Question

This is my code for a simple arrow sequencing application.

It generates a random sequence of size 4 which comprise of UP, DOWN, LEFT and/or RIGHT arrow keys and displays them one at a time. If they user repeats the sequence correctly, it displays another sequence of 5 keys. The size of the sequence keeps incrementing as long as the user enters the correct sequence but decrements if an invalid sequence has been entered.

The problem I’m encountering is, the first execution is flawless, it even displays the sequence the second time, but it doesn’t accept my keyboard inputs during the second iteration.

For a better understanding of the problem I have broken it down into the main action performing blocks and the full code as well at the end.

Sequence Generation

for(int flag=1;flag<size;flag++)
    {
    random = randomGenerator.nextInt(4);
    generated[flag]=random;
    setVisible(true);
    switch(random)
        {
            case 0:
            left();
            break;
            case 1:
            up();
            break;
            case 2:
            right();
            break;
            case 3:
            down();
            break;
        }
        delaybig();     
    }

User Input Sequence

public void keyPressed(KeyEvent e)
{
    if(cflag<=size) 
    {
        if(e.getKeyCode()==37)
            {
                entered[cflag]=0;
                cflag++;
                Keys.setText("LEFT");
                left();
            }
        else if(e.getKeyCode()==38)
            {
                entered[cflag]=1;
                cflag++;
                Keys.setText("UP");
                up();
            }
        else if(e.getKeyCode()==39)
            {
                entered[cflag]=2;
                cflag++;
                Keys.setText("RIGHT");
                right();
            }
        else if(e.getKeyCode()==40)
            {
                entered[cflag]=3;
                cflag++;
                Keys.setText("DOWN");
                down();
            }
    else
        {
            Keys.setText("INVALID");
        }
    }

Sequence Comparision using Arrays.equals

if(cflag==size)
    {
        boolean check = Arrays.equals(generated, entered);
        if(check)
            {
                delaysmall();
                Keys.setText("PERFECT");
                size++;
                cflag=1;
                delaysmall();
                Keys.setText("GO AGAIN");
                delaybig();
                restart();  
            }
        else
            {
                delaysmall();
                Keys.setText("FAILED");
                if(size>5)
                    {
                        delaybig();
                        restart();
                        size--;
                        cflag=1;
                    }
            }
    }

Looping Thread

public void restart() 
{ 
    Thread goagain =  new Thread() 
    {
        @Override
        public void run()
             {
                launchframe();
             }
        };
        goagain.start();
}

I’ve spent quite some time on this to no avail so here is the full code just incase you suspect the error likes elsewhere.

import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.util.Random;
import java.util.Arrays;

class ArrowSorrow extends Frame implements KeyListener{

int flag;
Image img;
int random;
int cflag=1,size=5;
boolean ShowImage=true;
int entered[]=new int[50];
int generated[]=new int[50];
TextField Keys=new TextField(8);
Random randomGenerator = new Random();
MediaTracker mt = new MediaTracker(this);

public ArrowSorrow(String title)
    {
        super(title);
    }

public void restart() 
    { 
        // Create a new thread
    Thread goagain =  new Thread() 
    {
        // Override run() to provide the running behavior of this thread.
        @Override
        public void run()
             {
                launchframe();
             }
        };
        goagain.start();
}
public void launchframe()
{
    for(int flag=1;flag<1;flag++)
        generated[flag]=0;
    for(int flag=1;flag<1;flag++)
        entered[flag]=0;
            splash();
    add(Keys);
            delaybig();
    setSize(400,400);
    Keys.setEditable(false);
    Keys.setText("MEMORIZE");
    Keys.addKeyListener(this);      
    setBackground(Color.black);
    setLayout(new FlowLayout());
for(int flag=1;flag<size;flag++)
        {
        random = randomGenerator.nextInt(4);
        generated[flag]=random;
        setVisible(true);
        switch(random)
            {
                case 0:
                left();
                break;
                case 1:
                up();
                break;
                case 2:
                right();
                break;
                case 3:
                down();
                break;
            }
            delaybig();     
        }
        String sequence=new String("");
        for(flag=1;flag<size;flag++)
            {
                sequence=sequence+(Integer.toString(generated[flag]));
            }
            Keys.setText(sequence);
            delaysmall();
            Keys.setText("REPEAT");
            delaysmall();
            setVisible(true);

            addWindowListener(new WindowAdapter()
                {
                    public void windowClosing(WindowEvent we)
                        {
                            dispose();
                        }
                });
    }
public void splash()
    {
    img = ToolKit.getDefaultToolkit().getImage("image address for splashscreen.jpg");
    mt.addImage(img,0);
    repaint();
    setVisible(true);
}

public void left()
{
    img = Toolkit.getDefaultToolkit().getImage("image address for left.jpg");
    mt.addImage(img,0);
    repaint();
    setVisible(true);
}

public void right()
{
    img = Toolkit.getDefaultToolkit().getImage("image address for right.jpg");
    mt.addImage(img,0);
    repaint();
    setVisible(true);
}

public void up()
{
    img = Toolkit.getDefaultToolkit().getImage("image address for up.jpg");
    mt.addImage(img,0);
    repaint();
    setVisible(true);
}

public void down()
{
    img = Toolkit.getDefaultToolkit().getImage("image address down.jpg");
    mt.addImage(img,0);
    repaint();
    setVisible(true);
}
//minor delay
public void delaysmall()
{
    try 
        {
            Thread.sleep(600);
        } 
    catch(InterruptedException ex) 
        {
            Thread.currentThread().interrupt();
        }   
}
//major delay
public void delaybig()
{
    try 
        {
            Thread.sleep(1200);
        } 
    catch(InterruptedException ex) 
        {
            Thread.currentThread().interrupt();
        }   
}

public void paint(Graphics g)
{
super.paint(g); 
if(img != null)
    g.drawImage(img,70,70, this);
else
    g.clearRect(0, 0, getSize().width, getSize().height);
}

public void keyPressed(KeyEvent e)
{
    if(cflag<size)  
    {
        if(e.getKeyCode()==37)
            {
                entered[cflag]=0;
                cflag++;
                Keys.setText("LEFT");
                left();
            }
        else if(e.getKeyCode()==38)
            {
                entered[cflag]=1;
                cflag++;
                Keys.setText("UP");
                up();
            }
        else if(e.getKeyCode()==39)
            {
                entered[cflag]=2;
                cflag++;
                Keys.setText("RIGHT");
                right();
            }
        else if(e.getKeyCode()==40)
            {
                entered[cflag]=3;
                cflag++;
                Keys.setText("DOWN");
                down();
            }
    else
        {
            Keys.setText("INVALID");
        }
    }
//comparing generated sequence and user input sequence      
if(cflag==size)
    {
        boolean check = Arrays.equals(generated, entered);
        if(check)
            {
                delaysmall();
                Keys.setText("PERFECT");
                size++;
                cflag=1;
                delaysmall();
                Keys.setText("GO AGAIN");
                delaybig();
                restart();  
            }
        else
            {
                delaysmall();
                Keys.setText("FAILED");
                if(size>5)
                    {
                        delaybig();
                        restart();
                        size--;
                        cflag=1;
                    }
            }
    }
}
public void keyTyped(KeyEvent e){}
public void keyReleased(KeyEvent e){}
}

class ArrowSorrowLaunch{
public static void main(String args[])
    {
        ArrowSorrow instance=new ArrowSorrow("Arrow Sorrow");
        instance.launchframe();
    }
}

Answer 1

You call launchFrame to start each iteration of the game. However, you are doing a lot of work in launchFrame that should be done only once. You should move that initialization code out of launchFrame and do it only once. In particular you should not repeatedly call Keys.addKeyListener(this); or add multiple window listeners.