JAVAFX - 通过不同场景传递数据

Question

我正在尝试创建一个具有登录功能的库，并且我需要知道哪些用户在我的所有场景中登录。

我正在尝试通过 SceneController 将登录详细信息（来自数据库的响应）从 LoginController 发送到 MainController。

在 SceneController 中，我通过保存资源文件名和当前阶段的参数来更改场景。

登录控制器.java

public class LoginController implements Initializable {
    @FXML
    private Button cancelButton;
    @FXML
    private Button loginButton;
    @FXML
    private Label loginMessageLabel;
    @FXML
    private TextField usernameField;
    @FXML
    private TextField passwordField;

    public void initialize(URL url, ResourceBundle resourceBundle){
    }

    public void loginButtonOnAction(ActionEvent event){
        if(!usernameField.getText().isBlank() && !passwordField.getText().isBlank()){
            validateLogin();
        }else{
            loginMessageLabel.setText("Datele introduse nu sunt corecte!");
        }
    }

    public void cancelButtonOnAction(ActionEvent event){
        Stage stage = (Stage) cancelButton.getScene().getWindow();
        stage.close();
    }

    public void validateLogin(){
        DatabaseConnection connectionNew = new DatabaseConnection();
        Connection connectDB = connectionNew.getConnection();

        String verifyLogin = "SELECT count(1), id, name FROM users WHERE Username= '"+usernameField.getText()+"' AND Password ='"+passwordField.getText()+"'";
        System.out.println(verifyLogin);
        try{

            Statement statement = connectDB.createStatement();
            ResultSet queryResult = statement.executeQuery(verifyLogin);

            while(queryResult.next()){

                if(queryResult.getInt(1) == 1){
                    Stage stage = (Stage) loginButton.getScene().getWindow();
                    SceneController sceneController = new SceneController();
                    sceneController.switchScene(stage, "main-view.fxml");
                }else{
                    loginMessageLabel.setText("Datele introduse nu sunt corecte!");
                }

            }

        }catch (Exception e){
            throw new RuntimeException("unhandled", e);
        }
    }

}

主控制器.java

public class MainController implements Initializable {

    private static String paneName;
    private static String userId;
    private static String defaultImagePath = "C:\\Users\\costi\\Desktop\\LibraryImages\\";
    private static String defaultImageName = "default.png";
    public TableView<Book> tableViewSearch, tableViewHome;
    public TableColumn<Book,String> colSearchTitle, colHomeTitle, colSearchPublicatedOn, colHomePublicatedOn, colSearchPublishingHouse, colHomePublishingHouse, colSearchSummary, colHomeSummary;
    public TableColumn<Book,Integer> colSearchPrice, colHomePrice, colSearchId, colHomeId;
    @FXML
    private Button cancelButton, menuHomeButton, menuSearchButton, borrowBookButton;
    @FXML
    private Pane paneHome, paneSearch, paneBookDetails;
    @FXML
    private TextField searchField, titleField, publishingHouseField, priceField, bookIdField, userIdField;
    @FXML
    private DatePicker publishedOnField;
    @FXML
    private TextArea summaryTextArea;
    @FXML
    private FlowPane flowPaneCoverImage;

    public void initialize(URL url, ResourceBundle resourceBundle) {
        paneHome.toFront();
        setPaneName("paneHome");
        setMainData();
    }
    public void setMainData(){
        colHomeId.setCellValueFactory(new PropertyValueFactory<>("Id"));
        colHomeTitle.setCellValueFactory(new PropertyValueFactory<>("Title"));
        colHomePublicatedOn.setCellValueFactory(new PropertyValueFactory<>("PublicatedOn"));
        colHomePublishingHouse.setCellValueFactory(new PropertyValueFactory<>("PublishingHouse"));
        colHomeSummary.setCellValueFactory(new PropertyValueFactory<>("Summary"));
        colHomePrice.setCellValueFactory(new PropertyValueFactory<>("Price"));
        HomeController homeController = new HomeController();
        tableViewHome.setRowFactory( tv -> {
            TableRow<Book> row = new TableRow<>();
            row.setOnMouseClicked(event -> {
                if (event.getClickCount() == 2 && (! row.isEmpty()) ) {
                    paneBookDetails.toFront();
                    Book rowData = row.getItem();

                    String date = rowData.getPublicatedOn();
                    var dateTimeFormatter = DateTimeFormatter.ofPattern("dd.MM.yyyy");
                    var dateTime = LocalDate.parse(date, dateTimeFormatter);

                    bookIdField.setText(Integer.toString(rowData.getId()));
                    titleField.setText(rowData.getTitle());
                    publishingHouseField.setText(rowData.getPublishingHouse());
                    priceField.setText(Integer.toString(rowData.getPrice()));
                    publishedOnField.setValue(dateTime);
                    summaryTextArea.setText(rowData.getSummary());

                    InputStream stream = null;
                    try {
                        stream = new FileInputStream(defaultImagePath + rowData.getCover());
                    } catch (FileNotFoundException e) {
                        try {
                            stream = new FileInputStream(defaultImagePath + defaultImageName);
                        } catch (FileNotFoundException ex) {
                        }
                    }

                    Image image = new Image(stream);
                    ImageView imageView = new ImageView(image);
                    imageView.setFitHeight(flowPaneCoverImage.getHeight());
                    imageView.setFitWidth(flowPaneCoverImage.getWidth());
                    flowPaneCoverImage.getChildren().clear();
                    flowPaneCoverImage.getChildren().add(imageView);
                }
            });
            return row ;
        });

        tableViewHome.setItems(homeController.getBooks());
    }

    public void searchButtonOnAction(ActionEvent event) {
        colSearchId.setCellValueFactory(new PropertyValueFactory<>("Id"));
        colSearchTitle.setCellValueFactory(new PropertyValueFactory<>("Title"));
        colSearchPublicatedOn.setCellValueFactory(new PropertyValueFactory<>("PublicatedOn"));
        colSearchPublishingHouse.setCellValueFactory(new PropertyValueFactory<>("PublishingHouse"));
        colSearchSummary.setCellValueFactory(new PropertyValueFactory<>("Summary"));
        colSearchPrice.setCellValueFactory(new PropertyValueFactory<>("Price"));
        tableViewSearch.setRowFactory( tv -> {
            TableRow<Book> row = new TableRow<>();
            row.setOnMouseClicked(ev -> {
                if (ev.getClickCount() == 2 && (! row.isEmpty()) ) {
                    paneBookDetails.toFront();
                    Book rowData = row.getItem();

                    String date = rowData.getPublicatedOn();
                    var dateTimeFormatter = DateTimeFormatter.ofPattern("dd.MM.yyyy");
                    var dateTime = LocalDate.parse(date, dateTimeFormatter);

                    bookIdField.setText(Integer.toString(rowData.getId()));
                    titleField.setText(rowData.getTitle());
                    publishingHouseField.setText(rowData.getPublishingHouse());
                    priceField.setText(Integer.toString(rowData.getPrice()));
                    publishedOnField.setValue(dateTime);
                    summaryTextArea.setText(rowData.getSummary());

                    InputStream stream = null;
                    try {
                        stream = new FileInputStream(defaultImagePath + rowData.getCover());
                    } catch (FileNotFoundException e) {
                        try {
                            stream = new FileInputStream(defaultImagePath + defaultImageName);
                        } catch (FileNotFoundException ex) {
                        }
                    }

                    Image image = new Image(stream);
                    ImageView imageView = new ImageView(image);
                    imageView.setFitHeight(flowPaneCoverImage.getHeight());
                    imageView.setFitWidth(flowPaneCoverImage.getWidth());
                    flowPaneCoverImage.getChildren().clear();
                    flowPaneCoverImage.getChildren().add(imageView);
                }
            });
            return row ;
        });
        SearchController searchController = new SearchController();
        tableViewSearch.setItems(searchController.getBooks(searchField.getText()));
    }

    public void cancelButtonOnAction(ActionEvent event){
        Stage stage = (Stage) cancelButton.getScene().getWindow();
        stage.close();
    }

    public void menuButtonOnAction(ActionEvent event){
        if(event.getSource() == menuHomeButton){
            setPaneName("paneHome");
            paneHome.toFront();
            setMainData();
        }else if(event.getSource() == menuSearchButton){
            setPaneName("paneSearch");
            paneSearch.toFront();
        }
    }

    public void backButtonOnAction(ActionEvent event){
        var lastPannelName = getPaneName();

        System.out.println(lastPannelName);

        if(lastPannelName == "paneHome"){
            paneHome.toFront();
        }else if(lastPannelName == "paneSearch"){
            paneSearch.toFront();
        }
    }

    public void borrowBookOnAction(ActionEvent event){
        HomeController homeController = new HomeController();
        var currentBookId = Integer.valueOf(bookIdField.getText());
        try {
            homeController.borrowBook(1, 1);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }

        System.out.println((currentBookId));
    }

    public static String getPaneName() {
        return paneName;
    }

    public void display(String ceva){
        System.out.println(ceva);
    }

    public static void setPaneName(String paneName) {
        MainController.paneName = paneName;
    }

}

场景控制器.java

public class SceneController {

    private double xOffset = 0;
    private double yOffset = 0;

    public void switchScene(Stage stage, String file) throws IOException {
        Parent root = FXMLLoader.load(getClass().getResource(file));
        
        root.setOnMousePressed(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                xOffset = event.getSceneX();
                yOffset = event.getSceneY();
            }
        });

        root.setOnMouseDragged(new EventHandler<MouseEvent>() {
            @Override
            public void handle(MouseEvent event) {
                stage.setX(event.getScreenX() - xOffset);
                stage.setY(event.getScreenY() - yOffset);
            }
        });

        stage.setScene(new Scene(root));
        stage.show();
    }

}

Answer 1

使用方法：

• 传递参数 JavaFX FXML

在 中SceneController.switchScene，替换：

Parent root = FXMLLoader.load(getClass().getResource(file));

和：

FXMLLoader loader = new FXMLLoader(
   getClass().getResource(
      file
   )
); 

Parent root = loader.load();
Controller controller = loader.getController();

// do other stuff

return controller;

返回 aController来自switchScene.

然后使用它：

MainController mainController = (MainController)
    sceneController.switchScene(stage, "main-view.fxml");
mainController.setLoginDetails(loginDetails);

备择方案

还有其他选项可以执行此操作（有些选项可以避免强制转换）。

例如，

• 将登录详细信息传递给 switchScene 方法，该方法从加载器获取控制器并在其上设置登录详细信息，或者
• 预先创建控制器，在其上设置登录详细信息并将控制器传递给 switchScene 方法，该方法在加载之前在加载器上设置控制器，或者
• 使用控制器工厂机制，比如来自 eden 的聪明的东西，或者
• 应用MVC 方法。