按下按钮时 javafx 循环

Question

我无法在按下按钮时使其循环，并在释放按钮时停止循环。

btnUp.pressedProperty().addListener((observable, wasPressed, pressed) -> {
    System.out.println("changed");
    if (pressed) {
        System.out.println("pressed");
        while(btnUp.isArmed()){ 
            try        
            {
                Thread.sleep(1000);
            } 
            catch(InterruptedException ex) 
            {
                Thread.currentThread().interrupt();
            }
            //moveflag = false;
            System.out.println("pressed");
        }
    } else {
        System.out.println("released");
    }
});

Answer 1

1. 不要在 UI 操作中使用 Thread.sleep()，它会阻止所有 UI 绘制
2. 不要在changelistener中使用while，只需有一个单独的循环来检查按钮的状态

3. 时间线最适合此类循环

   public void start(Stage stage) {
    Button btn = new Button("Press me");
   
    Timeline timeline = new Timeline(new KeyFrame(Duration.seconds(1), (ActionEvent event) -> {
       // this code will be called every second
       System.out.println(btn.isPressed() ? "pressed" : "released");
    }));
    timeline.setCycleCount(Timeline.INDEFINITE);
    timeline.play();
   
   
    StackPane root = new StackPane();
    root.getChildren().add(btn);
   
    Scene scene = new Scene(new StackPane(btn), 300, 250);
    stage.setTitle("Hello World!");
    stage.setScene(scene);
    stage.show();
   

   }