reading filesnames from a folder

destrosjowl

hi,

i am trying to read file names from a folder to populate a dropdown list in cp5. however, i am receiving a null pointer exception in my loop. i am not sure what the problem is. i appreciate any time, or just an extra pair of eyes, you can lend...

import java.io.File;

File dir = new File("folderName");
File [] files = dir.listFiles();

// here, if i try to print the contents of the files list: println(dir) or println(files), i also receive errors

void setup()
{

}

void draw()
{
  for (int i = 0; i <= files.length - 1; i++)   
  {

    String path = files[i].getAbsolutePath();
    if(path.toLowerCase().endsWith(".properties.ser"))
    {
        println(path.toLowerCase() + ".properties.ser", i);
    }
  }
}

velvetkevorkian

This seems to work for me (from the wiki:

// we'll have a look in the data folder
java.io.File folder = new java.io.File(dataPath(""));

// list the files in the data folder
String[] filenames = folder.list();

// get and display the number of jpg files
println(filenames.length + " jpg files in specified directory");

// display the filenames
for (int i = 0; i < filenames.length; i++) {
  println(filenames[i]);
}

GoToLoop

Processing isn't aware of its own save folder before setup() begins!
You should initialize such classes only after setup() started!

velvetkevorkian

Good spot @GoToLoop. Here's a version that's closer to the original that seems to run OK:

File dir; 
File [] files;

void setup() {
  dir= new File(dataPath(""));
  files= dir.listFiles();
}

void draw() { 
  for (int i = 0; i <= files.length - 1; i++)
  {
    String path = files[i].getAbsolutePath();
    if (path.toLowerCase().endsWith(".properties.ser"))
    {
      println(path.toLowerCase() + ".properties.ser", i);
    }
  }  
}

destrosjowl

thanks all. i'll try these suggestions out.

hi velvet, how do yo not get a null pointer exception at line 10? this code doesn't run for me although it seems it should.

i also receive the same with your first suggestion... a null pointer exception at filenames = folder.list();

import java.io.File;

File folder;
String [] filenames;

void setup()
{
  java.io.File folder = new java.io.File(dataPath(" "));
}

void draw()
{
  filenames = folder.list();
  println(filenames.length + ".properties.ser");

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

cheers!

destrosjowl

deleted the earlier message because i had a bout of idiodacy.

however, using dir = new File(dataPath(" "));, how does one navigate to a level up to where the .pde is stored? i have tried File(../dataPath(" ")) and File(dataPath(../" ")) and other combinations to no avail.

thanks in advance.

velvetkevorkian

Hi, Using sketchPath() should get you there.

java.io.File folder = new java.io.File(sketchPath(""));

Hope that helps.

PhiLho

There should be no space between double quotes in dataPath("")

And if you need the sketch's path, use the sketchPath variable (or the sketchPath() method, with a file name).

destrosjowl

thanks velvet and philo.