Windows

Creating a new Window

To show some content in a new window, a Stage needs to be created. After creation and initialisation show or showAndWait needs to be called on the Stage object:

// create sample content
Rectangle rect = new Rectangle(100, 100, 200, 300);
Pane root = new Pane(rect);
root.setPrefSize(500, 500);

Parent content = root;

// create scene containing the content
Scene scene = new Scene(content);

Stage window = new Stage();
window.setScene(scene);

// make window visible
window.show();

Note: This code needs to be executed on the JavaFX application thread.

Creating Custom Dialog

You can create custom dialogs which contains many component and perform many functionality on it. It behaves like second stage on owner stage.
In the following example an application that shows person in the main stage tableview and creates a person in a dialog (AddingPersonDialog) prepared. GUIs created by SceneBuilder, but they can be created by pure java codes.

Sample Application:

AppMain.java

package customdialog;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class AppMain extends Application {

    @Override
    public void start(Stage primaryStage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("AppMain.fxml"));
        Scene scene = new Scene(root, 500, 500);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

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

}

AppMainController.java

package customdialog;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.stage.Modality;
import javafx.stage.Stage;

public class AppMainController implements Initializable {

    @FXML
    private TableView<Person> tvData;
    @FXML
    private TableColumn colId;
    @FXML
    private TableColumn colName;
    @FXML
    private TableColumn colAge;

    private ObservableList<Person> tvObservableList = FXCollections.observableArrayList();

    @FXML
    void onOpenDialog(ActionEvent event) throws IOException {
        FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("AddPersonDialog.fxml"));
        Parent parent = fxmlLoader.load();
        AddPersonDialogController dialogController = fxmlLoader.<AddPersonDialogController>getController();
        dialogController.setAppMainObservableList(tvObservableList);

        Scene scene = new Scene(parent, 300, 200);
        Stage stage = new Stage();
        stage.initModality(Modality.APPLICATION_MODAL);
        stage.setScene(scene);
        stage.showAndWait();
    }

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        colId.setCellValueFactory(new PropertyValueFactory<>("id"));
        colName.setCellValueFactory(new PropertyValueFactory<>("name"));
        colAge.setCellValueFactory(new PropertyValueFactory<>("age"));
        tvData.setItems(tvObservableList);
    }

}

AppMain.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.Button?>
<?import javafx.scene.control.TableColumn?>
<?import javafx.scene.control.TableView?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.VBox?>

<AnchorPane maxHeight="400.0" minHeight="400.0" minWidth="500.0" xmlns="https://javafx.com/javafx/8.0.111" xmlns:fx="https://javafx.com/fxml/1" fx:controller="customdialog.AppMainController">
   <children>
      <VBox alignment="CENTER" layoutX="91.0" layoutY="85.0" spacing="10.0" AnchorPane.bottomAnchor="30.0" AnchorPane.leftAnchor="30.0" AnchorPane.rightAnchor="30.0" AnchorPane.topAnchor="30.0">
         <children>
            <Button mnemonicParsing="false" onAction="#onOpenDialog" text="Add Person" />
            <TableView fx:id="tvData" prefHeight="300.0" prefWidth="400.0">
              <columns>
                <TableColumn fx:id="colId" prefWidth="75.0" text="ID" />
                <TableColumn fx:id="colName" prefWidth="75.0" text="Name" />
                  <TableColumn fx:id="colAge" prefWidth="75.0" text="Age" />
              </columns>
               <columnResizePolicy>
                  <TableView fx:constant="CONSTRAINED_RESIZE_POLICY" />
               </columnResizePolicy>
            </TableView>
         </children>
      </VBox>
   </children>
</AnchorPane>

AddPersonDialogController.java

package customdialog;

import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.Node;
import javafx.scene.control.TextField;
import javafx.stage.Stage;

public class AddPersonDialogController  {
    
    @FXML
    private TextField tfId;

    @FXML
    private TextField tfName;

    @FXML
    private TextField tfAge;
    
    private ObservableList<Person> appMainObservableList;

    @FXML
    void btnAddPersonClicked(ActionEvent event) {
        System.out.println("btnAddPersonClicked");
        int id = Integer.valueOf(tfId.getText().trim());
        String name = tfName.getText().trim();
        int iAge = Integer.valueOf(tfAge.getText().trim());
        
        Person data = new Person(id, name, iAge);
        appMainObservableList.add(data);
        
        closeStage(event);
    }

    public void setAppMainObservableList(ObservableList<Person> tvObservableList) {
        this.appMainObservableList = tvObservableList;
        
    }

    private void closeStage(ActionEvent event) {
        Node  source = (Node)  event.getSource(); 
        Stage stage  = (Stage) source.getScene().getWindow();
        stage.close();
    }

}

AddPersonDialog.fxml

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.VBox?>
<?import javafx.scene.text.Text?>

<AnchorPane minHeight="300.0" minWidth="400.0" xmlns="https://javafx.com/javafx/8.0.111" xmlns:fx="https://javafx.com/fxml/1" fx:controller="customdialog.AddPersonDialogController">
   <children>
      <VBox alignment="CENTER" layoutX="131.0" layoutY="50.0" prefHeight="200.0" prefWidth="100.0" AnchorPane.bottomAnchor="5.0" AnchorPane.leftAnchor="5.0" AnchorPane.rightAnchor="5.0" AnchorPane.topAnchor="5.0">
         <children>
            <Text strokeType="OUTSIDE" strokeWidth="0.0" text="Adding Person Dialog" />
            <HBox alignment="CENTER" prefHeight="50.0" prefWidth="200.0" spacing="10.0">
               <children>
                  <Label alignment="CENTER_RIGHT" minWidth="100.0" text="Id" />
                  <TextField fx:id="tfId" HBox.hgrow="ALWAYS" />
               </children>
               <padding>
                  <Insets right="30.0" />
               </padding>
            </HBox>
            <HBox alignment="CENTER" prefHeight="50.0" prefWidth="200.0" spacing="10.0">
               <children>
                  <Label alignment="CENTER_RIGHT" minWidth="100.0" text="Name" />
                  <TextField fx:id="tfName" HBox.hgrow="ALWAYS" />
               </children>
               <padding>
                  <Insets right="30.0" />
               </padding>
            </HBox>
            <HBox alignment="CENTER" prefHeight="50.0" prefWidth="200.0" spacing="10.0">
               <children>
                  <Label alignment="CENTER_RIGHT" minWidth="100.0" text="Age" />
                  <TextField fx:id="tfAge" HBox.hgrow="ALWAYS" />
               </children>
               <padding>
                  <Insets right="30.0" />
               </padding>
            </HBox>
            <HBox alignment="CENTER_RIGHT">
               <children>
                  <Button mnemonicParsing="false" onAction="#btnAddPersonClicked" text="Add" />
               </children>
               <opaqueInsets>
                  <Insets />
               </opaqueInsets>
               <padding>
                  <Insets right="30.0" />
               </padding>
            </HBox>
         </children>
      </VBox>
   </children>
</AnchorPane>

Person.java

package customdialog;

import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleStringProperty;

public class Person {

    private SimpleIntegerProperty id;
    private SimpleStringProperty name;
    private SimpleIntegerProperty age;

    public Person(int id, String name, int age)  {
        this.id = new SimpleIntegerProperty(id);
        this.name = new SimpleStringProperty(name);
        this.age = new SimpleIntegerProperty(age);
    }

    public int getId() {
        return id.get();
    }

    public void setId(int ID) {
        this.id.set(ID);
    }

    public String getName() {
        return name.get();
    }

    public void setName(String nme) {
        this.name.set(nme);
    }

    public int getAge() {
        return age.get();
    }

    public void setAge(int age) {
        this.age.set(age);
    }

    @Override
    public String toString() {
        return "id: " + id.get() + " - " + "name: " + name.get()+ "age: "+ age.get();
    }

}

Screenshot