How to get Data from table in javafx

Question

I'm tried to get data from my table using for loop but it occur null point exception. this is my code

for (int i = 0; i < tabel_otapproclInfo.getItems().size(); i++) {
            String s = tabel_otapproclInfo.getSelectionModel().getSelectedItem().getEMPLOYEEID();
            String s2 = tabel_otapproclInfo.getSelectionModel().getSelectedItem().getEMPLOYEENAME();
            String s3 = tabel_otapproclInfo.getSelectionModel().getSelectedItem().getEMPLOYEEDEPT();
            String s4 = tabel_otapproclInfo.getSelectionModel().getSelectedItem().getSTATUS();
            String s5 = tabel_otapproclInfo.getSelectionModel().getSelectedItem().getDATES();
            String u = tabel_otapproclInfo.getSelectionModel().getSelectedItem().getUSERNMAE();

            System.out.println(u + " " + s + " " + s2 + " " + s3 + " " + s4 + " " + s5);
        }

in this code tabel_otapproclInfo is table name

this is error is occerd

java.lang.NullPointerException
at ashoklayland.OTApprovelsController.actionApproverlAll(OTApprovelsController.java:126)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java:71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)

Answer 1

If you want to loop through all of the data in a Table you should take this approach. In this example, the Table object is Person.

for (int i = 0; i < table.getItems().size(); i++) 
{
    Person tempPerson = table.getItems().get(i);
    System.out.println(tempPerson.getFirstName() + " " + tempPerson.getLastName() + " " + tempPerson.getEmail());
}

If you want to get a Person from a specific index, where the index >= 0 and index < table.getItems().size(), try:

Person tempPerson = table.getItems().get(1);
System.out.println("Specifice index 1: " + tempPerson.getFirstName() + " " + tempPerson.getLastName() + " " + tempPerson.getEmail());

If you want to get the Person after it has been selected use a listener.

table.getSelectionModel().selectedItemProperty().addListener((obs, oldSelection, newSelection) -> {
    System.out.println("On Select: " + newSelection.getFirstName() + " " + newSelection.getLastName() + " " + newSelection.getEmail());
});

Full Code:

import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
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
{

    private final TableView<Person> table = new TableView();
    private final ObservableList<Person> data
            = FXCollections.observableArrayList(
                    new Person("Jacob", "Smith", "jacob.smith@example.com"),
                    new Person("Isabella", "Johnson", "isabella.johnson@example.com"),
                    new Person("Ethan", "Williams", "ethan.williams@example.com"),
                    new Person("Emma", "Jones", "emma.jones@example.com"),
                    new Person("Michael", "Brown", "michael.brown@example.com")
            );

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

    @Override
    public void start(Stage stage)
    {
        Scene scene = new Scene(new Group());
        stage.setTitle("Table View Sample");
        stage.setWidth(450);
        stage.setHeight(500);

        final Label label = new Label("Address Book");
        label.setFont(new Font("Arial", 20));

        table.setEditable(true);

        TableColumn firstNameCol = new TableColumn("First Name");
        firstNameCol.setMinWidth(100);
        firstNameCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("firstName"));

        TableColumn lastNameCol = new TableColumn("Last Name");
        lastNameCol.setMinWidth(100);
        lastNameCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("lastName"));

        TableColumn emailCol = new TableColumn("Email");
        emailCol.setMinWidth(200);
        emailCol.setCellValueFactory(
                new PropertyValueFactory<Person, String>("email"));

        table.setItems(data);
        table.getColumns().addAll(firstNameCol, lastNameCol, emailCol);

        final VBox vbox = new VBox();
        vbox.setSpacing(5);
        vbox.setPadding(new Insets(10, 0, 0, 10));
        vbox.getChildren().addAll(label, table);

        ((Group) scene.getRoot()).getChildren().addAll(vbox);

        stage.setScene(scene);
        stage.show();

        for (int i = 0; i < table.getItems().size(); i++) {
            Person tempPerson = table.getItems().get(i);
            System.out.println(tempPerson.getFirstName() + " " + tempPerson.getLastName() + " " + tempPerson.getEmail());
        }

        Person tempPerson = table.getItems().get(1);
        System.out.println("Specifice index 1: " + tempPerson.getFirstName() + " " + tempPerson.getLastName() + " " + tempPerson.getEmail());

        table.getSelectionModel().selectedItemProperty().addListener((obs, oldSelection, newSelection) -> {
            System.out.println("On Select: " + newSelection.getFirstName() + " " + newSelection.getLastName() + " " + newSelection.getEmail());
        });
    }

    public static class Person
    {

        private final SimpleStringProperty firstName;
        private final SimpleStringProperty lastName;
        private final SimpleStringProperty email;

        private Person(String fName, String lName, String email)
        {
            this.firstName = new SimpleStringProperty(fName);
            this.lastName = new SimpleStringProperty(lName);
            this.email = new SimpleStringProperty(email);
        }

        public String getFirstName()
        {
            return firstName.get();
        }

        public void setFirstName(String fName)
        {
            firstName.set(fName);
        }

        public String getLastName()
        {
            return lastName.get();
        }

        public void setLastName(String fName)
        {
            lastName.set(fName);
        }

        public String getEmail()
        {
            return email.get();
        }

        public void setEmail(String fName)
        {
            email.set(fName);
        }
    }
}