public class DragWindowHandler implements EventHandler<MouseEvent> {

        private Stage primaryStage;        //primaryStage為start方法頭中的Stage
        private double oldStageX;
        private double oldStageY;
        private double oldScreenX;
        private double oldScreenY;

        public DragWindowHandler(Stage primaryStage) {        //構造器
            this.primaryStage = primaryStage;
        }

        @Override
        public void handle(MouseEvent e) {
            if (e.getEventType() == MouseEvent.MOUSE_PRESSED) {    //滑鼠按下的事件    
                this.oldStageX = this.primaryStage.getX();
                this.oldStageY = this.primaryStage.getY();
                this.oldScreenX = e.getScreenX();
                this.oldScreenY = e.getScreenY();

            } else if (e.getEventType() == MouseEvent.MOUSE_DRAGGED) {  //滑鼠拖動的事件
                this.primaryStage.setX(e.getScreenX() - this.oldScreenX + this.oldStageX);
                this.primaryStage.setY(e.getScreenY() - this.oldScreenY + this.oldStageY);
            }
        }
    }
 

EventHandler handler = new DragWindowHandler(this.primaryStage);        //primaryStage為start方法中的區域性b
this.setOnMousePressed(handler);    //如果去掉這一行程式碼將會使滑鼠進入面板時面板左上角會定位到滑鼠的位置
this.setOnMouseDragged(handler);