JFrame freezes, MouseEvent not responding when clicking 3 out of 4 buttons.

[Tellier]

Hi,

I'm trying to code a simple register which stores names together with their age in a file using the FileWriter & FileReader.
Everything works perfectly until I've added about 2-4 names, then the JFrame stops responding to my actions except when I
click the quitButton. There is no error or anything, the program simply stops responding to any of the actions I've coded it to look for.
Can you see what is causing the problem? I'd love any constructive feedback!

package nameandage;

import java.awt.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;

public class Register extends JFrame {
    
    static Scanner sc = new Scanner(System.in);
    FileWriter fw;
    BufferedWriter bw;
    FileReader fr;
    BufferedReader br;
    
    int cordX, cordY;
    int lineNumber = 0;
    
    static boolean addPressed, listPressed, deletePressed, quitPressed;
    
    // Double buffering
    Image dbImage;
    Graphics dbg;
    
    // Menu Buttons
    Rectangle addButton = new Rectangle(15, 330, 100, 25);
    Rectangle listButton = new Rectangle(125, 330, 100, 25);
    Rectangle deleteButton = new Rectangle(15, 365, 100, 25);
    Rectangle quitButton = new Rectangle(125, 365, 100, 25);
    
    // Variables for screen size
    int
    GWIDTH = 240,
    GHEIGHT = 400;
    
    // Dimension of GWIDTH*GHEIGHT
    Dimension screenSize = new Dimension(GWIDTH, GHEIGHT);
    
    public Register() {
        this.setTitle("Register database");
        this.setSize(screenSize);
        this.setResizable(false);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
        this.setBackground(Color.WHITE);
        this.addMouseListener(new Register.MouseHandler());
        this.addMouseMotionListener(new Register.MouseHandler());
        
    }
    
    public void StartProgram() {
        try{
            fr = new FileReader("Register.txt");
            br = new BufferedReader(fr);
        
            
            while(br.readLine() != null){
            lineNumber++;
            }
            fr.close();
        } catch(IOException ioe){
            //ignore problem
        }
        
    }
    
    @Override
    public void paint(Graphics g){
        dbImage = createImage(getWidth(), getHeight());
        dbg = dbImage.getGraphics();
        draw(dbg);
        g.drawImage(dbImage, 0, 0, this);
    }
    
    public void draw(Graphics g){
        // Menu
        // Button to add person to register
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(addButton.x, addButton.y, addButton.width, addButton.height);
        g.setFont(new Font("Arial", Font.BOLD, 12));
        g.setColor(Color.BLACK);
        g.drawString("Add person", addButton.x+20, addButton.y+17);
        // Button to display the data in the register
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(listButton.x, listButton.y, listButton.width, listButton.height);
        g.setColor(Color.BLACK);
        g.drawString("Display register", listButton.x+6, listButton.y+17);
        // Button to delete the register data
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(deleteButton.x, deleteButton.y, deleteButton.width, deleteButton.height);
        g.setColor(Color.BLACK);
        g.drawString("Delete register", deleteButton.x+9, deleteButton.y+17);
        // Button to exit the program
        g.setColor(Color.LIGHT_GRAY);
        g.fillRect(quitButton.x, quitButton.y, quitButton.width, quitButton.height);
        g.setColor(Color.BLACK);
        g.drawString("Quit program", quitButton.x+12, quitButton.y+17);

        while(addPressed){
            try {
                fw = new FileWriter("Register.txt", true);
                bw = new BufferedWriter(fw);
                String inputName;
                String inputAge;

                inputName = JOptionPane.showInputDialog("Enter the name of the person: ");
                inputAge = JOptionPane.showInputDialog("Enter the age of the person: ");
                
                bw.write(inputName + " " + inputAge + "\r");
                
                bw.close();
                fw = null;
                addPressed = false;
            } catch(IOException e){
                System.out.println("Fail - error");
            }
        } 
        if(listPressed){
            try{
                fr = new FileReader("Register.txt");
                br = new BufferedReader(fr);

                String s;
                int y = 50;
                int x = 20;
                while((s = br.readLine()) != null){
                    if(x == 20 && y < 320){
                        g.setColor(Color.BLACK);
                        g.drawString(s, x, y);
                        y += 20;
                    } else if (y > 320){
                        x = 140;
                        y = 50;
                    } else if(x == 140){
                        g.setColor(Color.BLACK);
                        g.drawString(s, x, y);
                        y += 20;
                    }
                } 
                
            } catch(IOException e){
                System.out.println("Error! ");
            }
        }
        if(deletePressed){
            try {
                fw = new FileWriter("Register.txt");
                bw = new BufferedWriter(fw);
                bw.write("");
                bw.close();
                fw = null;
                deletePressed = false;
            } catch (IOException e){
                //ignore
            }
            JOptionPane.showMessageDialog(null, "The list is now empty");
        }
        repaint();
    }
    
    public class MouseHandler extends MouseAdapter {
        @Override
        public void mouseClicked(MouseEvent e){
            int x = e.getX();
            int y = e.getY();
            
            if( (x > 15 && x < 115) && (y > 330 && y < 355)){
                addPressed = true;
                listPressed = false;
                deletePressed = false;
                quitPressed = false;
            } else if( (x > 125 && x < 225) && (y > 330 && y < 355)){
                addPressed = false;
                listPressed = true;
                deletePressed = false;
                quitPressed = false;
            } else if( (x > 15 && x < 115) && (y > 365 && y < 390)){
                addPressed = false;
                listPressed = false;
                deletePressed = true;
                quitPressed = false;
            } else if( (x > 125 && x < 225) && (y > 365 && y < 390)){
                addPressed = false;
                listPressed = false;
                deletePressed = false;
                quitPressed = true;
                System.exit(0);
            } else {
                addPressed = false;
                listPressed = false;
                deletePressed = false;
                quitPressed = false; 
            }
        }
        @Override
        public void mousePressed(MouseEvent e){
            
        }
    }
    
    private void setLookAndFeel(){
        try {
            UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimusLookAndFeel");
        } catch(Exception exc) {
            // ignore error
        }
    }
    
    public static void main(String[] args) throws Exception{
        
        Register register = new Register();
        
    }
}

[JosAH]

Why aren't you using ordinary JButtons and let them do all that hard work?

kind regards,

Jos

[Norm]

Have you tried debugging the code by adding println statements to print out the values of variables as they are are changed and to show when methods are executed? The print out should help you understand what the code is doing.

[DarrylBurke]

There's a lot wrong with that code. Better go through this tutorial Trail: Creating a GUI With JFC/Swing (The Java™ Tutorials)

db