I just started Java and getting some GUI with Fx but I get an null pointer exception when trying to replace my scenecontent.
In the main the Login.fxml is loaded without any problem but when I click to the button for switching to another fxml I get the error.
The main:
package application;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.ResourceBundle;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.fxml.JavaFXBuilderFactory;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.layout.AnchorPane;
import javafx.stage.Stage;
public class Main extends Application {
private Stage stage;
#Override
public void start(Stage primaryStage) {
Parent root;
try {
root = FXMLLoader.load(getClass().getResource("Login.fxml"));
} catch (IOException e) {
e.printStackTrace();
return;
}
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.sizeToScene();
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
private void gotoMainView() {
try {
MainViewController profile = (MainViewController) replaceSceneContent("MainView.fxml");
profile.setApp(this);
} catch (Exception ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
void Userlogin()
{
gotoMainView();
}
private void gotoLogin() {
try {
LoginController login = (LoginController) replaceSceneContent("Login.fxml");
login.setApp(this);
} catch (Exception ex) {
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
private Initializable replaceSceneContent(String fxml) throws Exception {
FXMLLoader loader = new FXMLLoader();
InputStream in = Main.class.getResourceAsStream(fxml);
loader.setBuilderFactory(new JavaFXBuilderFactory());
loader.setLocation(Main.class.getResource(fxml));
AnchorPane page;
try {
page = (AnchorPane) loader.load(in);
} finally {
in.close();
}
Scene scene = new Scene(page, 800, 600);
stage.setScene(scene);
stage.sizeToScene();
return (Initializable) loader.getController();
}
}
The Logincontroller class:
package application;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;
public class LoginController extends AnchorPane implements Initializable {
#FXML
static private Button btntext;
#FXML
static private TextField loginusr;
#FXML
static private PasswordField loginpwd;
private Main application;
public void setApp(Main application){
this.application = application;
}
#Override
public void initialize(URL location, ResourceBundle resources) {
btntext.setOnAction(new EventHandler<ActionEvent>() {
#Override public void handle(ActionEvent e) {
System.out.println(loginusr.getText());
System.out.println(loginpwd.getText());
application.Userlogin();
}
});
}
The error occurs at:
application.Userlogin();
Many thanks in advance
The initialize() method is called as soon as the FXML is loaded. Have a look here
Your initialize() is called before setApp(Main application). At this point of time, the application object has not been initialized and is null !
This means the initialize() method is called at
MainViewController profile = (MainViewController) replaceSceneContent("MainView.fxml");
whereas application object which is used inside the initialize() is instantiated after this line, when you are using
profile.setApp(this);
So when you are trying the code application.Userlogin(); inside initalize(), at the time of execution, application is null !
Related
Main Class :
package sample;
import javafx.application.Application;
import javafx.application.Platform;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.stage.Stage;
import java.util.Objects;
public class Main extends Application {
private static Stage primaryStage;
#Override
public void start(Stage primaryStage) throws Exception {
Parent root = FXMLLoader.load(Objects.requireNonNull(getClass().getResource("sample.fxml")));
primaryStage.setTitle("Chess");
primaryStage.getIcons().add(new Image("sample/pieces/chessIcon.jpg"));
primaryStage.setScene(new Scene(root, 700, 600));
primaryStage.setResizable(false);
this.primaryStage = primaryStage;
primaryStage.show();
}
public static void restart() {
Platform.runLater(() -> {
primaryStage.close();
try {
Application.launch(Main.class);
} catch (Exception e) {
e.printStackTrace();
}
});
}
public static void main(String[] args) {
launch(args);
}
}
The Button Class(CheckMatePopUp) from where the application will be relaunched
package sample;
public class CheckMatePopUp implements Initializable {
#FXML
private Button closeBtn;
#FXML
private Label player;
#FXML
private void closeBtn(ActionEvent event){
System.exit(0);
}
#FXML
private void RestartBtn(ActionEvent event){
// Stage stage = (Stage) closeBtn.getScene().getWindow();
// stage.close();
Main.restart();
}
#Override
public void initialize(URL url, ResourceBundle resourceBundle) {
}
}
Getting error : java.lang.IllegalStateException: Application launch must not be called on the JavaFX Application Thread
at javafx.graphics#19/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:173)
at javafx.graphics#19/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:154)
at javafx.graphics#19/javafx.application.Application.launch(Application.java:236)
at sample.Main.lambda$restart$0(Main.java:33)
at javafx.graphics#19/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:457)
at java.base/java.security.AccessController.doPrivileged(AccessController.java:399)
at javafx.graphics#19/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:456)
I have a login page and I'm trying to get a users email that they entered to display on the next page which is their homepage. This is that code:
FXMLLoader loaderNew = new FXMLLoader(getClass().getResource("/sample/view/Dashboard.fxml"));
try {
loaderNew.load();
} catch (IOException e) {
e.printStackTrace();
}
DashboardController dashboardController = loaderNew.getController();
dashboardController.setName(loginEmail.getText().trim());
And this is the method I'm trying to call:
public void setName(String name){
nameLbl.setText(name);
}
I'm getting no errors, it's just not updated the nameLbl and I have no idea why. The logincontroller will go the dashboard successfully, it just won't update the nameLbl.
Here are both full codes.
Login Controller:
package sample.controller;
import java.io.IOException;
import java.net.URL;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.stage.Stage;
import sample.database.DBConnection;
import sample.model.User;
public class LoginController {
#FXML
private ResourceBundle resources;
#FXML
private URL location;
#FXML
private Button loginButton;
#FXML
private TextField loginEmail;
#FXML
private Button createAccountSwitchButton;
#FXML
private Label errorLabel;
#FXML
private PasswordField loginPassword;
private DBConnection dbConnection;
#FXML
void initialize() {
dbConnection = new DBConnection();
loginButton.setOnAction(event-> {
String loginEmailText = loginEmail.getText().trim();
String loginPasswordText = loginPassword.getText().trim();
User user = new User();
user.setEmail(loginEmailText);
user.setPassword(loginPasswordText);
ResultSet userRow = dbConnection.checkForUser(user);
int counter = 0;
try{
while (userRow.next()){
counter++;
}
if (counter==1){
//-------------------Below this line to the next line seems to do nothing-------------------------------------------------------------------
FXMLLoader loaderNew = new FXMLLoader(getClass().getResource("/sample/view/Dashboard.fxml"));
try {
loaderNew.load();
} catch (IOException e) {
e.printStackTrace();
}
DashboardController dashboardController = loaderNew.getController();
dashboardController.setName(loginEmail.getText().trim());
//---------------------------------------------------------------------------------------
loginButton.getScene().getWindow().hide();
FXMLLoader loader = new FXMLLoader();
loader.setLocation(getClass().getResource("/sample/view/Dashboard.fxml"));
try {
loader.load();
} catch (IOException e) {
e.printStackTrace();
}
Parent root = loader.getRoot();
Stage stage = new Stage();
stage.setScene(new Scene(root));
stage.showAndWait();
}else{
errorLabel.setText("Email or Password Incorrect");
}
}catch(SQLException e){
e.printStackTrace();
}
});
}
}
Dashboard controller:
package sample.controller;
//imports here same as above
public class DashboardController {
#FXML
private Label nameLbl;
public void setName(String name){
nameLbl.setText(name);
}
#FXML
void initialize() {
}
}
It seems like my method in Dashboard controller is never being called, why is that? Thanks in advance for any help.
I updated the small segment such that it's only loading one FXML Loader thing and it works now.
loginButton.getScene().getWindow().hide();
FXMLLoader loader = new FXMLLoader(getClass().getResource("/sample/view/Dashboard.fxml"));
try {
loader.load();
} catch (IOException e) {
e.printStackTrace();
}
Parent root = loader.getRoot();
DashboardController dashboardController = loader.getController();
dashboardController.setName(loginEmail.getText().trim());
Stage stage = new Stage();
stage.setScene(new Scene(root));
stage.show();
I'm new to JavaFX and trying build a simple client application that has a root landing stage (rootLayout) with buttons that will allow me to swap out the RootLayout.FXML with a sub FXML. My issue begins when I attempt to load a TreeView within the sub FXML pane. The TreeView is used to load a file directory within this area of the sub-pane.
Thank you!!!
Main
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.layout.BorderPane;
public class MainApp extends Application {
public static Properties configProp;
private Stage primaryStage;
private static BorderPane rootLayout;
/**
* Just a root getter for the controller to use
*/
public static BorderPane getRoot() {
return rootLayout;
}
#Override
public void start(Stage primaryStage) {
this.primaryStage = primaryStage;
initRootLayout();
}
public static void main(String[] args) {
configProp = loadProperties();
launch(args);
}
/***
* Initialize the root layout
* #param args
*/
public void initRootLayout() {
try {
// Load root layout from fxml file.
FXMLLoader loader = new FXMLLoader();
loader.setLocation(MainApp.class.getResource("view/RootLayout.fxml"));
rootLayout = (BorderPane) loader.load();
// Show the scene containing the root layout.
Scene scene = new Scene(rootLayout);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
} catch (IOException e) {
e.printStackTrace();
}
}
}
RootLayoutController
import java.io.IOException;
import einMyQueue.MainApp;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.Alert;
import javafx.scene.control.SplitPane;
import javafx.scene.control.Alert.AlertType;
import javafx.scene.layout.BorderPane;
public class RootLayoutController {
// Reference to the main application
private MainApp mainApp;
/**
* Is called by the main application to give a reference back to itself.
*
* #param mainApp
*/
public void setMainApp(MainApp mainApp) {
this.mainApp = mainApp;
}
/**
* Selects the FAST Scene
*/
#FXML
private void handleFASTSceneSelection() {
try {
SplitPane paneOne = FXMLLoader.load(getClass().getResource("FASTMessageRequest.fxml"));
BorderPane border = MainApp.getRoot();
border.setCenter(paneOne);
} catch (IOException e) {
e.printStackTrace();
}
}
}
Sub-Controller that implements TextView
import java.io.File;
import java.net.URISyntaxException;
import java.net.URL;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.SAXException;
import einMyQueue.MainApp;
import javafx.fxml.FXML;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListView;
import javafx.scene.control.TextArea;
import javafx.scene.control.TreeItem;
import javafx.scene.control.TreeView;
import javafx.stage.DirectoryChooser;
public class FASTMessageRequestController {
private MainApp mainApp;
// FXML Annotations
#FXML private TreeView<String> msgDirTreeView;
#FXML private TextArea msgBodyTextArea;
#FXML private TextArea consoleTextArea;
public void initialize() {
// Using a Tree View
msgDirTreeView = new TreeView<String>();
DirectoryChooser dirChooser = new DirectoryChooser();
URL url = getClass().getResource("../resources/templates");
try {
dirChooser.setInitialDirectory(new File(url.toURI()));
File file = dirChooser.getInitialDirectory();
msgDirTreeView.setRoot(getNodesForDirectory(file));
} catch (URISyntaxException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public TreeItem<String> getNodesForDirectory(File directory) {
TreeItem<String> msgDirRoot = new TreeItem<String>(directory.getName());
for(File iFile : directory.listFiles()) {
System.out.println("Loading " + iFile.getName());
if(iFile.isDirectory()) {
msgDirRoot.getChildren().add(getNodesForDirectory(iFile));
} else {
msgDirRoot.getChildren().add(new TreeItem<String>(iFile.getName()));
}
}
return msgDirRoot;
}
/***
* Name: setMainApp
* Purpose: Is called by the main application to give a reference back to itself.
*
* #param mainApp
*/
public void setMainApp(MainApp mainApp) {
// Is called by the main application to give a reference back to itself.
this.mainApp = mainApp;
}
}
I'm writing a simple JavaFX application that has three Stages: Login, Register (Anmeldung) and Welcome (Anwendung). Sorry for the German namings!
I have created each Stage and it's Scene in an App class and the handling events in a Controller class and the designs in fxml files. I need to implement a MainApp class which has to manage the communication between Login, Anmeldung and Anwendung windows.
The MainApp should initially launch a Login window and then in there if the checkbox is selected, the MainApp should be notified and order the launch of Anmeldung window. After successful registration, the MainApp should close the Anmeldung window and show the Login window again. There, when user logs in, the MainApp should again close the Login window and order a launch for Anwendung window.
I have done the transition between Login and Anmeldung windows by modifying the LoginController, which shouldn't be done there and has to be accomplished via the MainApp.
Additionally the task wants the whole thing to be done with only one launch(args).
LoginController.java:
package controller;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.CheckBox;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.stage.Modality;
import javafx.stage.Stage;
import resources.Benutzer;
public class LoginController {
// private static MainApp mainApp;
#FXML
public TextField textFieldUserId;
#FXML
public PasswordField passwordFieldPasswort;
#FXML
public CheckBox checkBoxNeuAnmeldung;
#FXML
public Button buttonEinloggen;
private boolean neuAnmeldung = false;
// public void setCallBack(MainApp mainApp) {
// LoginController.mainApp = mainApp;
// }
#FXML
public void handleButtonEinloggenAction(ActionEvent event) throws Exception {
// Stage stage = (Stage) buttonEinloggen.getScene().getWindow();
if (neuAnmeldung == false) {
Benutzer benutzer = new Benutzer(textFieldUserId.getText(),
passwordFieldPasswort.getText());
Parent anwendungsScene = FXMLLoader
.load(getClass().getResource("/design/Anwendung.fxml"));
Stage anwendungsStage = new Stage();
((Node) (event.getSource())).getScene().getWindow().hide();
anwendungsStage.setScene(new Scene(anwendungsScene));
anwendungsStage.setTitle("Anmeldung");
anwendungsStage.show();
System.out.println(benutzer);
}
// stage.close();
System.out.println("Eingeloggt!");
}
#FXML
public void handleCheckBoxNeuAnmeldungAction(ActionEvent event)
throws Exception {
if (checkBoxNeuAnmeldung.isSelected()) {
neuAnmeldung = true;
Parent anmeldungsScene = FXMLLoader
.load(getClass().getResource("/design/Anmeldung.fxml"));
Stage anmeldungsStage = new Stage();
anmeldungsStage.initModality(Modality.WINDOW_MODAL);
anmeldungsStage
.initOwner(((Node) (event.getSource())).getScene().getWindow());
anmeldungsStage.setScene(new Scene(anmeldungsScene));
anmeldungsStage.setTitle("Anmeldung");
anmeldungsStage.show();
} else
neuAnmeldung = false;
System.out.println("Neu-Anmeldung? " + neuAnmeldung);
}
}
AnmeldungsController.java:
package controller;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
import javafx.scene.control.PasswordField;
import javafx.scene.control.TextField;
import javafx.stage.Stage;
import resources.Benutzer;
public class AnmeldungsController {
// private static MainApp mainApp;
#FXML
public TextField textFieldUserId;
#FXML
public PasswordField passwordFieldPasswort;
#FXML
public PasswordField passwordFieldWiederholung;
#FXML
public Button buttonAnmelden;
// public void setCallBack(MainApp mainApp) {
// AnmeldungsController.mainApp = mainApp;
// }
#FXML
public void handleButtonAnmeldenAction(ActionEvent event) {
Stage stage = (Stage) buttonAnmelden.getScene().getWindow();
if (passwordFieldPasswort.getText()
.equals(passwordFieldWiederholung.getText())) {
Benutzer benutzer = new Benutzer(textFieldUserId.getText(),
passwordFieldPasswort.getText());
System.out.println(benutzer);
System.out.println("Angemeldet!");
stage.close();
} else {
textFieldUserId.setText("Passwörter stimmen nicht überein!");
System.out.println("Passwörter stimmen nicht überein!");
System.out.println(passwordFieldPasswort.getText() + " != "
+ passwordFieldWiederholung.getText());
}
}
}
AnwendungsController.java:
package controller;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.scene.control.Button;
import javafx.stage.Stage;
public class AnwendungsController {
// private static MainApp mainApp;
#FXML
public Button buttonSchliessen;
// public void setCallBack(MainApp mainApp) {
// AnwendungsController.mainApp = mainApp;
// }
#FXML
public void handleButtonAbbrechenAction(ActionEvent event) {
Stage stage = (Stage) buttonSchliessen.getScene().getWindow();
stage.close();
System.out.println("Fenster Geschlossen!");
}
}
MainApp.java:
package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class MainApp extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader loader = new FXMLLoader(
getClass().getResource("/design/Login.fxml"));
Parent root = loader.load();
primaryStage.setTitle("Benutzerverwaltung");
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
}
Of course the other aspects of the program like Exceptions and creating/reading/deleting users etc is out of the scope of this question!
Here is the basic idea that should get you started:
public class LoginController {
private final ReadOnlyBooleanWrapper loggedIn = new ReadOnlyBooleanWrapper();
public ReadOnlyBooleanProperty loggedInProperty() {
return loggedIn.getReadOnlyProperty() ;
}
public final boolean isLoggedIn() {
return loggedInProperty().get();
}
#FXML
public TextField textFieldUserId;
#FXML
public PasswordField passwordFieldPasswort;
#FXML
public CheckBox checkBoxNeuAnmeldung;
#FXML
public Button buttonEinloggen;
private boolean neuAnmeldung = false;
#FXML
public void handleButtonEinloggenAction(ActionEvent event) throws Exception {
// assuming you verify the login credentials...
loggedIn.set(true);
System.out.println("Eingeloggt!");
}
}
and now in your MainApp you can do:
package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class MainApp extends Application {
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) throws Exception {
FXMLLoader loader = new FXMLLoader(
getClass().getResource("/design/Login.fxml"));
Parent root = loader.load();
LoginController loginController = loader.getController();
loginController.loggedInProperty().addListener((obs, wasLoggedIn, isNowLoggedIn) -> {
if (isNowLoggedIn) {
// user is now logged in, show welcome screen...
}
});
primaryStage.setTitle("Benutzerverwaltung");
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
}
I have a problem with my basic encrypter application. I want to generate an error window if someone type a string in the keyTextField. And also an event to close the error window using OK Button(Window graphic is loading from fxml file)
I've tried making it as shown below, but without success, i was also using close() method. What are best methods to deal with application control? I am using only MainController and i think it is not good idea. Thank you in advance
`package pl.gumisok.cipherController;
import java.io.IOException;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TextArea;
import javafx.scene.control.TextField;
import javafx.stage.Stage;
import pl.gumisok.cipherMain.CipherManager;
public class MainController implements Initializable {
CipherManager cipher;
#FXML
private ContentPaneController contentPaneController;
#FXML
private ControlPaneController controlPaneController;
#Override
public void initialize(URL arg0, ResourceBundle arg1) {
// TODO Auto-generated method stub
System.out.println(contentPaneController);
System.out.println(controlPaneController);
Button encryptButton = controlPaneController.getEncryptButton();
Button decryptButton = controlPaneController.getDecryptButton();
Button okButton = controlPaneController.getOkButton();
TextArea cleanTextArea = contentPaneController.getCleanTextArea();
TextArea cryptTextArea = contentPaneController.getCryptTextArea();
TextField keyTextField = controlPaneController.getKeyTextField();
encryptButton.setOnAction(new EventHandler<ActionEvent>() {
#Override
public void handle(ActionEvent event) {
String wiadomosc = cleanTextArea.getText();
System.out.println(wiadomosc);
try {
int key = Integer.parseInt(keyTextField.getText());
System.out.println(key);
} catch (NumberFormatException e) {
System.out.println(e);
FXMLLoader fxmlLoader = new FXMLLoader(getClass()
.getClassLoader().getResource(
"pl/gumisok/cipherView/Error.fxml"));
Parent root;
try {
root = fxmlLoader.load();
Stage sstage = new Stage();
sstage.setOpacity(1);
sstage.setTitle("Error");
sstage.setScene(new Scene(root));
sstage.show();
okButton.setOnAction(x->sstage.hide());
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
});
}
}`
your application layer is not good.
you need bind the button action in fxml file to a controller.
Maybe something like this:
Error.fxml:
<AnchorPane xmlns="http://javafx.com/javafx/8"
xmlns:fx="http://javafx.com/fxml/1"
fx:controller="controllers.ErrorController">
<children>
<Label text="ERROR!" />
<Button text="close" onAction="#hide" layoutY="15"/>
</children>
</AnchorPane>
ErrorController.java:
public class ErrorController {
private static Stage stage;
private static Parent root;
public ErrorController(){}
public ErrorController(Window owner) throws IOException {
if (root == null)
root = FXMLLoader.load(ClassLoader
.getSystemResource("views/Error.fxml"));
if (stage == null)
stage = new Stage();
//stage.initModality(Modality.WINDOW_MODAL);
stage.initOwner(owner);
stage.setTitle("Error");
stage.setScene(new Scene(root));
}
public void show() {
stage.show();
}
public #FXML void hide() {
stage.hide();
}
}
And then use it
...
error = new ErrorController(node.getScene().getWindow());
...
try {
int key = Integer.parseInt(keyTextField.getText());
System.out.println(key);
} catch (NumberFormatException e) {
error.show();
}
I hope, I understand the question correct,
here is an example how to create an alert dialog
Alert alert = new Alert(AlertType.INFORMATION);
alert.setTitle("Information Dialog");
alert.setHeaderText(null);
alert.setContentText("I have a great message for you!");
alert.showAndWait();