Form freezing issues after accessing dialogue box

Question

I'm in the process of creating a login mechanism for a game. If the user inputs an invalid username-password combination, a dialogue box appears telling them their error. But when I click "OK" in the dialogue box, all components in the previous form become inactive.

Here is my code from the event handler method:

//Event Handler
public void actionPerformed(ActionEvent e){

    Scanner fileScan = null;
    Scanner passwordScan = null;


    String lineVar; 
    int lineCount=0;

    //Opens the "Create Account" form
    if (e.getSource()==CreateNew){      
        new CreateAccount();        
    }

    //user tries to login 
    else if(e.getSource()==submit){

        Inputuser = user.getText();
        InputPass = Pass.getText();

        try{
            fileScan = new Scanner(new File(Inputuser + ".txt"));
            filefound = true;
        }

        catch(FileNotFoundException ex){
            JFrame FailureFrame = new JFrame("Something went wrong...");
            JOptionPane.showMessageDialog(FailureFrame, "The username you have entered does not exist in our records. Please try again");
            filefound=false;
        }

        //If the file was found (username exists)
        if (filefound==true){

            //Loops while the username while has more lines of content          
            while(fileScan.hasNext()){
                lineVar = fileScan.next();

                //Each line is considered a token
                passwordScan = new Scanner(lineVar);
                passwordScan.useDelimiter("/n");

                while (passwordScan.hasNext()){
                    lineCount +=1;

                    if (lineCount == 2){

                        if (InputPass.equals( passwordScan.next() ) ){

                                JFrame successframe = new JFrame("Success!");
                                JOptionPane.showMessageDialog(successframe, "Login Successful!");

                                frame.dispose();
                                new MainProfile();

                        }

                        //If the password they entered is wrong     
                        else{
                            JFrame notLogin = new JFrame ("Something went wrong...");           
                            JOptionPane.showMessageDialog(notLogin, "You have entered invalid info. Please try again"); 

                            CompEnable();   

                        }

                    }


                }

            }


        }


    }

}

Also, consider using a modal JDialog instead of two frame, like in [this answer](http://stackoverflow.com/a/20286447/2587435) — Paul Samsotha, Dec 30 '13 at 16:14
Use standard Java variable names if you want people to read your code. Variable names should NOT start with an upper case character. I have NEVER seen a tutorial or example from a text book that does that, so don't make up your own conventions. Follow the standards. — camickr, Dec 30 '13 at 16:25

score 3 · Accepted Answer · edited May 23 '17 at 12:15

There are some hints below to guide you to solve the problem:

Check the while loop, it seems to be blocking the Event Dispatching Thread (a.k.a. EDT) and that's freezing your GUI. Also take a look to Concurrency in Swing trail for further details on how the EDT works and how to deal with it.
You should avoid the use of multiple JFrame and consider use modal JDialog instead: How to Use Modality in Dialogs. Also take a look to this topic: The Use of Multiple JFrames, Good/Bad Practice?
You may want to try Properties to store user passwords and get rid of handling file's IO by using Scanner class. Note: ideally it should be done in a database but in this case you're doing this in a ".txt" file so I think properties would be more appropriate. Take a look to this trail and How to use Java property files? to start with properties.

Off-topic:

Always try to follow Java Code Conventions.

Form freezing issues after accessing dialogue box

1 Answers1