在javafx表中设置项目，我做错了什么？

Question

I have to initialize a javafx table and I have no idea what is going wrong. I used this: https://docs.oracle.com/javafx/2/ui_controls/table-view.htm tutorial and I am also using SceneBuilder and FXML to make the GUI.

Main class: This sets the window up and creates the table, along with all of the columns and the like. It also makes sure to open or create the file that will be read from and written to.

public class Main extends Application {

    private AnchorPane rootLayout;

    public void initialize ()
    {
        System.out.println("Initialized");
        try {

            File masterFile = new File(("G:\\"),"masterfile.txt"); //I just needed to create the file to be able to access it at a later date


             if (!masterFile.exists()){

                 masterFile.createNewFile();

             }

             MainScreenController table = new MainScreenController();

            table.initializeTable();

             System.setProperty("glass.accessible.force", "false");

        } catch (Exception e) {

            System.out.println("INITIALIZE METHOD WENT HAYWIRE");

        }
    }
    @Override
    public void start(Stage primaryStage) {
        try {
            FXMLLoader root = new FXMLLoader();

            root.setLocation(Main.class.getResource("view/MainScreen.fxml"));
            rootLayout = (AnchorPane) root.load();
            Scene scene = new Scene(rootLayout);
            primaryStage.setResizable(false);
            primaryStage.setScene(scene);
            primaryStage.show();
            initialize();
        } catch(Exception e) {
            e.printStackTrace();
        }
    }




    public static void main(String[] args) {
        launch(args);
    }


}

the controller class of the table: This is my attempt at making the columns be populated by the data I have.

@FXML
public Button showAddNewPerson;
@FXML
public Button EditStudentFiles;
@FXML
public Button generateDebtorReport;
@FXML
public Button generateSeniorReport;
@FXML
public TableView<StudentData> dataTable = new TableView<StudentData>();
@FXML
private TableColumn<StudentData, String> firstNameCol = new TableColumn<StudentData, String>();
@FXML
private TableColumn<StudentData, String> lastNameCol = new TableColumn<StudentData, String>();
@FXML
private TableColumn<StudentData, String> schoolCol = new TableColumn<StudentData, String>();
@FXML
private TableColumn<StudentData, String> stateCol = new TableColumn<StudentData, String>();
@FXML
private TableColumn<StudentData, String> emailCol = new TableColumn<StudentData, String>();
@FXML
private TableColumn<StudentData, Integer> yearJoinedCol = new TableColumn<StudentData, Integer>();
@FXML
private TableColumn<StudentData, String> activeCol = new TableColumn<StudentData, String>();
@FXML
private TableColumn<StudentData, Double> debtCol = new TableColumn<StudentData, Double>();

public AnchorPane addNewPersonLayout;

@SuppressWarnings("unchecked")
public void initializeTable() {


    ObservableList<StudentData> observableData = FXCollections.observableArrayList(StudentData.retrieveDataFromFile());//retrieves the array list from the file

    //I think these statements pick out each instance variable of each object in the arrayList
    firstNameCol.setCellValueFactory(new PropertyValueFactory<StudentData, String>("firstName"));
    lastNameCol.setCellValueFactory(new PropertyValueFactory<StudentData, String>("lastName"));
    schoolCol.setCellValueFactory(new PropertyValueFactory<StudentData, String>("schoolName"));
    stateCol.setCellValueFactory(new PropertyValueFactory<StudentData, String>("stateAbbreviaion"));
    emailCol.setCellValueFactory(new PropertyValueFactory<StudentData, String>("studentEmail"));
    yearJoinedCol.setCellValueFactory(new PropertyValueFactory<StudentData, Integer>("yearJoined"));
    activeCol.setCellValueFactory(new PropertyValueFactory<StudentData, String>("areTheyActive"));
    debtCol.setCellValueFactory(new PropertyValueFactory<StudentData, Double>("amountOwed"));

    //sets observable list into the table
    dataTable.setItems(observableData);
    //this is what the tutorial says works
    dataTable.getColumns().addAll(firstNameCol, lastNameCol, schoolCol, stateCol, emailCol, yearJoinedCol, activeCol, debtCol);
}

I don't really understand how this table is supposed to work as the tutorial confuses me a little.

Answer 1

First of all, make sure that you have defined the controller class in your FXML.

<YourRootElement fx:controller="MyControllerClass">

Then, i'm not sure why you are creating new instances of your "visual elements" and why are you defining them as public, but if you are using JavaFX 8, you neet to define them like this:

@FXML
private TableView<StudentData> dataTable;

about your Table, you have 3 options:

1. (The best one) Initialize the Table inside the controller. You should create your initialize methon on the controller to fill all your data before calling the "show" method on the main. That method will be called by default by the JRE... And please be sure to have Getters for your Student Class.

    public ControllerClass{ //All your variables and Stuff @FXML private void initialize(){ //here is where you initialize your data } } 

2. There's a little trick to force the table to update, but since I'm not 100% sure that you are collecting correctly your data, I can't guarantee it to work. Place this code after you add items to your ObservableList

    dataTable.getColumns().get(0).setVisible(false); dataTable.getColumns().get(0).setVisible(true);