Processing 1.0 - Processing Discourse - Counters or KeyListeners

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Index › Programming Questions & Help › Syntax Questions › Counters or KeyListeners

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Counters or KeyListeners (Read 388 times)

thesprucegoose

Counters or KeyListeners
Feb 4^th, 2008, 6:11pm

Hello,

I'm not entirely new to programming, but I am new to Processing. Through my research of the language, I've found that there is no Counter or KeyListeners. Is this the case?

What I'm trying to do is change the background color based on how many time the users presses the UP or DOWN keys (this can be comparable to F1 and F2 keys changing the screen brightness on the Mac).

Anyone have any helpful nuggets of information?

~N. Kaz

extrapixel Full Member Offline Posts: 210 Switzerland	Re: Counters or KeyListeners Reply #1 - Feb 4^th, 2008, 7:22pm the reference is always a good point to start http://processing.org/reference/keyCode.html
	http://www.extrapixel.ch

thesprucegoose

Re: Counters or KeyListeners
Reply #2 - Feb 5^th, 2008, 2:26am

I got that far.

I successfully wrote a program that changed the color of the background to white (when UP is pressed) and to black (when DOWN is pressed) using keyCode. My issue was I couldn't seem to get it to count the different times that I hit UP/DOWN (if keypressed UP == true then x = x + 1) and then apply that to changing a background.

David Wicks

Re: Counters or KeyListeners
Reply #3 - Feb 5^th, 2008, 2:45am

You can store a current value for the background in a variable, then modify that variable whenever a key is pressed.

Code:


int bgColor = 0;

void keyPressed(){
  bgColor += 1;
  background( bgColor );
}

Alternatively, you could store the colors you want in an array, and use the variable as the key for the array.

Code:


int[] colors = new int[10];
int index = 0;

void setup(){
  size(100,100);
  
  for( int i = 0; i < colors.length; i++ ){
    colors[i] = color( random(255), random(255), random(255) );
  }
  
}

void draw(){
  //initiate listeners for key presses
}

void keyPressed(){
  println("key pressed" );
  if( keyCode == UP ){
    index++;
    println("up was pressed");
  } else if ( keyCode == DOWN ){
    index--;
  }
  
  if( index < 0 ) index = colors.length - 1;
  if( index >= colors.length ) index = 0;
  
  background( colors[index] );
}

-David&&sansumbrella

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