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Why is my boolean value preemptively being returned?

I am working on a login validator and have a class that checks username and password validity. After checking, a boolean variable (isValidLoginCredentials) is updated in the LoginProxy class, which can be fetched by a get method and used for another purpose. However, the value that is returned by the get method is always the default value that I assigned to isValidLoginCredentials when the class was created. I think the issue is that I am calling the getter method in main() before I have a chance to update isValidLoginCredentials, but I don't understand what changes I should make to stop this. Here is the relevant part of the class and main program.
public class LoginProxy implements ActionListener
{
private JLabel usernameLabel;
private JTextField usernameText;
private JLabel passwordLabel;
private JPasswordField passwordText;
private JButton loginButton;
private boolean isValidLoginCredentials = false;
public void createLogin()
{
/*Here was code irrelevant to the problem I removed*/
loginButton.addActionListener(new LoginProxy());
loginButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
String user = usernameText.getText();//get the username
String pass = passwordText.getText();//get the password
String credentials = user +":"+pass;//creates the string I compare to other valid
//credentials
ConcreteLoginValidator validator = new ConcreteLoginValidator(credentials);
try
{
isValidLoginCredentials = validator.checkLogin();
System.out.println("The credentials are "+isValidLoginCredentials);
}
catch (FileNotFoundException e1)
{
e1.printStackTrace();
}
}
});
}
public void actionPerformed(ActionEvent e)
{
// TODO Auto-generated method stub
}
public boolean getValidity()
{
return isValidLoginCredentials;
}
And here is the main method
public static void main(String[] args)
{
boolean isValidLogin = false;
LoginProxy proxy = new LoginProxy();
proxy.createLogin();
isValidLogin = proxy.getValidity();
if(isValidLogin == true)
{
JFrame frame = MainUI.getInstance();
frame.setSize(900, 600);
frame.pack();
frame.setVisible(true);
}
}
What should I add so that isValidLogin=proxy.getValidity(); returns a value only after I have already entered and checked whether the login credentials are correct?

Going straight to the point, a quick fix is to put the code below:
if(isValidLoginCredentials) {
JFrame frame = MainUI.getInstance();
frame.setSize(900, 600);
frame.pack();
frame.setVisible(true);
}
After this part:
System.out.println("The credentials are "+isValidLoginCredentials);
The code you call on createLogin() just sets the action listener to the button in the UI, hence the code will be executed just when you click on the button.
On the top of that, when you open a window, it starts a separated thread. I don't know the rest of the code, but assuming that when you instantiate the LoginProxy, it opens the login window. But the way you wrote, it will open the window and check the isValidLogin straight away (it doesn't wait you to click the button).
If you want to prove that, you can simply put a System.out.println before and after the proxy.createLogin(). You will realise that both lines will be reached while the UI is rendered.

Using a modal dialog that blocks until it is closed.
Very simplified example:
public class Dialog { // LoginProxy in questions code
private String value = null;
public void show(Window owner) {
var dialog = new JDialog(owner, JDialog.DEFAULT_MODALITY_TYPE);
var field = new JTextField(40);
var okButton = new JButton("OK");
okButton.addActionListener(ev -> {
value = field.getText();
dialog.dispose();
});
var panel = new JPanel();
panel.add(field);
panel.add(okButton);
dialog.add(panel);
dialog.pack();
dialog.setLocationRelativeTo(owner);
dialog.setVisible(true); // this will be blocked until JDialog is closed
}
public String getValue() {
return value;
}
}
called like
public static void main(String[] args) {
var dialog = new Dialog();
dialog.show(null);
System.out.println(dialog.getValue()); // check if valid and open JFrame in questions code
}
Advantage of this solution IMHO: the dialog class (LoginProxy) does not need to know about the main class and main JFrame. It has a clear single function: ask for user input.
the dialog creation is even easier using JOptionPane

In order to guarantee reading a value written in another thread, you must make the field volatile:
private volatile boolean isValidLoginCredentials;
You must also wait until the other completes before reading it. That aspect I leave to the reader.

How can I set up a JFrame button to open another JFrame, and then receive information once the second jframe is closed?

This is part of a project for school, and I'm stuck and need someone to bounce ideas off of. I have a game where there is an option to sign up or sign in for a machine-local game so a record can be kept of the person's scores. The game is run from a base GUI JFrame, and I want to make buttons to bring up secondary windows for the person to sign in or sign up, before closing out of them. I need to pass the validated username back to the initial GUI/game class so I can store it for the following game so the game score can be added under that user. I just need to pass the username back and I'm not sure how to go about it. This is the main GUI code up to where I'm having my issue:
public class MathFactsGUI extends JFrame
{
// instance variables
private JTextField problemJTextField, answerJTextField;
private JLabel equalJLabel;
private JButton additionJButton, multiplicationJButton;
private JButton signupJButton, signinJButton;
private JButton submitJButton;
private JLabel scoreJLabel,resultJLabel;
//private JButton reviewButton;
private String username;
private Userbase userbase;
private JLabel introJLabel;
Quiz quiz;
/**
* Constructor for objects of class MathFactsGUI
*/
public MathFactsGUI()
{
super("Math Facts Quiz");
userbase = Userbase.getUserbase();
username = "guest";
/* code here has been removed to be abbreviated */
// Action listener for buttons
additionJButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
quiz = new Quiz('+');
problemJTextField.setText(quiz.getCurrentProblem());
additionJButton.setEnabled(false);
multiplicationJButton.setEnabled(false);
signupJButton.setEnabled(false);
signinJButton.setEnabled(false);
}
});
multiplicationJButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
quiz = new Quiz('x');
problemJTextField.setText(quiz.getCurrentProblem());
additionJButton.setEnabled(false);
multiplicationJButton.setEnabled(false);
signupJButton.setEnabled(false);
signinJButton.setEnabled(false);
}
});
signinJButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
JDialo
}
});
signupJButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
MathFactsSignUpGUI signUpGUI = new MathFactsSignUpGUI();
gui.setVisible(true);
}
});
}
This is the JFrame I wrote for the sign-up button:
public class MathFactsSignUpGUI extends JDialog {
private JTextField usernameJTextField, userPassJTextField, userFirstNameJTextField;
private JLabel usernameJLabel, userPassJLabel, userFirstNameJLabel;
private JButton submitJButton;
private String username;
private String userPass;
private String userFirstName;
public MathFactsSignUpGUI(){
usernameJLabel = new JLabel("Username:");
usernameJTextField = new JTextField();
userPassJLabel = new JLabel("Password:");
userPassJTextField = new JTextField();
userFirstNameJLabel = new JLabel("Player First Name:");
userFirstNameJTextField = new JTextField();
Box usernameBox = Box.createHorizontalBox();
usernameBox.add(usernameJLabel);
usernameBox.add(usernameJTextField);
Box userPassBox = Box.createHorizontalBox();
userPassBox.add(userPassJLabel);
userPassBox.add(userPassJTextField);
Box userFirstBox = Box.createHorizontalBox();
userFirstBox.add(userFirstNameJLabel);
userFirstBox.add(userFirstNameJTextField);
submitJButton = new JButton("Submit");
submitJButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
username = usernameJTextField.getText();
userPass = userPassJTextField.getText();
userFirstName = userFirstNameJTextField.getText();
if (!checkValid(username) || !checkValid(userPass) || !checkValid(userFirstName)){
JOptionPane.showMessageDialog(null, "All fields must have values.");
} else if (Userbase.getUserbase().userExist(username)==true){
JOptionPane.showMessageDialog(null, "Username is taken, please choose another.");
} else {
Userbase.getUserbase().addUser(username, new User(username, userPass, userFirstName));
MathFactsGUI.setUsername(username);
}
}
});
JPanel mfSignUp = new JPanel()
mfSignUp.setLayout(new GridLayout(0,1));
mfSignUp.add(usernameBox);
mfSignUp.add(userPassBox);
mfSignUp.add(userFirstBox);
mfSignUp.add(submitJButton);
}
public String signIn(){
return username;
}
public boolean checkValid(String a){
if (a == null || a.length() == 0){
return false;
} else {
return true;
}
}
}```
I was thinking of implementing a WindowListener action for when the sign-up/sign-in frames close, but I'm not sure that will work. I was also looking into JDialog, but I'm not sure if it has the layout/text verification properties I need.

Use a JOptionPane. It will simplify your layout without the need for creating a separate JFrame and easily pass values back to wherever it was called from. You can then make it check for valid username when you click OK.
Try this site. It gives a good rundown with example images

First you need to understand that this is an object, so you can create some global variables which will contains this information(username,password,Nickname), i recommend to pull info from MathFactsSignUpGUI by using ScheduledExecutorService. It will pull info from this sign up gui in every 100ms, than it will destroy itself, here is an example:
MathFactsSignUpGUI su = new MathFactsSignUpGUI ();
su.setVisible(true);
ScheduledExecutorService service = Executors.newSingleThreadScheduledExecutor();
service.schedule(new Runnable(){
public void run(){
if(!su.username.isEmpty() && !su.userPass.isEmpty() && !su.userFirstName.isEmpty() ){
if(su.isLogin){ //if player is loggining
//do something here
}else{//if user is registered
//do something here
}
System.out.println("Check complete");
service.shutdown();//to destroy this service after recieving the data
}
}
}, 100, TimeUnit.MICROSECONDS);

Mouse click event for JFrame change

I want to change a JFrame window to another one with MouseEvent. Code is below.
private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {
String pass;
String user;
user = txtUser.getText();
pass = txtPass.getText();
if(pass.equals("********") && user.equals("**********") )
{
??????????
}
else{
lblDisplay.setText("Please try again.");

If you need to go to another JFrame if the username and password matches, you can do as follows.
private void jButton1MouseClicked(java.awt.event.MouseEvent evt) {
String pass;
String user;
user = txtUser.getText();
pass = txtPass.getText();
if(pass.equals("********") && user.equals("**********"))
{
// Here you can dispose the current window
this.dispose(); // Or you can use this.setVisible(false);
// Then call your next window to appear
new YourNextWindow().setVisible(true);
// And of course you can create an object for that window,
YourNextWindow yourNextWindow = new YourNextWindow();
yourNextWindow.setVisible(true);
} else {
lblDisplay.setText("Please try again.");
}
}
It's better to use this.dispose(); instead of making the JFrame invisible setVisible(false) as it will be still running without any use.
UPDATE
As camickr said it is best to use ActionListener instead of MouseListener.
public void jButton1ActionPerformed(ActionEvent e) {
// Your code here
}

Store and Restore previous userinput texfield

I have two Textfields that can be input by user and will be used for calculation later (Number only), lets say InputX and InputY. And two radio button, Rad1 and Rad2.
When user Choose Rad1, Both TextFiled are Input-able by User and Stored to memory/variable when user input in it. But when user choose Rad2, only InputX is available and InputY is InputY.setText("InputX only"). If User choose the Rad1 back, i want to restore the value that user input to the InputY previously, not showing "InputX Only".
So, My Question is: How to get the previous value from userinput when user choose the Rad1 back, since its has been overridden by Rad2 InputY.setText("InputX Only") ?
Please create a full code example with all possible/alternative code, i'm new in java.
Note: Im using Netbeans v8.0.2 and create form using built in form builder/designer

public class InputValidator extends javax.swing.JFrame {
private static final String INPUT_X_ONLY = "InputX Only";
private String temp = "";
public InputValidator() {
initComponents();
jRadioButton1.setSelected(true);
buttonGroup1.add(jRadioButton1);
buttonGroup1.add(jRadioButton2);
jRadioButton1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
jTextField2.setEditable(true);
jTextField2.setText(temp);
}
});
jRadioButton2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
jTextField2.setEditable(false);
temp = jTextField2.getText();
jTextField2.setText(INPUT_X_ONLY);
}
});
}

How to "ignore/discard" Swing UI events when doing data validations on UI?

There's a text field and when lost focus it will validate the inputs, if not passed, print out the error message (to be simple here just has an empty check). And there's a button next to the text field, it will print out the text once click on it.
As I tried, when input some text and then click the button it will trigger both the focus lost event of text field and the event of button. In a other word, it will do the validation first and then print out the input text.
Here comes my question, what is the good approach to prevent printing out the text if the validation not passed? Or is there a way to "ignore" the click event on button if validation not passed?
I tried to use a boolean flag which indicate the validation result and check the flag when perform the action for button, but I do not think it is a good approach. As I know there's an event dispatcher thread in Swing which deal with the events, is it possible I can cancel the events from here?
Below is a piece of code which explain the question:
public class SimpleDemo
{
public static void main(String[] args)
{
JFrame frame = new JFrame("Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel content = new JPanel(new FlowLayout());
frame.setContentPane(content);
final JTextField textField = new JTextField(10);
textField.addFocusListener(new FocusAdapter()
{
#Override
public void focusLost(FocusEvent e)
{
String text = textField.getText();
// do some validation here, if not validated
// do not trigger the event on button.
if ("".equals(text))
{
System.out.print("please input a text!");
}
}
});
content.add(textField);
JButton button = new JButton("Print Text");
button.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
// action performed for button
String text = textField.getText();
System.out.println(text);
}
});
content.add(button);
frame.setVisible(true);
frame.pack();
}
}

I faces similar issue while working on an application. I solved it like below
I created a abstract class ApplicationFrame which every frame in the application extends
public abstract class ApplicationFrame extends JFrame implements ActionListener {
#Override
final public void actionPerformed(ActionEvent event) {
if(validateInput()){
performAction(event);
}
}
/*
* Sub class should override this method to receive any action
*/
protected void performAction(ActionEvent event) {};
/*
* Sub class should override this method to perform validation
*/
abstract protected boolean validateInput();
}
All Frames will now extend this base frame, as below:
public class Frame1 extends ApplicationFrame{
#Override
protected void performAction(ActionEvent event) {
// perform action
}
#Override
protected boolean validateInput() {
// return true or false depending upon the validation results
}
// if you want to add Action Listener, you need to add like this:
btnSomeButton.addActionListener(this);
}
If you need to handle Focus events, you can make ApplicationFrame or the base frame implement FocusListener.
This is my custom implementation to solve the problem, hope this helps.

Make the button disabled on start-up
Upon lost focus, validate the text & enable button only when the input passes validation.
Upon start of text change, disable the button

It's always makes sense to make ui to communicate with user. So you can show "please input a text" as the default text of the textField when nothing is entered by user.
Here is the code for such custom textField:
public class TextFieldWithDefaultText extends JTextField implements FocusListener{
private final String hint;
public TextFieldWithDefaultText (String $text)
{
super($text);
this.hint = $text;
addFocusListener(this);
}
#Override
public void focusGained (FocusEvent $e)
{
if (this.getText().isEmpty())
{
super.setText("");
}
}
#Override
public void focusLost (FocusEvent $e)
{
if (this.getText().isEmpty())
{
super.setText(hint);
}
}
#Override
public String getText ()
{
String typed = super.getText();
return typed.equals(hint) ? "" : typed;
}
}
Write the acttionListerner for your button like this:
JButton button = new JButton("Print Text");
button.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent e)
{
if(!textField.getText().isEmpty())
System.out.println(textField.getText());
}
});
And ur textField implementation should be :
final TextFieldWithDefaultText textField = new TextFieldWithDefaultText ("please input a text");
Hope this helps :)