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How to transfer string between methods (Java)

Essentially, I'm trying to collect data for a string and use it in another method. Whatever I've tried hasn't seemed to work. Please check out my code and tell me what to do.
I've tried to declare the string as a public string, but since it is in a method I can't.
My goal is to transfer the string "application_1" to button3's setOnAction method.
#Override
public void start(Stage primaryStage) throws Exception {
window = primaryStage;
window.setTitle("myDesktop");
window.setOnCloseRequest(e -> closeProgram());
button = new Button("Setup MyDesktop");
button3 = new Button("Start Test Application");
button2 = new Button("Choose Wheel Applications");
button2.setOnAction(e -> {
JFileChooser jfc = new JFileChooser();
jfc.showDialog(null, "Please select a file.");
jfc.setVisible(true);
File filename = jfc.getSelectedFile();
String application_1 = filename.getName();
if (application_1.endsWith(".exe")) {
System.out.println("File successfully chosen!");
} else {
System.out.println("File is not an application!");
System.out.println("Please choose another file!");
System.out.println("Issue Alert Box here...");
}
if (application_1 == null) {
System.out.println("No file selected!");
}
});
button.setOnAction(e -> {
AlertBox.display("Alert", "Save file?");
});
button3.setOnAction(e -> {
Runtime runtime = Runtime.getRuntime();
try {
Process process = runtime.exec("name_of_file");
} catch (IOException e1) {
e1.printStackTrace();
}
});
I want the string to be able to be used by the code
button3.setOnAction(e -> {
// code
});

Should work:
#Override
public void start(Stage primaryStage) throws Exception {
window = primaryStage;
window.setTitle("myDesktop");
window.setOnCloseRequest(e -> closeProgram());
String application_1 = "";
button = new Button("Setup MyDesktop");
button3 = new Button("Start Test Application");
button2 = new Button("Choose Wheel Applications");
button2.setOnAction(e -> {
JFileChooser jfc = new JFileChooser();
jfc.showDialog(null, "Please select a file.");
jfc.setVisible(true);
File filename = jfc.getSelectedFile();
application_1 = filename.getName();
if (application_1.endsWith(".exe")) {
System.out.println("File successfully chosen!");
} else {
System.out.println("File is not an application!");
System.out.println("Please choose another file!");
System.out.println("Issue Alert Box here...");
}
if (application_1 == null) {
System.out.println("No file selected!");
}
});
button.setOnAction(e -> {
AlertBox.display("Alert", "Save file?");
});
button3.setOnAction(e -> {
Runtime runtime = Runtime.getRuntime();
System.out.println(application_1); //here you can use the variable
try {
Process process = runtime.exec("name_of_file");
} catch (IOException e1) {
e1.printStackTrace();
}
});

Since you don't have control over the actual event that's created when the button is hit you cannot pass it directly (well, maybe you could add a tag to the button or something similar - I never used javafx).
But nothing prevents you from introducing an object-level variable to hold your string(s).
class YourClass {
private String myString = "";
public void start(Stage primaryStage) throws Exception {
// ...
button2.setOnAction(e -> {
this.myString = "application_1";
});
// ...
button3.setOnAction(e -> {
System.out.println(this.myString);
});
}
}
Alternatively, if your variable is final or effectively final you can just use it in your anonymous function:
class YourClass {
public void start(Stage primaryStage) throws Exception {
// ...
final String myString = "application_1";
// ...
button3.setOnAction(e -> {
System.out.println(myString);
});
}
}

Why can't I use setText() under Button event?

So I am remaking my kinda complex console program to GUI. However, I am very unexperienced JavaFX user.
Label cityNameLabel = (Label) scene.lookup("#cityNameLabel");
cityNameLabel.setText("No text");
Button startButton = (Button) scene.lookup("#startButton");
Here I have my Label successfully initiated. At this moment I can still use cityNameLabel.setText(); and it is gonna work.
This continues:
startButton.setOnAction(e -> {
String enteredUrl = linkField.getText();
if(isValidUrl(enteredUrl)) {
try {
cityNameLabel.setText("Test");
doJob(enteredUrl, cityNameLabel);
} catch (IOException e1) {
e1.printStackTrace();
} catch (InterruptedException e1) {
e1.printStackTrace();
}
}.........
When I try to change the label here it won't happen. What I actually need to do is to reference the cityNamelLabel to doJob() method and I want to doJob() method to change it (once it finds the name of the city).
Can anyone give a me a solution that would allow me to do what I want to do? (changing it afterwards from doJob();). Thank you!
EDIT: Here I post my attemp of minimal version. I hope it is enough
package net.maty;
public class Katastr extends Application {
final String programName = "KatastRED";
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage mainStage) throws Exception {
try {
mainStage.setTitle(programName);
mainStage.setResizable(false);
BorderPane root = (BorderPane)FXMLLoader.load(getClass().getResource("Katastr.fxml"));
Scene scene = new Scene(root,800,500);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
ChoiceBox threadNumberBox = (ChoiceBox) scene.lookup("#threadNumberBox");
threadNumberBox.getSelectionModel().select(5);
TextField linkField = (TextField) scene.lookup("#linkField");
//debug
linkField.setText("https://regiony.kurzy.cz/katastr/stary-kolin/objekty?strana=");
//
Text cityNameText = (Text) scene.lookup("#cityNameText");
Button startButton = (Button) scene.lookup("#startButton");
//HERE IS THE THING. EVERYTHING WORKS WELL EXCEPT THE FACT I CANT CHANGE CITYNAMETEXT
startButton.setOnAction(e -> {
String enteredUrl = linkField.getText();
if(isValidUrl(enteredUrl)) {
try {
cityNameText.setText("Example that will not show because it doesnt work.");
doJob(enteredUrl, cityNameText);
} catch (IOException e1) {
e1.printStackTrace();
} catch (InterruptedException e1) {
e1.printStackTrace();
}
}
else {
Alert alert = new Alert(AlertType.ERROR);
alert.setTitle("Chyba!");
alert.setHeaderText(null);
alert.setContentText("Chybně zadané URL!");
alert.showAndWait();
}
});
mainStage.setScene(scene);
mainStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
public static void doJob(String validatedUrl, Text cityNameText) throws IOException, InterruptedException {
Scanner in = new Scanner(System.in);
String url = validatedUrl;
String cityName = getCityName(url);
cityNameText.setText(cityName);
List<String> parcelLinks = getParcelLinks(url);.....
}
public static List<String> getParcelLinks(String url) throws IOException{
}
public static List<String> getAdressesFromPage(Document doc) {
}
public static List<String> createParcelUrls(List<String> links) throws IOException {
}
public static boolean isValidUrl(String url) {
}
public static String getCityName(String url) throws IOException {
}
}

JavaFX SetOnCloseRequest() closing all screens

In my application I have multiple .fxml files. When I set a screen in my application, I also set the SetOnCloseRequest() method. For some screens is the code in that method just to switch to another screen. For example: When I have my Create Bank screen open and I press the close button, I want to switch back to my Manage Banks screen. But when I press the close button, it seems to switch the screens correctly, but very shortly after it closes the Manage Banks screen for some reason and the application dont stops running. So I cant do anything after that, because I don't have any GUI.
Does someone knows how to make sure that the Manage Banks screens does not close?
Here is my main class with theSetOnCloseRequest() method:
public class ClientMain extends Application {
public static String screenCreateBankId = "createBank";
public static String screenCreateBankFile = "Screens/createBank.fxml";
public static String screenCreateBankAccountId = "createBankAccount";
public static String screenCreateBankAccountFile = "Screens/createBankAccount.fxml";
public static String screenLoginId = "login";
public static String screenLoginFile = "Screens/login.fxml";
public static String screenManageBanksId = "manageBanks";
public static String screenManageBanksFile = "Screens/manageBanks.fxml";
private static Stage primaryStage;
private static ScreensController mainContainer;
public static void main(String[] args) {
launch(args);
}
#Override
public void start(Stage primaryStage) {
ClientMain.primaryStage = primaryStage;
mainContainer = new ScreensController();
mainContainer.loadScreen(ClientMain.screenCreateBankId, ClientMain.screenCreateBankFile);
mainContainer.loadScreen(ClientMain.screenLoginId, ClientMain.screenLoginFile);
mainContainer.loadScreen(ClientMain.screenManageBanksId, ClientMain.screenManageBanksFile);
mainContainer.setScreen(ClientMain.screenLoginId);
Group root = new Group();
root.getChildren().addAll(mainContainer);
primaryStage.setResizable(false);
primaryStage.getIcons().add(new Image("file:assets/ideal_logo.jpg"));
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
public static void setProperties(String name){
primaryStage.sizeToScene();
primaryStage.centerOnScreen();
switch (name){
case "createBank":
primaryStage.setTitle("Create Bank");
primaryStage.setOnCloseRequest(event -> mainContainer.setScreen(screenManageBanksId));
break;
case "login":
primaryStage.setTitle("Login");
primaryStage.setOnCloseRequest(event -> System.exit(0));
break;
case "manageBanks":
primaryStage.setTitle("Manage Banks");
primaryStage.setOnCloseRequest(event -> mainContainer.getManageBanksController().logoutAdmin());
break;
}
}
}
And here is my ScreensController class:
public class ScreensController extends StackPane {
private HashMap<String, Node> screens = new HashMap<>();
private Client client;
private NewTransactionController newTransactionController;
private BankAccountController bankAccountController;
private ManageBanksController manageBanksController;
public Client getClient() {
return this.client;
}
public NewTransactionController getNewTransactionController() {
return this.newTransactionController;
}
public BankAccountController getBankAccountController() {
return this.bankAccountController;
}
public ManageBanksController getManageBanksController() {
return this.manageBanksController;
}
public ScreensController() {
try {
this.client = new Client();
System.out.println("Client: Client created");
} catch (RemoteException e) {
System.out.println("Client: Cannot create Client");
System.out.println("Client: RemoteException: " + e.getMessage());
System.exit(0);
}
}
public void addScreen(String name, Node screen) {
screens.put(name, screen);
}
public void loadScreen(String name, String resource) {
try {
FXMLLoader myLoader = new FXMLLoader(getClass().getResource(resource));
Parent loadScreen = myLoader.load();
IControllers myScreenController = myLoader.getController();
if (myScreenController instanceof NewTransactionController) {
this.newTransactionController = (NewTransactionController) myScreenController;
} else if (myScreenController instanceof BankAccountController) {
this.bankAccountController = (BankAccountController) myScreenController;
} else if (myScreenController instanceof ManageBanksController) {
this.manageBanksController = (ManageBanksController) myScreenController;
}
myScreenController.setScreenParent(this);
addScreen(name, loadScreen);
} catch (Exception e) {
e.printStackTrace();
}
}
public void setScreen(final String name) {
if (screens.get(name) != null) {
if (!getChildren().isEmpty()) {
getChildren().remove(0);
getChildren().add(0, screens.get(name));
ClientMain.setProperties(name);
} else {
//First time start up
getChildren().add(screens.get(name));
ClientMain.setProperties(name);
}
} else {
System.out.println("Screen hasn't been loaded!!!");
}
}
}

try this
primaryStage.setOnCloseRequest(event -> {
event.consume();
mainContainer.setScreen(screenManageBanksId);
});
...
primaryStage.setOnCloseRequest(event -> {
event.consume();
mainContainer.getManageBanksController().logoutAdmin();
});

Why do JButtons that open webpages only work the first time one is clicked and then get deactivated?

I have a set of JButtons, each of which opens a separate YouTube video webpage. When first running the program, I can click on any ONE button and get the video page. When I try to get another video page with a button click, it doesn't work - in fact, all the buttons are deactivated. This is the case whether or not I close the video webpage.
How can I keep all the buttons activated? Thanks in advance.
Here's the code for reference. The button links and tags are populated from a text file.
//import statements
public class VideoRecord extends JFrame {
private File videoRecordFile;
public VideoRecord() throws FileNotFoundException {
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
setLayout(new GridLayout(2,2));
setSize(new Dimension(500, 500));
videoRecordFile = new File("videorecord.txt");
getButtons();
pack();
}
public void getButtons() throws FileNotFoundException {
Scanner input = new Scanner(videoRecordFile);
while (input.hasNextLine()) {
Scanner lineInput = new Scanner(input.nextLine());
while (lineInput.hasNext()) {
final String urlString = lineInput.next();
String buttonText = lineInput.next();
JButton btn = new JButton(buttonText);
add(btn);
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
URL videoURL = new URL(urlString);
URLConnection videoConnection = videoURL.openConnection();
videoConnection.connect();
openWebpage(videoURL);
}
catch (MalformedURLException mue) {}
catch (IOException ioe) {}
setEnabled(false);
}
});
}
}
}
public static void openWebpage(URI uri) {
Desktop desktop = Desktop.isDesktopSupported() ? Desktop.getDesktop() : null;
if (desktop != null && desktop.isSupported(Desktop.Action.BROWSE)) {
try {
desktop.browse(uri);
} catch (Exception e) {
e.printStackTrace();
}
}
}
public static void openWebpage(URL url) {
try {
openWebpage(url.toURI());
} catch (URISyntaxException e) {
e.printStackTrace();
}
}
public static void main(String[] args) throws FileNotFoundException {
VideoRecord vr = new VideoRecord();
}
}

Take a second to look at you code...
btn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
try {
URL videoURL = new URL(urlString);
URLConnection videoConnection = videoURL.openConnection();
videoConnection.connect();
openWebpage(videoURL);
}
catch (MalformedURLException mue) {}
catch (IOException ioe) {}
setEnabled(false);
}
});
When you click a button you call setEnabled(false);...
This has actually disable the frame, not the button that was clicked...
Try using ((JButton)e.getSource()).setEnabled(false) instead
Don't throw away you Exceptions blindly, they provide important and useful information that can help solve problems

How to make custom Java/JavaFX console?

It's necessary to make a custom console. I have the following code:
public class Console extends OutputStream{
private Console(ResourceBundle resourceBundle) throws IOException {
FXMLLoader loader = new FXMLLoader(this.getClass().getResource("Console.fxml"), resourceBundle);
controller = loader.getController();
Scene scene = new Scene((Parent) loader.load());
stage = new Stage();
stage.setScene(scene);
show();
}
#Override
public void write(int b) throws IOException {
controller.append(b);
}
public static Console getInstance(ResourceBundle resourceBundle) {
if (console == null) {
try {
console = new Console(resourceBundle);
} catch (IOException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
}
return console;
}
public void show() {
stage.show();
}
private static Console console = null;
private ConsoleController controller;
private Stage stage;
}
controller file:
public class ConsoleController implements Initializable {
#Override
public void initialize(URL url, ResourceBundle resourceBundle) {
}
#FXML
public void append(int i) {
textArea.appendText(String.valueOf((char) i));
}
#FXML
private TextArea textArea;
}
And all these are called from the 'start()':
#Override
public void start(Stage primaryStage) throws IOException {
...
System.setErr(new PrintStream(Console.getInstance(rb)));
}
During the exception nothing is printed in the textArea of the Console.fxml, but the following exception is thrown:
Exception in thread "JavaFX Application Thread"
Exception: java.lang.NullPointerException thrown from the UncaughtExceptionHandler in thread "JavaFX Application Thread"
What am I doing wrong?
------EDIT--------
After understanding that it's necessary to use several threads I have the following code:
public class Console{
private Console(ResourceBundle resourceBundle) throws IOException {
FXMLLoader loader = new FXMLLoader(this.getClass().getResource("Console.fxml"), resourceBundle);
Parent root = (Parent) loader.load();
controller = loader.getController();
Scene scene = new Scene(root);
stage = new Stage();
stage.setScene(scene);
show();
if (errorOutputThread != null) {
errorOutputThread.interrupt();
try {
errorOutputThread.join();
} catch (InterruptedException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
errorOutputThread = null;
}
if (outOutputThread != null) {
outOutputThread.interrupt();
try {
outOutputThread.join();
} catch (InterruptedException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
outOutputThread = null;
}
System.err.flush();
System.out.flush();
outPipedInputStream = new PipedInputStream();
outPipedOutputStream = new PipedOutputStream(outPipedInputStream);
System.setOut(new PrintStream(outPipedOutputStream));
errorPipedInputStream = new PipedInputStream();
errorPipedOutputStream = new PipedOutputStream(errorPipedInputStream);
System.setErr(new PrintStream(errorPipedOutputStream));
outOutputThread = new Thread(new ConsoleStream(outPipedInputStream, "OUT"));
outOutputThread.setDaemon(true);
outOutputThread.start();
errorOutputThread = new Thread(new ConsoleStream(errorPipedInputStream, "ERROR"));
errorOutputThread.setDaemon(true);
errorOutputThread.start();
controller.appendText("Start Console");
}
public static Console getInstance(ResourceBundle resourceBundle) {
if (console == null) {
try {
console = new Console(resourceBundle);
} catch (IOException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
}
return console;
}
public void show() {
stage.show();
}
private class ConsoleStream implements Runnable {
private ConsoleStream(InputStream in, String type) {
inputStream = in;
this.type = type;
}
public void run() {
try {
InputStreamReader is = new InputStreamReader(inputStream);
BufferedReader br = new BufferedReader(is);
String read = null;
read = br.readLine();
while(read != null) {
controller.appendText(read + "\n");
read = br.readLine();
}
} catch (IOException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
controller.appendText("Thread" + type + "started");
}
private final InputStream inputStream;
private String type;
}
private static Console console = null;
private ConsoleController controller;
private Stage stage;
private PrintStream printStream;
private PipedOutputStream customPipedOutputStream;
private PipedOutputStream errorPipedOutputStream;
private PipedOutputStream outPipedOutputStream;
private PipedInputStream customPipedInputStream;
private PipedInputStream errorPipedInputStream;
private PipedInputStream outPipedInputStream;
private Thread customOutputThread;
private Thread outOutputThread;
private Thread errorOutputThread;
}
But the result is only: "Start Console", there are no results of controller.appendText("Thread" + type + "started"); so it seems that this threads don't start. But why?

I think you have to load the form before you can get the controller instance
FXMLLoader loader = new FXMLLoader(this.getClass().getResource("Console.fxml"),resourceBundle);
Parent p = (Parent) loader.load()
controller = loader.getController();
Scene scene = new Scene(p);