JavaFX - 如何使用来自另一个 Controller 的 Controller 中的方法？

Question

使用 SceneBuilder。我有 2 个阶段，每个阶段都有一个 Controller :
stage1Controller、
stage2Controller。
Stage1 Controller :

public class Stage1Controller {
    @FXML
    private MenuItem translate;
    @FXML
    private Menu file;
    @FXML
    private Menu edit;
    @FXML
    private Menu help;


    @FXML 
    private void handleTranslate (ActionEvent event){
        translateFirstStage();
        //HOW TO ACCESS THE stage2Controller setLabel()??
    }

    private void translateFirstStage(){
        file.setText("Fichier");
        edit.setText("Modifier");
        help.setText("Aide");
    }
}

Stage2Controller:

public class Stage2Controller {
    @FXML
    private Label lb;


    private void setLabel(String string){
        lb.setText("string");
    }
}

下面是两个 fxml 文件是如何使用两种方法加载到 Main.java 类中的
(在 Start(Stage primaryStage) 方法中调用):

public void firstStage() {
        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(Main.class.getResource("view/stage1.fxml"));
            rootLayout = (BorderPane) loader.load();

            // Show the scene containing the root layout.
            Scene scene = new Scene(rootLayout);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void secondStage() {

        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(Main.class.getResource("view/stage2.fxml"));
            XD = (AnchorPane) loader.load();

            // Show the scene containing the root layout.
            Scene scene = new Scene(XD);
            Stage stage = new Stage();
            stage.setScene(scene);
            stage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

• handleTranslate(ActionEvent event) 方法用作第一个 Stage 中 MenuItem translate 的 OnAction 方法，它翻译 View 在两个阶段。
  

如何将 setLabel 放入 handleTranslate 方法中？谢谢

Answer 1

“快速而肮脏”的方法是为 Stage1Controller 提供对 Stage2Controller 的引用:

public class Stage1Controller {

    private final Stage2Controller stage2Controller ;

    public void setStage2Controller(Stage2Controller stage2Controller) {
        this.stage2Controller = stage2Controller ;
    }

    // ...

    @FXML 
    private void handleTranslate (ActionEvent event){
        translateFirstStage();
        stage2Controller.setLabel(...);
    }

    // other code as before ...
}

现在在您的主应用中:

public class MainApp  extends Application {

    private Stage1Controller stage1Controller ;
    private Stage2Controller stage2Controller ;

    @Override
    public void start(Stage primaryStage) {
        firstStage();
        secondStage();

        stage1Controller.setStage2Controller(stage2Controller);

        // ...
    }

    public void firstStage() {
        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(Main.class.getResource("view/stage1.fxml"));
            rootLayout = (BorderPane) loader.load();

            stage1Controller = loader.getController();

            // Show the scene containing the root layout.
            Scene scene = new Scene(rootLayout);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void secondStage() {

        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(Main.class.getResource("view/stage2.fxml"));
            XD = (AnchorPane) loader.load();

            stage2Controller = loader.getController();

            // Show the scene containing the root layout.
            Scene scene = new Scene(XD);
            Stage stage = new Stage();
            stage.setScene(scene);
            stage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // ...
}

不过，一个更稳健的方法是让两个 Controller 访问共享模型类，存储数据。如果您使用 JavaFX 可观察属性表示数据，则 Controller 可以监听它们关心的属性的变化。例如:

public class Model {

    private final StringProperty text = new SimpleStringProperty("Initial text...");

    public StringProperty textProperty() {
        return text ;
    }

    public final void setText(String text) {
        textProperty().set(text);
    }

    public final String getText() {
        return textProperty().get();
    }

    // other properties as needed...
}

现在你的 Controller 看起来像这样:

public class Stage1Controller {

    private Model model ;

    public void setModel(Model model) {
        this.model = model ;
    }

    @FXML 
    private void handleTranslate (ActionEvent event){
        translateFirstStage();

        model.setText(...); // value will appear in stage2 controller's label!
    }

    // ...
}

和

public class Stage2Controller {

    @FXML
    private Label lb ;

    private Model model ;

    public void setModel(Model model) {
        lb.textProperty().unbind();
        this.model = model ;
        lb.textProperty().bind(model.textProperty());
    }

    // ...
}

在这种情况下，您的主应用程序如下所示:

public class MainApp extends Application {

    private final Model = new Model();

    @Override
    public void start(Stage primaryStage) {
        // ...
    }

    public void firstStage() {
        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(Main.class.getResource("view/stage1.fxml"));
            rootLayout = (BorderPane) loader.load();

            Stage1Controller controller = loader.getController();
            controller.setModel(model);

            // Show the scene containing the root layout.
            Scene scene = new Scene(rootLayout);
            primaryStage.setScene(scene);
            primaryStage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void secondStage() {

        try {
            // Load root layout from fxml file.
            FXMLLoader loader = new FXMLLoader();
            loader.setLocation(Main.class.getResource("view/stage2.fxml"));
            XD = (AnchorPane) loader.load();

            Stage2Controller controller = loader.getController();
            controller.setModel(model);

            // Show the scene containing the root layout.
            Scene scene = new Scene(XD);
            Stage stage = new Stage();
            stage.setScene(scene);
            stage.show();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}