JavaFX Task example

TaskTest.java

import javafx.application.Application;
import javafx.beans.value.*;
import javafx.collections.*;
import javafx.concurrent.*;
import javafx.event.*;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.stage.Stage;
 
public class TaskTest extends Application {
  public static void main(String[] args) throws Exception { launch(args); }
  public void start(final Stage stage) throws Exception {
    final Label statusLabel = new Label("Status");
    final Button runButton = new Button("Run");
    final ListView<String> peopleView = new ListView<String>();
    peopleView.setPrefSize(220, 162);
    final ProgressBar progressBar = new ProgressBar();
    progressBar.prefWidthProperty().bind(peopleView.prefWidthProperty());
 
    runButton.setOnAction(new EventHandler<ActionEvent>() {
      @Override public void handle(ActionEvent actionEvent) {
        final Task task = new Task<ObservableList<String>>() {
          @Override protected ObservableList<String> call() throws InterruptedException {
            updateMessage("Finding friends . . .");
            for (int i = 0; i < 10; i++) {
              Thread.sleep(200);
              updateProgress(i+1, 10);
            }
            updateMessage("Finished.");
            return FXCollections.observableArrayList("John", "Jim", "Geoff", "Jill", "Suki");
          }
//          @Override protected void done() {
//            super.done();
//            System.out.println("This is bad, do not do this, this thread " + Thread.currentThread() + " is not the FXApplication thread.");
//            runButton.setText("Voila!");
//          }
        };
 
        statusLabel.textProperty().bind(task.messageProperty());
        runButton.disableProperty().bind(task.runningProperty());
        peopleView.itemsProperty().bind(task.valueProperty());
        progressBar.progressProperty().bind(task.progressProperty());
        task.stateProperty().addListener(new ChangeListener<Worker.State>() {
          @Override public void changed(ObservableValue<? extends Worker.State> observableValue, Worker.State oldState, Worker.State newState) {
            if (newState == Worker.State.SUCCEEDED) {
              System.out.println("This is ok, this thread " + Thread.currentThread() + " is the JavaFX Application thread.");
              runButton.setText("Voila!");
            }
          }
        });
 
        new Thread(task).start();
      }
    });
 
    final VBox layout =
      VBoxBuilder.create().spacing(8).children(
        VBoxBuilder.create().spacing(5).children(
          HBoxBuilder.create().spacing(10).children(
            runButton,
            statusLabel).build(),
          progressBar
        ).build(),
        peopleView
      ).build();
    layout.setStyle("-fx-background-color: cornsilk; -fx-padding:10; -fx-font-size: 16;");
    Scene scene = new Scene(layout);
    stage.setScene(scene);
    stage.show();
  }
}