String, Integer>("", 60));
 this.getData().add(timeDataSeries);

 int counterSeconds = 60;
 long startTime = System.currentTimeMillis();
 long endTime = System.currentTimeMillis() + (counterSeconds * 1000);
 long startTimePlusOneSecond = startTime + 1000;

 while (startTime < endTime) 
 if (startTime == startTimePlusOneSecond) 
 timeDataSeries.getData().clear();
 timeDataSeries.getData().add(new XYChart.Data<String, Number>("", counterSeconds));
 counterSeconds--;
 startTimePlusOneSecond += 1000;
 
 startTime = System.currentTimeMillis();
 

I have created an object of the class as an instance object in my Scene in PrimaryStage.
In the same scene i also have a button that i want to use to test to execute the counter:
Like this:

timerTestButton.setOnAction(actionEvent -> 
 Thread timeBarRunner = new Thread(timeBar);
 timeBarRunner.start();
 );

When i push the button in the UI i get the Exception:

Exception in thread "Thread-4" java.lang.IllegalStateException: Not on FX application thread; currentThread = Thread-4
at com.sun.javafx.tk.Toolkit.checkFxUserThread(Toolkit.java:279)
at com.sun.javafx.tk.quantum.QuantumToolkit.checkFxUserThread(QuantumToolkit.java:423)
at javafx.scene.Parent$2.onProposedChange(Parent.java:367)
at com.sun.javafx.collections.VetoableListDecorator.add(VetoableListDecorator.java:206)
at javafx.scene.chart.BarChart.seriesAdded(BarChart.java:293)
at javafx.scene.chart.XYChart.lambda$new$550(XYChart.java:160)
at com.sun.javafx.collections.ListListenerHelper$SingleChange.fireValueChangedEvent(ListListenerHelper.java:164)
at com.sun.javafx.collections.ListListenerHelper.fireValueChangedEvent(ListListenerHelper.java:73)
at javafx.collections.ObservableListBase.fireChange(ObservableListBase.java:233)
at javafx.collections.ListChangeBuilder.commit(ListChangeBuilder.java:482)
at javafx.collections.ListChangeBuilder.endChange(ListChangeBuilder.java:541)
at javafx.collections.ObservableListBase.endChange(ObservableListBase.java:205)
at javafx.collections.ModifiableObservableListBase.add(ModifiableObservableListBase.java:155)
at java.util.AbstractList.add(AbstractList.java:108)
at QuizGUI_classes.StopWatchBar.run(StopWatchBar.java:42)
at java.lang.Thread.run(Thread.java:748)

I have no clue if im on the right path or not, hope someone has some insight.

Here is an example using Timeline. The Timeline is set to run every second. Once the counter reaches zero, the Timeline stops.

import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
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.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;

public class BarChartExperiments extends Application 

 Timeline timeline;
 int counter = 60;

 @Override
 public void start(Stage primaryStage) throws Exception 
 primaryStage.setTitle("BarChart Experiments");

 CategoryAxis xAxis = new CategoryAxis();
 xAxis.setLabel("Devices");

 NumberAxis yAxis = new NumberAxis();
 yAxis.setLabel("Visits");

 BarChart barChart = new BarChart(xAxis, yAxis);

 XYChart.Series dataSeries1 = new XYChart.Series();
 dataSeries1.setName("Time");

 barChart.getData().add(dataSeries1);
 barChart.setAnimated(false);
 dataSeries1.getData().add(new XYChart.Data("Time", counter));

 timeline = new Timeline(new KeyFrame(Duration.seconds(1), event ->
 dataSeries1.getData().add(new XYChart.Data("Time", --counter));
 System.out.println(counter);
 if(counter == 0)
 
 timeline.stop();
 
 ));
 timeline.setCycleCount(Timeline.INDEFINITE);

 Button button = new Button("Start");
 button.setOnAction(event ->
 switch(button.getText())
 
 case "Start":
 timeline.play();
 button.setText("Reset");
 break;
 case "Reset":
 timeline.stop();
 button.setText("Start");
 counter = 60;
 dataSeries1.getData().add(new XYChart.Data("Time", counter));
 break;
 
 );
 VBox vbox = new VBox(barChart, button);

 Scene scene = new Scene(vbox, 400, 200);

 primaryStage.setScene(scene);
 primaryStage.setHeight(600);
 primaryStage.setWidth(500);

 primaryStage.show();
 

 public static void main(String args) 
 Application.launch(args);
 

Altered code from here