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Index › Programming Questions & Help › Programs › Null Point Exception, again...
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Null Point Exception, again... (Read 762 times)
Guilherme
Null Point Exception, again...
Dec 10th, 2009, 12:45pm  
I don't know what to do anymore... Here's the code, line 114 (for(int i = timer.length; i >= 0; i--)...):

Code:

int screenSize, readScore;
int[] timer;
int[] score;

boolean startGame;
boolean pauseGame;
boolean endGame;

SPACE zone;
AVATAR player;

void setup()
{
  screenSize = 400;
  size (screenSize,screenSize);
  frameRate(30);
  
  int[] timer = new int [3];
  int[] score = new int [3];
  
  startGame = false;
  pauseGame = false;
  endGame = false;
  
  zone = new SPACE
  (
  loadImage("figura1.png"), loadImage("figura2.png"), 
  loadImage("figura3.png"), color(27,214,219), (screenSize/2),
  (screenSize/2), (screenSize/15)
  );
  
  player = new AVATAR
  (
  color(31,155,16), (screenSize/2), (screenSize/2),
  (screenSize/15),(screenSize/80)
  );
}

void mousePressed()
{
  startGame =! startGame;
  pauseGame = true;
  
  if(endGame == true)
  {
    endGame = false;
  }
}

void keyPressed()
{
  if (key == 't')
  {
    endGame =! endGame;
  }
}

void draw()
{
  background(color(#141B5D));
  smooth();
  zone.display();
  
  if (endGame == false)
  {
    player.display();
    
    if (startGame == true)
    {
      zone.alphaTest = true;
      player.move();
      
      //TIMER
      timer[0]++;
      if (timer[0] > 9)
      {
        timer[1]++;
        timer[0] = 0;
        
        if(timer [1] > 9)
        {
          timer[2]++;
          timer[1] = 0;
          
          if(timer[2] > 9)
          {
            timer[3]++;
            timer[2] = 0;
            
            if(timer[3] > 9)
            {
              for(int i = 0; i <= timer.length; i++)
              {
                timer [i] = 9;
              }
            }
          }
        }
      }
    }
    
    if(startGame == false && pauseGame == true)
    {
      zone.pause();
    }
  }
  
  if(endGame = true)
  {
    pauseGame = false;    
    player.end();
    zone.end();
    
    for(int i = timer.length; i >= 0; i--)
    {
      score[readScore] = timer[i];
      readScore++;
    }
    
    for(int i = 0; i <= timer.length; i++)
    {
      timer[i] = 0;
    }
  }
}


Thanks in advance.
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Cedric
Re: Null Point Exception, again...
Reply #1 - Dec 10th, 2009, 12:56pm  
hmm timer.length is only 3, right? so there is no timer[3]; only 0,1,2
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PhiLho 
Re: Null Point Exception, again...
Reply #2 - Dec 10th, 2009, 12:58pm  
An NPE, really? I expect more of an ArrayIndexOutOfBounds exception:
Code:
int[] timer = new int [3];
[...]
timer[3]++;

is prone to fail.
So are the check i <= timer.length and the assignment int i = timer.length.
An array initialized at size n goes from 0 to n-1.

[EDIT] Good catch, koogy! I missed the double declaration, too!
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koogy
Re: Null Point Exception, again...
Reply #3 - Dec 10th, 2009, 12:59pm  
you define a global int[] timer

but you are also defining and initialising a new int[] timer within setup() and this is restricted in scope to only setup.

you then use the uninitialised timer in the draw. NPE...

remove the int[] before timer (and score) in setup(), you don't need it.




the next problem you will hit is here:

for(int i = 0; i <= timer.length; i++) {
 timer [i] = 9;
}

use < in the condition.

an array of size 10 has elements numbered from 0 to 9

your loop goes from 0 to 10 because of the equals. 10 > 9... hello Array Index Out Of Bounds Exception!

(curses, too slow again!)

(oh, ok, they both went for the out of bounds exception and didn't spot the local variable. oddly, that was the first thing i saw too)
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Guilherme
Re: Null Point Exception, again...
Reply #4 - Dec 10th, 2009, 1:26pm  
Thanks everyone.
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