JavaFX通过initialize方法实现Post render事件

Question

执行初始化方法后，我需要立即用一些文本消息更新 Controller 。这意味着 UI 的发布(由于用户需要看到出现此消息)。我见过类似帖子 Post render event in JavaFX 的一些解决方案, How to listen for WindowEvent.WINDOW_SHOWN 。但似乎我无法用这些解决方案完成我的任务。

作为解决方案当我按以下方式使用 WindowEvent.WINDOW_SHOWN 时，它将尝试执行我已声明的事件处理程序位置(在应用程序的早期阶段)，这意味着当舞台初始化时(执行应用程序的start(Stage stage)) 然后我得到了一些空指针异常。我的应用程序有许多 Controller ，我需要在某些 UI 流程的中间进行此操作。一旦执行特定 Controller 的初始化方法(在渲染后阶段)，如何完成此任务。谢谢。

@Override
public void start(Stage stage) throws Exception
{
    FXMLLoader loader = new FXMLLoader();
    Parent root = (Parent)loader.load(TestController.class.getResourceAsStream("TestView.fxml"));
    final TestController controller = (TestController)loader.getController();
    stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>()
    {
         @Override
        public void handle(WindowEvent window)
        {
            controller.handleWindowShownEvent();
        }
    }
    });
    Scene scene = new Scene(root);
    stage.setScene(scene);
    stage.show();
}

如下在我的应用程序中当我添加事件处理程序并使用 Spring Context 加载相关 Controller 时，它将产生空指针异常。

通过handleWindowShowEvent方法，我使用了我声明的所有UI组件和资源包。当该方法要执行时，它将通过这些 UI Controller 和资源包调用生成空指针异常。

问题是，由于 UI 尚未渲染，初始化 block 似乎尚未执行，但 handleWindowShowEvent 方法将使用那些未初始化的组件。

添加事件处理程序

  stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() {

    @Override
    public void handle(WindowEvent window) {

         Platform.runLater(new Runnable() {
            @Override
            public void run() {

              try {

                  // Load Controller with Spring Context
                  EquipmentConfigProcessController eqConfProcessController
                          = ComponentUtil.appContext.getBean(EquipmentConfigProcessController.class);

                  eqConfProcessController.handleWindowShowEvent();

              } catch (Exception e) {
                  logger.error("Exception while going to execute handleWindowShowEvent method on " +
                          "EquipmentConfigProcessController [" + e.getMessage() + "]");
              }
          }
        });
    }
});

初始化方法

      private ResourceBundle rb;
@FXML private Pane detailPane;
@FXML private HBox detailBox;
@FXML public Label devNameLbl;

@Override
public void initialize(URL url, ResourceBundle rb) {

 // Initialise resource bundle
 this.rb = rb;
}

handleWindowShowEvent方法

   public void handleWindowShowEvent() {

        // Null Pointer Exception occurred with Resource ResourceBundle 
        Label updateMessage = new Label(rb.getString("equipment.message"));

        // Null Pointer Exception occurred with detailBox invocation  
        detailBox.getChildren().clear();

        // More codes
   }

Answer 1

尝试为

stage.addEventHandler(WindowEvent.WINDOW_SHOWN, new EventHandler<WindowEvent>() {
    @Override
    public void handle(WindowEvent window) {
        Platform.runLater(new Runnable() {
            @Override
            public void run() {
                controller.handleWindowShownEvent();
            }
        });
    }
});