How to make table column with formula

Question

Hi all..
This is my class
public class MyNumber{
     private int num;
     public int getNum(){
          return num;
     public void setNum( int num){
          this.num = num;
}Consider I design a table with FXML editor ( Scene Builder in this case )
and these are some of my codes
private TableView tab;
private TableColumn<MyNumber, Integer> tabColInput;
private TableColumn tabColOutput;
tab.setEditable(true);
tabColInput.setEditable(true);
tabColInput.setCellValueFactory( new PropertyValueFactory<Person,Integer>("num") );
tabColInput.setCellFactory(TextFieldTableCell.forTableColumn());
tabColInput.setOnEditCommit(
    new EventHandler<CellEditEvent<MyNumber, Integer>>() {
        @Override
        public void handle(CellEditEvent<MyNumber, Integer> t) {
            ((MyNumber) t.getTableView().getItems().get(
                t.getTablePosition().getRow())
                ).setNum(t.getNewValue());
);Problem:
I want to make tabColOutput to always show the result for tabColInput times 2
eg:
When I change a row in tabColInput to 10, tabColOutput will show 20
When I change a row in tabColInput to 3, tabColOutput will show 6
Could anyone advice me how to do this?
Ps: I am not english native speaker, so I am sorry if I am saying it wrong ^^

Answer 1

I just give it a try and it works like magic
Here is how I do it (change a cell from a table by code)
import java.util.ArrayList;
import java.util.List;
import javafx.application.Application;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.geometry.Insets;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;
public class TableViewSample extends Application {
    public static final String Column1MapKey = "A";
    public static final String Column2MapKey = "B";
    public static void main(String[] args) {
        launch(args);
    @Override
    public void start(Stage stage) {
        List<MyTableData> listData = new ArrayList<MyTableData>();
        listData.add(new MyTableData("A", 21) );
        listData.add(new MyTableData("B", 24) );
        listData.add(new MyTableData("C", 23) );
        listData.add(new MyTableData("D", 21) );
        listData.add(new MyTableData("E", 22) );
        ObservableList<MyTableData> tableData = FXCollections.observableArrayList(listData);
        Scene scene = new Scene(new Group());
        stage.setTitle("Table View Sample");
        stage.setWidth(300);
        stage.setHeight(500);
        final Label label = new Label("Student IDs");
        label.setFont(new Font("Arial", 20));
        TableColumn<MyTableData, String> firstDataColumn = new TableColumn<MyTableData, String>("NAME");
        TableColumn<MyTableData, Integer> secondDataColumn = new TableColumn<MyTableData, Integer>("AGE");
        firstDataColumn.setCellValueFactory(new PropertyValueFactory<MyTableData, String>("name"));
//        firstDataColumn.setCellValueFactory(new Callback<TableColumn.CellDataFeatures<MyTableData, String>, ObservableValue<String>>(){
//            @Override
//            public ObservableValue<String> call(CellDataFeatures<MyTableData, String> p) {
//                return p.getValue().nameProperty();
        firstDataColumn.setMinWidth(130);
        secondDataColumn.setCellValueFactory(new PropertyValueFactory<MyTableData, Integer>("age"));
        secondDataColumn.setMinWidth(130);
        TableView<MyTableData> table_view = new TableView<MyTableData>();
        table_view.setItems(tableData);
        table_view.getColumns().setAll(firstDataColumn, secondDataColumn);
        final VBox vbox = new VBox();
        vbox.setSpacing(5);
        vbox.setPadding(new Insets(10, 0, 0, 10));
        vbox.getChildren().addAll(label, table_view);
        ((Group) scene.getRoot()).getChildren().addAll(vbox);
        stage.setScene(scene);
        stage.show();
        //(this is where I change my table content with code)
        tableData.get(0).setName("xx Gargoyle xx");
        System.out.println("Testing Done");
import javafx.beans.property.SimpleStringProperty;
import javafx.beans.property.StringProperty;
public class MyTableData{
    private final SimpleStringProperty name;
    private int age;
    public MyTableData(String name, int age) {
        this.name = new SimpleStringProperty(name);
        this.age = age;
    public String getName() {
        return name.get();
    public StringProperty nameProperty(){
        return name;
    public void setName(String name) {
        this.name.set(name);
    public int getAge() {
        return age;
    public void setAge(int age) {
        this.age = age;
}And thank you very much