多个带控制器的FXML，共享对象

Question

我已经找到了一堆关于这个主题的帖子，但是我仍然无法将一个对象从Controller1传递到Controller2。有没有一个完整的教程或一些例子项目这样做？

我已经走了这么远，直到我被卡住了：

国家类

public class Country {
private SimpleStringProperty country = new SimpleStringProperty("");

//Constructor
public Country() {
}

//GETTERS
public String getCountry() {
    return country.get();
}

//SETTERS
public void setCountry(String value) {
    country.set(value);
}

@Override
public String toString() {
    return getCountry();
}
}

public class SampleController implements Initializable {

@FXML
private Pane pContent;

private Country c;

@FXML
private void handleButtonAction(ActionEvent event) throws IOException {
    System.out.println(c); //this prints Belgium, which is correct

    URL url = getClass().getResource("Sub1.fxml");

    FXMLLoader fxmlloader = new FXMLLoader();
    fxmlloader.setLocation(url);
    fxmlloader.setBuilderFactory(new JavaFXBuilderFactory());

    pContent.getChildren().clear();
    pContent.getChildren().add((Node) fxmlloader.load(url.openStream()));
}

@Override
public void initialize(URL url, ResourceBundle rb) {
    c = new Country();
    c.setCountry("Belgium");
}

public Country getCountryFromSampleController(){
    return c;
}
}

public class Sub1Controller implements Initializable {

/**
 * Initializes the controller class.
 */
@Override
public void initialize(URL url, ResourceBundle rb) {
    SampleController sp = new SampleController(); //I don't know how to fetch the original SampleController object
    System.out.println(sp.getCountryFromSampleController()); 
    //this prints null, which is ofcourse logical because I make a new SampleController object.         
}    
}

很抱歉这么长的帖子，我试图尽可能完整，否则我永远不会明白...

Answer 1

FXML是MVC模式的一种简单形式。FXML文件是一个视图，控制器很明显，漏掉了什么？模型--一个存储与当前视图相关的所有数据的地方，因此，您可以使用它在控制器之间共享国家数据。

1.引入模型的可能途径之一是“语境”。让我们考虑一个案例，那么整个项目只有一个模型，所以您可以以单例的形式拥有全局上下文

public class Context {
    private final static Context instance = new Context();

    public static Context getInstance() {
        return instance;
    }

    private Country country = new Country();

    public Country currentCountry() {
        return country;
    }
}

您的SampleController将有下一个更改：

@Override
public void initialize(URL url, ResourceBundle rb) {
    Context.getInstance().currentCountry().setCountry("Belgium");
}

@Override
public void initialize(URL url, ResourceBundle rb) {
    System.out.println(Context.getInstance().currentCountry().getCountry());
}

public class Sub1Controller implements Initializable {
    private Context context;
    public void setContext(Context context) {
        this.context = context;
        // initialize country dependent data here rather then in initialize()
    }
}

Context currentContext = new Context();

@Override
public void initialize(URL url, ResourceBundle rb) {
    currentContext.currentCountry().setCountry("Belgium");
}

@FXML
private void handleButtonAction(ActionEvent event) throws IOException {
    URL url = getClass().getResource("Sub1.fxml");

    FXMLLoader fxmlloader = new FXMLLoader();
    fxmlloader.setLocation(url);
    fxmlloader.setBuilderFactory(new JavaFXBuilderFactory());

    pContent.getChildren().clear();
    pContent.getChildren().add((Node) fxmlloader.load(url.openStream()));
            // here we go
    ((Sub1Controller)fxmlloader.getController()).setContext(currentContext);
}