我正在編寫一個類似于打磚塊的簡單游戲。有必要按左箭頭進行平臺移動。負責點擊按鈕的代碼：                    canvas.requestFocus();                    canvas.setOnKeyTyped(new EventHandler<KeyEvent>() {                        @Override                        public void handle(KeyEvent event) {                            if (event.getCode() == KeyCode.LEFT) {                                System.out.println("Leffft");                                platform.LeftShift();                                event.consume();                            }                        }                    });問題是，當您啟動并按下按鈕時，什么也沒有發(fā)生。游戲場.javaimport javafx.animation.KeyFrame;import javafx.animation.Timeline;import javafx.application.Application;import javafx.event.ActionEvent;import javafx.event.EventHandler;import javafx.scene.input.KeyCode;import javafx.scene.input.KeyEvent;import javafx.scene.layout.Pane;import javafx.scene.paint.Color;import javafx.stage.Stage;import javafx.scene.Scene;import javafx.util.Duration;public class GameField extends Application {public static GameField me;public GameField(){    me=this;}static Pane canvas = new Pane();static Ball ball = new Ball(5, Color.WHITE);static Platform platform = new Platform(80,5, Color.WHITE);Scene scene = new Scene(canvas,550,500, Color.BLACK);static Timeline timeline;@Overridepublic void start(Stage stage) {    canvas.getChildren().add(ball);    canvas.getChildren().add(platform);    ball.relocate(50, 50);    platform.relocate(235,495);    stage.setScene(scene);    stage.setTitle("Cat Arcanoid");    stage.show();左移方法public void LeftShift(){    double dx = 10;    GameField.platform.relocate(getLayoutX()-dx, getLayoutY());}