Re: Math.random()

maya <>
Fri, 07 Mar 2008 10:09:29 -0500
maya wrote:

Jeff Higgins wrote:

Daniel Pitts wrote:

maya wrote:

(I want to have option of displaying photos in a random order
instead of in order of img-names (1.jpg, 2.jpg, 3.jpg, etc..))

Try putting the photos into a List object, and then calling
Collections.shuffle() with that list object as the parameter.

A clear winner. :-))

ok, am trying to do this now.. acc to docs it's like a vector except
"synchronized" (not sure what this means..) only thing in Vector you add
elements thus:


but am having problems here:

    ArrayList photos = new ArrayList();

        File directory = new File(System.getProperty("user.dir"));
        String[] textFileNames = directory.list(new FilenameFilter() {
            public boolean accept(File dir, String name) {
        return name.endsWith(".jpg") || name.endsWith( ".JPG");
    for (int i=0; i < textFileNames.length+1; i++) {
            photos.add(i); // error here...

how do I convert this "i" to an object (since this method takes only obj
as argument..)

and then how do I apply Collections.shuffle() to it??

   photos.Collections.shuffle() ?? I dont think so....;)

I really need this today, for some photos I'm putting together for a
friend overseas, sending with a friend who travels today....

thank you very much..

ok, I think got Collections.shuffle() part..

    Collections.shuffle(photos, new Random());

only problem now is how to add all nos. to ArrayList (this has to be 1.4
construction, not 1.5..)

and then how to go from Collections.shuffle to this:

for (int i = 0; i < textFileNames.length; ++i) {
   File oldFile = new File(textFileNames[i]);
   posDot = textFileNames[i].indexOf(".");
   _temp = textFileNames[i].substring(0,posDot);
   File newFile = new File(i+1 + ".jpg");

so imgs are named with nos. at random (i.e., so imgs, after renamed, are
in diff order from orig ones..)

thank you....

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